ac/Allegro/Allegro_Motor_Drive

Excitation

Output current (A)

Motor supply

Package

Remarks

Page

method

1.2

1.25

1.5

voltage (V)

SLA7022MU

to 46

ZIP15Pin

SMA7022MU

to 46

ZIP15Pin

SLA7029M

to 46

ZIP15Pin

SMA7029M

to 46

ZIP15Pin

SMA7036M

to 46

ZIP15Pin

SDK03M

to 46

SMD16Pin 1 motor driven by 2 packages

SLA7027MU

to 46

ZIP18Pin

UCN5804B

to 35

DIP16Pin

Internal sequencer,

constant voltage driver

SLA7024M

to 46

ZIP18Pin

SLA7032M

to 46

ZIP18Pin

SLA7026M

to 46

ZIP18Pin

SLA7033M

to 46

ZIP18Pin

SLA7042M

to 46

ZIP18Pin

SLA7044M

to 46

ZIP18Pin

2-phase

excitation

2-phase/

1-2 phase

excitation

2W1-2 phase

Micro-step support

■

2-Phase Stepper Motor Unipolar Driver ICs

Supply voltage (V)

Package

page

PG001M

4.5 to 5.5

DIP16Pin

Excitation

Output current (A)

Motor supply

Package

Remarks

Page

method

0.65

0.75

0.8

1.3

1.5

voltage (V)

A3966SA

Vcc to 30

DIP16Pin

A3966SLB

Vcc to 30

SOP16Pin

A3964SLB

Vcc to 30

SOP20Pin

A3953SB

Vcc to 50

DIP16Pin

One motor driven by 2 ICs

A3953SLB

Vcc to 50

SOP16Pin One motor driven by 2 ICs

A2918SW

10 to 45

ZIP18Pin

A3952SB

Vcc to 50

DIP16Pin

One motor driven by 2 ICs

A3952SLB

Vcc to 50

SOP16Pin One motor driven by 2 ICs

A3952SW

Vcc to 50

SIP12Pin

One motor driven by 2 ICs

UDN2916B

10 to 45

DIP24Pin

UDN2916LB

10 to 45

SOP24Pin

UDN2917EB

10 to 45

PLCC44Pin

A3955SB

Vcc to 50

DIP16Pin

One motor driven by 2 ICs

A3955SLB

Vcc to 50

SOP16Pin One motor driven by 2 ICs

A3957SLB

Vcc to 50

SOP24Pin One motor driven by 2 ICs

2-phase/

1-2 phase

excitation

2-phase/1-2
phase/W1-2

phase excitation

2W1-2 phase

excitation/

micro-step

support

4W1-2 phase

excitation/micro-

step support

■

2-Phase Stepper Motor Bipolar Driver ICs

■

3-Phase Stepper Motor Driver Control ICs

Excitation method

Part No.

Motor supply

Package

Remarks

Page

voltage (V)

2-phase/

SI-7600

15 to 45

SOP20Pin

Use with SLA5017 or others

2-3 phase excitation

SI-7600D

DIP20Pin

■

5-Phase Stepper Motor Driver Control ICs

Drive method

Part No.

Motor supply

Package

Remarks

Page

voltage (V)

Pentagon

SI-7502

15 to 42

Powder

Use with SLA6503 and SLA5011

104

connection

coating 27 pin

Selection Guide

Motor Driver ICs

■

Serial Signal Generator IC for SLA704xM

Part No.

Output current Supply voltage

Drive method

Excitation method

Package

Remarks

Page

(A)

(V)

A2918SW

1.5

10 to 45

Bipolar

2-phase/1-2 phase excitation

ZIP18pin

A3952SB

to 50

Bipolar

2-phase/1-2 phase excitation

DIP16pin

One motor driven by 2 ICs

A3952SLB

to 50

Bipolar

2-phase/1-2 phase excitation

SOP16pin

One motor driven by 2 ICs

A3952SW

to 50

Bipolar

2-phase/1-2 phase excitation

SIP12pin

One motor driven by 2 ICs

A3953SB

1.3

to 50

Bipolar

2-phase/1-2 phase excitation

DIP16pin

One motor driven by 2 ICs

A3953SLB

1.3

to 50

Bipolar

2-phase/1-2 phase excitation

SOP16pin

One motor driven by 2 ICs

A3955SB

1.5

to 50

Bipolar

2W/1-2 phase micro-step support

DIP16pin

One motor driven by 2 ICs

A3955SLB

1.5

to 50

Bipolar

2W/1-2 phase micro-step support

SOP16pin

One motor driven by 2 ICs

A3957SLB

1.5

to 50

Bipolar

4W/1-2 phase micro-step support

SOP24pin

One motor driven by 2 ICs

A3964SLB

0.8

to 30

Bipolar

2-phase/1-2 phase excitation

SOP20pin

A3966SA

0.65

to 30

Bipolar

2-phase/1-2 phase excitation

DIP16pin

A3966SLB

0.65

to 30

Bipolar

2-phase/1-2 phase excitation

SOP16pin

PG001M

−

4.5 to 5.5

−

DIP16pin

Serial signal generator IC for

SLA704xM

SDK03M

to 46

Unipolar

2-phase/1-2 phase excitation

SMD16pin

One motor driven by 2 ICs

SI-7502

−

15 to 42

Pentagon connection

5-phase excitation

Powder coat

Control IC

104

27pin

SI-7600

−

15 to 45

Star connection/

2-phase/2-3 phase excitation

SOP20pin

Control IC

delta connection

SI-7600D

−

15 to 45

Star connection/

2-phase/2-3 phase excitation

DIP20pin

Control IC

delta connection

SLA7022MU

to 46

Unipolar

2-phase excitation

ZIP15pin

SLA7024M

1.5

to 46

Unipolar

2-phase/1-2 phase excitation

ZIP18pin

SLA7026M

to 46

Unipolar

2-phase/1-2 phase excitation

ZIP18pin

SLA7027MU

to 46

Unipolar

2-phase/1-2 phase excitation

ZIP18pin

SLA7029M

1.5

to 46

Unipolar

2-phase excitation

ZIP15pin

SLA7032M

1.5

to 46

Unipolar

2-phase/1-2 phase excitation

ZIP18pin

SLA7024M equivalent

SLA7033M

to 46

Unipolar

2-phase/1-2 phase excitation

ZIP18pin

SLA7026M equivalent

SLA7042M

1.2

to 46

Unipolar

2W/1-2 phase micro-step support

ZIP18pin

SLA7044M

to 46

Unipolar

2W/1-2 phase micro-step support

ZIP18pin

SMA7022MU

to 46

Unipolar

2-phase excitation

ZIP15pin

SMA7029M

1.5

to 46

Unipolar

2-phase excitation

ZIP15pin

SMA7036M

1.5

to 46

Unipolar

2-phase excitation

ZIP15pin

SMA7029M equivalent

UCN5804B

1.25

to 35

Unipolar

2-phase/1-2 phase excitation

DIP16pin

Internal sequencer, constant

voltage driver

UDN2916B

0.75

10 to 45

Bipolar

2-phase/1-2 phase/W1-2 phase

DIP24pin

excitation

UDN2916LB

0.75

10 to 45

Bipolar

2-phase/1-2 phase/W1-2 phase

SOP24pin

excitation

UDN2917EB

1.5

10 to 45

Bipolar

2-phase/1-2 phase/W1-2 phase

PLCC44pin

excitation

Product Index by Part Number

Motor Driver ICs

SLA7022MU/SLA7029M/SMA7022MU/SMA7029M

Parameter

Symbol

Ratings

Units

SLA7022MU

SLA7029M

SMA7022MU

SMA7029M

Motor supply voltage

FET Drain-Source voltage

DSS

100

Control supply voltage

TTL input voltage

Reference voltage

REF

Output current

1.5

Power dissipation

4.5 (Without Heatsink)

4.0 (Without Heatsink)

35 (T

=25

28(T

=25

Channel temperature

+150

Storage temperature

stg

−

40 to +150

■

Absolute Maximum Ratings

2-Phase Stepper Motor Unipolar Driver ICs

SLA7022MU/SLA7029M/SMA7022MU/SMA7029M

2-Phase Excitation

=25

Ratings

Parameter

Symbol

SLA7022MU

SLA7029M

SMA7022MU

SMA7029M

Units

min

typ

max

min

typ

max

min

typ

max

min

typ

max

Control supply current

Condition

=44V

Control supply voltage

FET Drain-Source

DSS

100

voltage

Condition

=44V, I

DSS

=250

=44V, I

DSS

=250

=44V, I

DSS

=250

=44V, I

DSS

=250

FET ON voltage

0.85

0.6

0.85

0.6

Condition

=1A, V

=14V

=1A, V

=14V

=1A, V

=14V

=1A, V

=14V

FET drain leakage current

DSS

Condition

DSS

=100V, V

=44V

DSS

=100V, V

=44V

DSS

=100V, V

=44V

DSS

=100V, V

=44V

FET diode forward

1.2

1.1

1.2

1.1

voltage

Condition

=1A

TTL input current

Condition

=2.4V, V

=44V

=2.4V, V

=44V

=2.4V, V

=44V

=2.4V, V

=44V

−

0.8

−

0.8

−

0.8

−

0.8

Condition

=0.4V, V

=44V

=0.4V, V

=44V

=0.4V, V

=44V

=0.4V, V

=44V

TTL input voltage

Condition

=1A

(Active High)

0.8

Condition

DSS

=100V

DSS

=100V

DSS

=100V

DSS

=100V

TTL input voltage

Condition

DSS

=100V

DSS

=100V

DSS

=100V

DSS

=100V

(Active Low)

0.8

Condition

=1A

0.5

Condition

=24V, I

=0.8A

=24V, I

=1A

=24V, I

=0.8A

=24V, I

=1A

Switching time

stg

0.7

Condition

=24V, I

=0.8A

=24V, I

=1A

=24V, I

=0.8A

=24V, I

=1A

0.1

Condition

=24V, I

=0.8A

=24V, I

=1A

=24V, I

=0.8A

=24V, I

=1A

■

Electrical Characteristics

=25

DC characteristics

AC characteristics

SLA7022MU/SLA7029M/SMA7022MU/SMA7029M

2-Phase Stepper Motor Unipolar Driver ICs (2-Phase Excitation)

■

Internal Block Diagram

■

Diagram of Standard External Circuit (Recommended Circuit Constants)

Reg

REF

GND

REF

–

1, 6, 10, 15pin

Description of pins

Excitation input

Active H

OUT A
OUT A
OUT B
OUT B

1pin
6pin

10pin
15pin

Active L

OUT A
OUT A
OUT B
OUT B

REF

3 13

(46V max)

(5V)

Open
collector

Excitation signal time chart

2-phase excitation

clock

1-2 phase excitation

clock 0

2 3

H H H H

H L

H H H H

L H L

●

tdA and tdB are signals before the inverter stage.

: 510

Ω

: 100

Ω

(VR)

: 47k

Ω

: 47k

Ω

: 2.4k

Ω

: 2.4k

Ω

: 330 to 500pF

: 2200pF

: 1.8

Ω

typ(7022MU)

Ω

typ(7029M)

(1 to 2W)

SLA7022MU/SLA7029M/SMA7022MU/SMA7029M

2-Phase Stepper Motor Unipolar Driver ICs (2-Phase Excitation)

■

External Dimensions SLA7022MU/SLA7029M

(Unit: mm)

0.2

24.4

0.2

16.4

0.2

3.2

0.15

0.2

9.9

0.2

Part No.

Lot No.

3.2

0.15

3.8

4.8

0.2

1.7

0.1

2.45

0.2

R-End

6.7

0.5

9.7

+1 –

0.5

(3)

0.55

+0.2

–0.1

0.7

1.15

+0.2

–0.1

P2.03

0.7

=28.42

1.0

0.65

+0.2

–0.1

31.3

0.2

Forming No. No.853

1 2 3 · · · · · · · 15

12 3 · · · · · · · 15

Forming No. No.855

P2.03

0.4

=28.42

0.8

0.65

+0.2

–0.1

0.6

0.55

+0.2 –

0.1

2.2

0.4

6.3

0.6

7.5

0.6

4.6

0.6

1.6

0.6

Epoxy resin package

1.15

+0.2

–0.1

(Unit: mm)

■

External Dimensions SMA7022MU/SMA7029MA

Forming No. No.1054

0.2

Part No.

Lot No.

0.2

2.5

0.2

1.45

0.15

6.7

0.5

(9.7)

(3)

0.55

+0.2

–0.1

0.7

P2.03

0.1

14=28.42

0.65

+0.2

–0.1

1 2 3 · · · · · · · 15

12 3 · · · · · · · 15

P2.03

0.1

14=28.42

1.16

0.15

0.6

0.55

+0.2 –

0.1

1.2

0.1

(5.9)

(4.6)

1.6

0.6

1.16

+0.2

–0.1

0.62

0.1

(7.5)

Epoxy resin package

8.5ma

10.2

0.2

31.3

+0.2

Forming No. No.1055

SLA7022MU/SLA7029M/SMA7022MU/SMA7029M

2-Phase Stepper Motor Unipolar Driver ICs (2-Phase Excitation)

■

Determining the Output Current

Fig. 1 shows the waveform of the output current (motor coil cur-

rent). The method of determining the peak value of the output

current (I

) based on this waveform is shown below.

(Parameters for determining the output current I

)

: Reference supply voltage

: Voltage-divider resistors for the reference supply voltage

: Current sense resistor

(1) Normal rotation mode

is determined as follows when current flows at the maximum

level during motor rotation. (See Fig.2.)

(2) Power down mode

The circuit in Fig.3 (rx and Tr) is added in order to decrease the

coil current. I

is then determined as follows.

Equation (2) can be modified to obtain equation to determine rx.

Fig. 4 and 5 show the graphs of equations (1) and (2) respec-

tively.

(NOTE)

Ringing noise is produced in the current sense resistor R

when

the MOSFET is switched ON and OFF by chopping. This noise

is also generated in feedback signals from R

which may there-

fore cause the comparator to malfunction. To prevent chopping

malfunctions, r

) and C

) are added to act as a noise filter.

)

7,(9)

3,(13)

Fig. 2 Normal mode

Phase A

Fig. 1 Waveform of coil current (Phase A excitation ON)

)

7,(9)

3,(13)

Power down
signal

Fig. 3 Power down mode

Current sense resistor R

(

Ω

)

Output current I

(A)

=510

Ω

=100

Ω

∞

=5V

Fig. 4 Output current I

vs. Current sense resistor R

Fig. 5 Output current I

OPD

vs. Variable current sense resistor rx

2.0

1.5

1.0

0.5

200

400

600

800

Variable current sense resistor r

(

Ω

)

Output current I

OPD

(A)

1000

1200

=0.5

Ω

=0.8

Ω

OPD

1+ R

=510

Ω

=100

Ω

=5V

)

2 ·

Application Notes

However, when the values of these constants are increased,

the response from R

to the comparator becomes slow. Hence

the value of the output current I

is somewhat higher than the

calculated value.

•

OPD

−

................................................................ (1)

≅

•

......................................................... (2)

OPD

≅

•

)

•

SLA7022MU/SLA7029M/SMA7022MU/SMA7029M

2-Phase Stepper Motor Unipolar Driver ICs (2-Phase Excitation)

■

Determining the chopper frequency

Determining T

OFF

The SLA7000M and SMA7000M series are self-excited chop-

pers. The chopping OFF time T

OFF

is fixed by r

and r

connected to terminal Td.

OFF

can be calculated using the following formula:

The circuit constants and the T

OFF

value shown below are rec-

ommended.

OFF

= 12

s at r

=47k

Ω

, C

=500pF, V

=5V

10 12

30
35
40

Motor coil resistance R

(

Ω

)

ON time T

( s)

=36V

Chopping frequency f (kHz)

OFF

=12 s

Ω

=1~3ms

= =

47k

Ω

500pF

Fig. 6 Chopper frequency vs. Motor coil resistance

■

Chopper frequency vs. Supply voltage

f (kHz)

(V)

Motor : 23LM-C202

= 0.8A at V

=24V

Ω

■

Chopper frequency vs. Output current

f (kHz)

(A)

0.2

0.4

0.6

0.8

1.0

Motor : 23LM-C202

=24V

Ω

OFF

≅−

•

1 n

−

•

−

)

SLA7022MU/SLA7029M/SMA7022MU/SMA7029M

2-Phase Stepper Motor Unipolar Driver ICs (2-Phase Excitation)

200

500

Case temperature rise

∆

–

(

Motor : PH265-01B
Motor current I

=0.8A

=25

=24V, V

=24V

2-phase excitation

Response frequency (pps)

Without heatsink
Natural cooling

( 4 pin)

200

500

Case temperature rise

∆

–

(

Motor : PH265-01B
Motor current I

=0.8A

=25

=24V, V

=24V

2-phase excitation

Response frequency (pps)

Without heatsink
Natural cooling

( 4 pin)

200

500

Case temperature rise

∆

–

(

Motor : PH265-01B
Motor current I

=0.8A

=25

=24V, V

=24V

2-phase excitation

Response frequency (pps)

Without heatsink
Natural cooling

( 4 pin)

200

500

Case temperature rise

∆

–

(

Motor : PH265-01B
Motor current I

=0.8A

=25

=24V, V

=24V

2-phase excitation

Response frequency (pps)

Without heatsink
Natural cooling

( 4 pin)

Thermal characteristics

SLA7022MU

SLA7029M

SMA7022MU

SMA7029MU

■

Thermal Design

An outline of the method for calculating heat dissipation is shown below.

(1)Obtain the value of P

that corresponds to the motor coil

current I

from Fig. 7 "Heat dissipation per phase P

vs. Out-

put current I

Output current I

(A)

Heat dissipation per phase P

(W)

Motor : 23LM-C004
Holding mode

0.2

0.4

0.6

0.8

1.0

1.2

1.0

0.8

0.6

0.4

0.2

=44V

36V

24V

15V

∆

j–

∆

–

∆

Natural cooling
Without heatsink

150

100

Total Power (W)

(

Fig. 7 Heat dissipation per phase P

vs. Output current I

Fig. 8 Temperature rise

(2) The power dissipation P

diss

is obtained using the following formula.

2-phase excitation: P

diss

≅

+0.015

(W)

1-2 phase excitation: P

diss

≅

+0.015

(W)

(3) Obtain the temperature rise that corresponds to the calcu-

lated value of P

diss

from Fig. 8 "Temperature rise."

1.2

0.8

0.6

0.4

0.2

0.4

0.6

0.8

1.0

Heat dissipation per phase P

(W)

Output current I

(A)

36V

24V

15V

=44V

Motor : 23LM-C202
Holding mode

∆

j–

∆

–

∆

Natural cooling
Without heatsink

150

100

Total Power (W)

(

SLA7022MU, ASMA7022MU

SLA7000M series

SLA7029M, SMA7029M

SMA7000M series

3
2

SMA7036M

2-Phase Stepper Motor Unipolar Driver IC

SMA7036M

Parameter

Symbol

Ratings

Units

Motor supply voltage

Control supply voltage

FET Drain-Source voltage

DSS

100

TTL input voltage

−

0.3 to +7

SYNC terminal voltage

SYNC

−

0.3 to +7

Reference voltage

REF

−

0.3 to +7

Sense voltage

−

5 to +7

Output current

1.5

Power dissipation

4.0 (T

=25

28 (T

=25

Channel temperature

150

Storage temperature

stg

−

40 to +150

Ambient operating temperature

−

20 to +85

■

Absolute Maximum Ratings

■

Electrical Characteristics

Parameter

Symbol

Ratings

Units

min

typ

max

Control supply current

Condition

=44V

Control supply voltage

FET Drain-Source

DSS

100

voltage

Condition

=44V, I

DSS

=250

FET ON voltage

0.6

Condition

=1A, V

=10V

FET diode forward voltage

1.1

Condition

=1A

FET drain leakage current

DSS

250

Condition

DSS

=100V, V

=44V

Condition

=1A

0.8

Condition

DSS

=100V

IN terminal

Condition

DSS

=100V

0.8

Condition

=1A

Condition

=44V, V

=0 or 5V

SYNC

4.0

Condition

Synchronous chopping mode

SYNC

0.8

SYNC terminal

Condition

Asynchronous chopping mode

SYNC

0.1

Condition

=44V, V

=5V

SYNC

−

0.1

Condition

=44V, V

=0V

REF

2.0

Condition

Reference voltage input

REF

4.0

5.5

REF terminal

Condition

Output FET OFF

REF

Condition

No synchronous trigger

REF

Ω

Condition

Resistance between GND and REF terminal at synchronous trigger

1.5

Condition

=24V, I

=1A

0.5

Switching time

Condition

=24V, I

=1A

stg

0.9

Condition

=24V, I

=1A

0.1

Condition

=24V, I

=1A

Chopping OFF time

OFF

Condition

=24V

Active H

Active L

Input
current

Input
voltage

Input
current

Input
voltage

Input
current

Internal
resistance

2-Phase Excitation

DC characteristics

AC characteristics

SMA7036M

2-Phase Stepper Motor Unipolar Driver IC (2-Phase Excitation)

■

Internal Block Diagram

■

Diagram of Standard External Circuit (Recommended Circuit Constants)

Excitation signal time chart

2-phase excitation

clock

: 8k

Ω

: 2k

Ω

(VR)

(1 to 2W) : 1

Ω

typ

PchMOS

: HN1J02FU (Toshiba)

Inv

: 7404

1, 6, 10, 15pin

Description of pins

Chopping

blanking timer

(5 s typ)

Chopping

blanking timer

(5 s typ)

Chopping

OFF timer

(12 s typ)

Chopping

OFF timer

(12 s typ)

Synchronous

chopping

circuit

Synchronous

chopping

circuit

MOSFET

gate drive

circuit

MOSFET

gate drive

circuit

IN A

IN B

Rs A

SYNC A

SYNC B

GND A

REF A

REF B

GND B

Oscillator

Reg.

Rs B

+
−

Excitation input

Active H

OUT A
OUT A
OUT B
OUT B

1pin
6pin

10pin
15pin

Active L

OUT A
OUT A
OUT B
OUT B

Disable (High Active)

Vb (5V)

Vcc (46V max)

PchMOS

Inv

SMA7036M

Sync

Ref

Sync

SMA7036M

2-Phase Stepper Motor Unipolar Driver IC (2-Phase Excitation)

■

Outline

SMA7036M is a stepper motor driver IC developed to reduce

the number of external parts required by the conventional

SMA7029M. This IC successfully eliminates the need for some

external parts without sacrificing the features of SMA7029M.

The basic function pins are compatible with those of SMA7029M.

■

Notes on Replacing SMA7029M

SMA7036M is pin-compatible with SMA7029M. When using

the IC on an existing board, the following preparations are nec-

essary:

(1) Remove the resistors and capacitors attached for setting

the chopping OFF time. (r

, r

, C

, and C

in the catalog)

(2) Remove the resistors and capacitors attached for preventing

noise in the detection voltage V

from causing malfunction-

ing and short the sections from which the resistors were re-

moved using jumper wires. (r

, r

, C

, and C

in the catalog)

(3) Normally, keep pins 2 and 11 grounded because their func-

tions have changed to synchronous and asynchronous

switching (SYNC terminals). For details, see "Circuit for Pre-

venting Abnormal Noise When the Motor Is Not Running (Syn-

chronous circuit)." (Low: asynchronous, High: synchronous)

■

Circuit for Preventing Abnormal Noise When the

Motor Is Not Running (Synchronous Circuit)

A motor may generate abnormal noise when it is not running.

This phenomenon is attributable to asynchronous chopping be-

tween phases A and B. To prevent the phenomenon, SMA7036M

contains a synchronous chopping circuit. Do not leave the SYNC

terminals open because they are for CMOS input.

■

Synchronous circuit operating waveform

SYNC_A

SYNC voltage : Low
SYNC voltage : High

→

Chopping asynchronous

→

Chopping synchronous

TTL, etc.

SYNC_B

SMA7036M

ONE SHOT

(tw=2 S)

Sync/async
switching signal

To comparator
(high impedance)

REF_A

REF_B

REF

waveform

REF

SMA7036M

FET A/A
gate drive signal

Ω

(typ.)

Ω

(typ.)

FET B/B
gate drive signal

ONE SHOT

(tw=2 S)

REF

Phase A

REF

Synchronous circuit ON

Synchronous circuit OFF

Phase B

Application Notes

Connect TTL or similar to the SYNC terminals and switch the

SYNC terminal level high or low.

When the motor is not running, set the TTL signal high (SYNC

terminal voltage: 4 V or more) to make chopping synchronous.

When the motor is running, set the TTL signal low (SYNC terminal

voltage: 0.8 V or less) to make chopping asynchronous. If chop-

ping is set to synchronous when the motor is running, the motor

torque deteriorates before the coil current reaches the set value.

If no abnormal noise occurs when the motor is not running,

ground the SYNC terminals (TTL not necessary).

The built-in synchronous chopping circuit superimposes a trigger

signal on the REF terminal for synchronization between the two

phases. The figure below shows the internal circuit of the REF

terminal. Since the

∆

REF

varies depending on the values of R1

and R2, determine these values for when the motor is not run-

ning within the range where the two phases are synchronized.

SMA7036M

2-Phase Stepper Motor Unipolar Driver IC (2-Phase Excitation)

Phase A

)

7,(9)

3,(13)

)

7,(9)

3,(13)

Power down
signal

■

Determining the Output Current

Fig. 1 shows the waveform of the output current (motor coil cur-

rent). The method of determining the peak value of the output

current (I

) based on this waveform is shown below.

(Parameters for determining the output current I

)

: Reference supply voltage

: Voltage-divider resistors for the reference supply voltage

: Current sense resistor

(1) Normal rotation mode

is determined as follows when current flows at the maximum

level during motor rotation. (See Fig.2.)

(2) Power down mode

The circuit in Fig.3 (r

and T

) is added in order to decrease the

coil current. I

is then determined as follows.

Equation (2) can be modified to obtain equation to determine rx.

Fig. 4 and 5 show the graphs of equations (1) and (2) respec-

tively.

Fig. 2 Normal mode

Fig. 1 Waveform of coil current (Phase A excitation ON)

Fig. 3 Power down mode

Current sense resistor R

(

Ω

)

Output current I

(A)

=510

Ω

=100

Ω

∞

=5V

Fig. 4 Output current I

vs. Current sense resistor R

Fig. 5 Output current I

OPD

vs. Variable current sense resistor rx

2.0

1.5

1.0

0.5

200

400

600

800

Variable current sense resistor r

(

Ω

)

Output current I

OPD

(A)

1000

1200

=0.5

Ω

=0.8

Ω

OPD

1+ R

=510

Ω

=100

Ω

=5V

)

2 ·

•

OPD

−

................................................................ (1)

≅

•

......................................................... (2)

OPD

≅

•

)

•

SLA7027MU/SLA7024M/SLA7026M

Parameter

Symbol

Ratings

Units

SLA7027MU

SLA7024M

SLA7026M

Motor supply voltage

FET Drain-Source voltage

DSS

100

Control supply voltage

TTL input voltage

Reference voltage

REF

Output current

1.5

Power dissipation

4.5 (Without Heatsink)

35 (T

=25

Channel temperature

+150

Storage temperature

stg

−

40 to +150

■

Electrical Characteristics

■

Absolute Maximum Ratings

2-Phase Stepper Motor Unipolar Driver ICs

SLA7027MU/SLA7024M/SLA7026M

2-Phase/1-2 Phase Excitation

(Ta=25

Ratings

Parameter

Symbol

SLA7027MU

SLA7024M

SLA7026M

Units

min

typ

max

min

typ

max

min

typ

max

Control supply current

Condition

=44V

Control supply voltage

FET Drain-Source voltage

DSS

100

Condition

=44V, I

DSS

=250

=44V, I

DSS

=250

=44V, I

DSS

=250

FET ON voltage

0.85

0.6

0.85

Condition

=1A, AV

=14V

=1A, V

=14V

=3A, V

=14V

FET drain leakage current

DSS

Condition

DSS

=100V, V

=44V

DSS

=100V, V

=44V

DSS

=100V, V

=44V

FET diode forward voltage

1.2

1.1

2.3

Condition

=1A

=3A

TTL input current

Condition

=2.4V, V

=44V

=2.4V, V

=44V

=2.4V, V

=44V

−

0.8

−

0.8

−

0.8

Condition

=0.4V, V

=44V

=0.4V, V

=44V

=0.4V, V

=44V

TTL input voltage

Condition

=1A

=3A

(Active High)

0.8

Condition

DSS

=100V

DSS

=100V

DSS

=100V

TTL input voltage

Condition

DSS

=100V

DSS

=100V

DSS

=100V

(Active Low)

0.8

Condition

=1A

=3A

0.5

Condition

=24V, I

=0.8A

=24V, I

=1A

=24V, I

=1A

Switching time

stg

0.7

Condition

=24V, I

=0.8A

=24V, I

=1A

=24V, I

=1A

0.1

Condition

=24V, I

=0.8A

=24V, I

=1A

=24V, I

=1A

DC characteristics

AC characteristics

SLA7027MU/SLA7024M/SLA7026M

2-Phase Stepper Motor Unipolar Driver ICs (2-Phase/1-2 Phase Excitation)

■

Internal Block Diagram

■

Diagram of Standard External Circuit(Recommended Circuit Constants)

1, 8, 11, 18pin

Description of pins

Excitation input

Active H

Active L

Pin 1

OUT

Pin 8

OUT

Pin 11

OUT

Pin 18

OUT

Reg

IN A

REF

Reg

IN A

IN B

REF

+
–

Active High

7 12

OUT

REF

3 14

Active
High

(46V max)

(5V)

SLA7024M

7026M

7027MU

Active Low

7 12

OUT

REF

3 14

Active
Low

(46V max)

(5V)

SLA7024M

7026M
7027MU

: 510

Ω

: 100

Ω

(VR)

: 47k

Ω

: 47k

Ω

: 2.4k

Ω

: 2.4k

Ω

: 470pF

: 2200pF

: 1

Ω

typ(7024M)

0.68

Ω

typ(7026M)

1.8

Ω

typ(7027MU)

1-2 phase excitation

clock

H H H H H

H H

H H H

H H H H H L

H H H H H

H H H H H L

H H H H

: 510

Ω

: 100

Ω

(VR)

: 47k

Ω

: 47k

Ω

: 2.4k

Ω

: 2.4k

Ω

: 470pF

: 2200pF

: 1

Ω

typ(7024M)

0.68

Ω

typ(7026M)

1.8

Ω

typ(7027MU)

(1 to 2W)

1-2 phase excitation

clock

H H L

H H H

Excitation signal time chart

2-phase excitation

clock

Excitation signal time chart

2-phase excitation

clock

(1 to 2W)

SLA7027MU/SLA7024M/SLA7026M

2-Phase Stepper Motor Unipolar Driver ICs (2-Phase/1-2 Phase Excitation)

)

9,(10)

3,(14)

)

9,(10)

3,(14)

Power down
signal

■

Determining the Output Current

Fig. 1 shows the waveform of the output current (motor coil cur-

rent). The method of determining the peak value of the output

current (I

) based on this waveform is shown below.

(Parameters for determining the output current I

)

: Reference supply voltage

: Voltage-divider resistors for the reference supply voltage

: Current sense resistor

(1) Normal rotation mode

is determined as follows when current flows at the maximum

level during motor rotation. (See Fig.2.)

(2) Power down mode

The circuit in Fig.3 (rx and Tr) is added in order to decrease the

coil current. I

is then determined as follows.

Equation (2) can be modified to obtain equation to determine rx.

Fig. 4 and 5 show the graphs of equations (1) and (2) respec-

tively.

(NOTE)

Ringing noise is produced in the current sense resistor R

when

the MOSFET is switched ON and OFF by chopping. This noise

is also generated in feedback signals from R

which may there-

fore cause the comparator to malfunction. To prevent chopping

malfunctions, r

) and C

) are added to act as a noise filter.

Fig. 2 Normal mode

Phase A

Fig. 1 Waveform of coil current (Phase A excitation ON)

Fig. 3 Power down mode

Current sense resistor R

(

Ω

)

Output current I

(A)

=510

Ω

=100

Ω

∞

=5V

Fig. 4 Output current I

vs. Current sense resistor R

Fig. 5 Output current I

OPD

vs. Variable current sense resistor rx

2.0

1.5

1.0

0.5

200

400

600

800

Variable current sense resistor r

(

Ω

)

Output current I

OPD

(A)

1000

1200

=0.5

Ω

=0.8

Ω

OPD

1+ R

=510

Ω

=100

Ω

=5V

)

2 ·

Application Notes

•

OPD

−

However, when the values of these constants are increased,

the response from R

to the comparator becomes slow. Hence

the value of the output current I

is somewhat higher than the

calculated value.

................................................................ (1)

≅

•

......................................................... (2)

OPD

≅

•

)

•

SLA7027MU/SLA7024M/SLA7026M

2-Phase Stepper Motor Unipolar Driver ICs (2-Phase/1-2 Phase Excitation)

SLA7027MU/SLA7024M/SLA7026M

Fig. 6 Chopper frequency vs. Motor coil resistance

10 12

30
35
40

Motor coil resistance R

(

Ω

)

ON time T

( s)

=24V

=36V

Chopping frequency f (kHz)

OFF

=12 s

Ω

=1~3ms

= =

47k

Ω

500pF

■

Determining the chopper frequency

Determining T

OFF

The SLA7000M series are self-excited choppers. The chopping

OFF time T

OFF

is fixed by r

and r

connected to terminal

Td.

OFF

can be calculated using the following formula:

The circuit constants and the T

OFF

value shown below are rec-

ommended.

OFF

= 12

s at r

=47k

Ω

, C

=500pF, V

=5V

■

Chopper frequency vs. Supply voltage

f (kHz)

(V)

Motor : 23LM-C202

= 0.8A at V

=24V

Ω

■

Chopper frequency vs. Output current

f (kHz)

(A)

0.2

0.4

0.6

0.8

1.0

Motor : 23LM-C202

=24V

Ω

OFF

≅−

•

1 n

−

•

−

)

SLA7027MU/SLA7024M/SLA7026M

2-Phase Stepper Motor Unipolar Driver ICs (2-Phase/1-2 Phase Excitation)

Thermal characteristics

Fig. 7 Heat dissipation per phase P

vs. Output current I

SLA7027MU

SLA7024M

1.2

0.8

0.6

0.4

0.2

0.4

0.6

0.8

1.0

Heat dissipation per phase P

(W)

Output current I

(A)

36V

24V

15V

=44V

Motor : 23LM-C202
Holding mode

Output current I

(A)

Heat dissipation per phase P

(W)

Motor : 23LM-C004
Holding mode

0.2

0.4

0.6

0.8

1.0

1.2

1.0

0.8

0.6

0.4

0.2

=44V

36V

24V

15V

Heat dissipation per phase P

(W)

Motor : 23PM-C503
Holding mode

36V

15V

24V

=44V

4.0

3.0

2.0

1.0

2.0

3.0

Output current I

(A)

SLA7026M

SLA7027MU

200

500

Case temperature rise

∆

–

(

Motor : PH265-01B
Motor current I

=0.8A

=25

=24V, V

=24V

2-phase excitation

Response frequency (pps)

Without heatsink
Natural cooling

( 4 pin)

200

500

Case temperature rise

∆

–

(

Motor : PH265-01B
Motor current I

=0.8A

=25

=24V, V

=24V

2-phase excitation

Response frequency (pps)

Without heatsink
Natural cooling

( 4 pin)

100

500

Case temper

ature r

ise

∆

–

(

Response frequency (pps)

Without heatsink
Natural cooling

Motor : 23PM-C705
Motor current I

=1.5A

=25

=24V, V

=24V

2-phase excitation

( 4 pin)

SLA7024M

SLA7026M

Fig. 8 Temperature rise

∆

j–

∆

–

∆

Natural cooling
Without heatsink

150

100

Total Power (W)

(

■

Thermal Design

An outline of the method for calculating heat dissipation is shown be-

low.

(1) Obtain the value of P

that corresponds to the motor coil current

from Fig. 7 "Heat dissipation per phase P

vs. Output current I

(2) The power dissipation Pdiss is obtained using the following formula.

2-phase excitation: P

diss

≅

+0.015

(W)

1-2 phase excitation: P

diss

≅

+0.015

(W)

(3) Obtain the temperature rise that corresponds to the calcu-

lated value of Pdiss from Fig. 8 "Temperature rise."

3
2

SLA7032M/SLA7033M

Ratings

Parameter

Symbol

SLA7032M

SLA7033M

Units

min

typ

max

min

typ

max

Control supply current

Condition

=44V

Control supply voltage

FET Drain-Source

DSS

100

voltage

Condition

=44V, I

DSS

=250

=44V, I

DSS

=250

FET ON voltage

0.6

0.85

Condition

=1A, V

=14V

=3A, V

=14V

FET diode forward voltage

1.1

2.3

Condition

=1A

=3A

FET drain leakage current

DSS

250

Condition

DSS

=100V, V

=44V

DSS

=100V, V

=44V

2.0

Condition

=1A

=3A

0.8

Condition

DSS

=100V

DSS

=100V

IN terminal

2.0

Condition

DSS

=100V

DSS

=100V

0.8

Condition

=1A

=3A

Condition

=44V, V

=0 or 5V

=44V, V

=0 or 5V

SYNC

4.0

Condition

Synchronous chopping mode

SYNC

0.8

SYNC terminal

Condition

Asynchronous chopping mode

SYNC

0.1

Condition

=44V, V

=5V

=44V, V

=5V

SYNC

−

0.1

−

0.1

Condition

=44V, V

=0V

=44V, V

=0V

REF

2.0

Condition

Reference voltage input

REF

4.0

5.5

4.0

5.5

REF terminal

Condition

Output FET OFF

REF

Condition

No synchronous trigger

REF

Ω

Condition Resistance between GND and REF terminal at synchronous trigger

Resistance between GND and REF terminal at synchronous trigger

0.5

Condition

=24V, I

=1A

=24V, I

=1A

Switching time

stg

0.7

Condition

=24V, I

=1A

=24V, I

=1A

0.1

Condition

=24V, I

=1A

=24V, I

=1A

Chopping OFF time

OFF

Condition

=24V

2-Phase Stepper Motor Unipolar Driver ICs

SLA7032M/SLA7033M

2-Phase/1-2 Phase Excitation

(Ta=25

Parameter

Symbol

Ratings

Units

SLA7032M

SLA7033M

Motor supply voltage

Control supply voltage

FET Drain-Source voltage

DSS

100

TTL input voltage

−

0.3 to +7

SYNC terminal voltage

SYNC

−

0.3 to +7

Reference voltage

REF

−

0.3 to +7

Sense voltage

−

5 to +7

Output current

1.5

Power dissipation

4.5 (Without Heatsink)

35 (T

= 25

Channel temperature

+150

Storage temperature

stg

−

40 to +150

DC characteristics

■

Absolute Maximum Ratings

■

Electrical Characteristics

OUT

Input
current

Input
voltage

Input
current¨

Input
current

Internal

resistance

AC characteristics

SLA7032M/SLA7033M

2-Phase Stepper Motor Unipolar Driver IC (2-Phase/1-2 Phase Excitation)

Active
Low

Vb (5V)

Vcc (46Vmax)

RsA

RsB

A R

OUT

SLA7032M
SLA7033M

VsA

VsB

OUT

SYNC A

SYNC B

Active Low

■

Internal Block Diagram

■

Diagram of Standard External Circuit (Recommended Circuit Constants)

Active High

+
−

1, 8, 11, 18pin

Description of pins

Chopping

blanking timer

(5 s typ)

Synchronous

chopping

circuit

Synchronous

chopping

circuit

MOSFET

gate drive

circuit

MOSFET

gate drive

circuit

IN A

IN B

Vs A

Vs B

Rs A

SYNC A

SYNC B

G A

G B

Oscillator

Reg.

Rs B

+
−

Excitation input

Active H

OUT A
OUT A
OUT B
OUT B

1pin
8pin

11pin
18pin

Active L

OUT A
OUT A
OUT B
OUT B

Chopping

OFF timer

(12 s typ)

Chopping

blanking timer

(5 s typ)

Chopping

OFF timer

(12 s typ)

Active
High

Vb (5V)

Vcc (46Vmax)

RsA

RsB

A R

OUT

SLA7032M
SLA7033M

VsA

VsB

OUT

SYNC A

SYNC B

(1 to 2W)

: 4k

Ω

: 1k

Ω

(VR)

: 1

Ω

typ(7032M)

0.68

Ω

typ(7033M)

: 4k

Ω

: 1k

Ω

(VR)

: 1

Ω

typ(7032M)

0.68

Ω

typ(7033M)

1-2 phase excitation

clock

H H L

H H H

H H H L

Excitation signal time chart

2-phase excitation

clock

Excitation signal time chart

2-phase excitation

clock

1-2 phase excitation

clock

H H H H H L

H H

H H H

H H H H H

H H H H

(1 to 2W)

SLA7032M/SLA7033M

2-Phase Stepper Motor Unipolar Driver IC (2-Phase/1-2 Phase Excitation)

■

Outline

SLA7032M (SLA7033M) is a stepper motor driver IC developed

to reduce the number of external parts required by the conven-

tional SLA7024M (SLA7026M). This IC successfully eliminates

the need for some external parts without sacrificing the features

of SLA7024M (SLA7026M). The basic function pins are com-

patible with those of SLA7024M (SLA7026M).

■

Notes on Replacing SLA7024M (SLA7026M)

SLA7032M (SLA7033M) is pin-compatible with SLA7024M

(SLA7026M). When using the IC on an existing board, the fol-

lowing preparations are necessary:

(1) Remove the resistors and capacitors attached for setting

the chopping OFF time. (r

, r

, C

, and C

in the catalog)

(2) Remove the resistors and capacitors attached for preventing

noise in the detection voltage V

from causing malfunction-

ing and short the sections from which the resistors were re-

moved using jumper wires. (r

, r

, C

, and C

in the catalog)

(3) Normally, keep pins 2 and 13 grounded because their func-

tions have changed to synchronous and asynchronous

switching (SYNC terminals). For details, see "Circuit for Pre-

venting Abnormal Noise When the Motor Is Not Running (Syn-

chronous circuit)." (Low: asynchronous, High: synchronous)

■

Circuit for Preventing Abnormal Noise When the

Motor Is Not Running (Synchronous Circuit)

A motor may generate abnormal noise when it is not running. This

phenomenon is attributable to asynchronous chopping between

phases A and B. To prevent the phenomenon, SLA7032M

(SLA7033M) contains a synchronous chopping circuit. Do not leave

Synchronous circuit operating waveform

SYNC_A

SYNC voltage : Low
SYNC voltage : High

→

Chopping asynchronous

→

Chopping synchronous

TTL, etc.

SYNC_B

SLA7032M
SLA7033M

Sync/async switching
signal

To comparator
(high impedance)

REF_A

REF_B

REF

waveform

REF

SLA7032M
SLA7033M

FET A/A
gate drive signal

Ω

(typ.)

Ω

(typ.)

FET B/B
gate drive signal

ONE SHOT

(tw=2 S)

ONE SHOT

(tw=2 S)

REF

Phase A

REF

Synchronous circuit ON

Synchronous circuit OFF

Phase B

Application Notes

the SYNC terminals open because they are for CMOS input.

Connect TTL or similar to the SYNC terminals and switch the

SYNC terminal level high or low.

When the motor is not running, set the TTL signal high (SYNC

terminal voltage: 4 V or more) to make chopping synchronous.

When the motor is running, set the TTL signal low (SYNC terminal

voltage: 0.8 V or less) to make chopping asynchronous. If chop-

ping is set to synchronous at when the motor is running, the motor

torque deteriorates before the coil current reaches the set value.

If no abnormal noise occurs when the motor is not running,

ground the SYNC terminals (TTL not necessary).

The built-in synchronous chopping circuit superimposes a trigger

signal on the REF terminal for synchronization between the two

phases. The figure below shows the internal circuit of the REF

terminal. Since the

∆

REF

varies depending on the values of R1

and R2, determine these values for when the motor is not run-

ning within the range where the two phases are synchronized.

SLA7032M/SLA7033M

2-Phase Stepper Motor Unipolar Driver IC (2-Phase/1-2 Phase Excitation)

)

9,(10)

3,(14)

)

9,(10)

3,(14)

Power down
signal

■

Determining the Output Current

Fig. 1 shows the waveform of the output current (motor coil cur-

rent). The method of determining the peak value of the output

current (I

) based on this waveform is shown below.

(Parameters for determining the output current I

)

: Reference supply voltage

: Voltage-divider resistors for the reference supply voltage

: Current sense resistor

(1) Normal rotation mode

is determined as follows when current flows at the maximum

level during motor rotation. (See Fig.2.)

(2) Power down mode

The circuit in Fig.3 (r

and T

) is added in order to decrease the

coil current. I

is then determined as follows.

Equation (2) can be modified to obtain equation to determine r

Fig. 4 and 5 show th e graphs of equations (1) and (2) respec-

tively.

Fig. 2 Normal mode

Phase A

Fig. 1 Waveform of coil current (Phase A excitation ON)

Fig. 3 Power down mode

Current sense resistor R

(

Ω

)

Output current I

(A)

=510

Ω

=100

Ω

∞

=5V

Fig. 4 Output current I

vs. Current sense resistor R

Fig. 5 Output current I

OPD

vs. Variable current sense resistor r

2.0

1.5

1.0

0.5

200

400

600

800

Variable current sense resistor r

(

Ω

)

Output current I

OPD

(A)

1000

1200

=0.5

Ω

=0.8

Ω

OPD

1+ R

=510

Ω

=100

Ω

=5V

)

2 ·

•

OPD

−

................................................................ (1)

≅

•

......................................................... (2)

OPD

≅

•

)

•

SLA7032M/SLA7033M

2-Phase Stepper Motor Unipolar Driver IC (2-Phase/1-2 Phase Excitation)

100

500

Case temper

ature r

ise

∆

–

(

Response frequency (pps)

Without heatsink
Natural cooling

Motor : 23PM-C705
Motor current I

=1.5A

=25

=24V, V

=24V

2-phase excitation

( 4 pin)

200

500

Case temperature rise

∆

–

(

Motor : PH265-01B
Motor current I

=0.8A

=25

=24V, V

=24V

2-phase excitation

Response frequency (pps)

Without heatsink
Natural cooling

( 4 pin)

SLA7032M

SLA7033M

Thermal characteristics

Fig. 7 Temperature rise

Fig. 6 Heat dissipation per phase P

vs. Output current I

Output current I

(A)

Heat dissipation per phase P

(W)

Motor : 23LM-C004
Holding mode

0.2

0.4

0.6

0.8

1.0

1.2

1.0

0.8

0.6

0.4

0.2

=44V

36V

24V

15V

∆

j–

∆

–

∆

Natural cooling
Without heatsink

150

100

Total Power (W)

(

Heat dissipation per phase P

(W)

Motor : 23PM-C503
Holding mode

36V

15V

24V

=44V

4.0

3.0

2.0

1.0

2.0

3.0

Output current I

(A)

SLA7032M

SLA7033M

■

Thermal Design

An outline of the method for calculated heat dissipation is shown below.

(1) Obtain the value of P

that corresponds to the motor coil current I

from Fig. 6 "Heat dissipation per phase P

vs. Output current I

(2) The power dissipation P

diss

is obtained using the following formula.

2-phase excitation: P

diss

≅

+0.015

(W)

1-2 phase excitation: P

diss

≅

+0.015

(W)

(3) Obtain the temperature rise that corresponds to the computed value of P

diss

from Fig. 7 "Temperature rise."

3
2

SDK03M

2-Phase Stepper Motor Unipolar Driver ICs

SDK03M

■

Electrical Characteristics

■

Absolute Maximum Ratings

Parameter

Symbol

Ratings

Units

min

typ

max

Control supply current

7.5

Condition

=44V

Control supply voltage

FET Drain-Source

DSS

100

voltage

Condition

=44V, I

DSS

=250

FET ON voltage

0.85

Condition

=1A, V

=14V

FET drain leakage current

DSS

Condition

DSS

=100V, V

=44V

FET diode forward

1.2

voltage

Condition

=1A

TTL input current

Condition

=2.4V, V

=44V

−

0.8

Condition

=0.4V, V

=44V

TTL input voltage

Condition

=1A

(Active High)

0.8

Condition

DSS

=100V

TTL input voltage

Condition

DSS

=100V

(Active Low)

0.8

Condition

=1A

0.5

Condition

=24V, I

=0.8A

Switching time

stg

0.7

Condition

=24V, I

=0.8A

0.1

Condition

=24V, I

=0.8A

Parameter

Symbol

Ratings

Units

Motor supply voltage

FET Drain-Source voltage

DSS

100

Control supply voltage

TTL input voltage

Reference voltage

REF

Output current

Power dissipation

2.5 (Without Heatsink)

Channel temperature

+150

Storage temperature

stg

−

40 to +150

2-Phase/1-2 Phase Excitation

DC characteristics

AC characteristics

SDK03M

2-Phase Stepper Motor Unipolar Driver ICs (2-Phase/1-2 Phase Excitation)

■

Internal Block Diagram

■

Diagram of Standard External Circuit (Recommended Circuit Constants)

Excitation input

Active H

Active L

Pin 1

OUT

Pin 16

Pin 8

OUT

Pin 9

Reg.

+
–

GND

REF

Active High

Active Low

(46V max)

Motor coil

Phase A

Motor coil
Phase B

Motor coil

Phase A

Motor coil
Phase B

(5V)

OUT

GND

REF

SDK03M

Phase A

OUT

REF

GND

SDK03M

Phase B

Active
High

(46V max)

(5V)

OUT

GND

REF

SDK03M

Phase A

OUT

REF

GND

SDK03M

Phase B

Active
Low

1, 8, 9, 16pin Description of pins

Excitation signal time chart

2-phase excitation

Phase

clock

Phase A

Phase B

1-2-phase excitation

Phase

clock

0 1 2 3 4 5 6 7 0 1 2 3

Phase A

H H L L L L L H H H L L

L L L H H H L L L L L H

Phase B

L H H H L L L L L H H H

L L L L L H H H L L L L

Excitation signal time chart

2-phase excitation

Phase

clock

Phase A

Phase B

1-2-phase excitation

Phase

clock

0 1 2 3 4 5 6 7 0 1 2 3

Phase A

L L H H H H H L L L H H

H H H L L L H H H H H L

Phase B

H L L L H H H H H L L L

H H H H H L L L H H H H

510

Ω

100

Ω

(VR)

47k

Ω

47k

Ω

2.4k

Ω

2.4k

Ω

1 :

470pF

2 :

470pF

3 :

2200pF

4 :

2200pF

1.8

Ω

typ

510

Ω

100

Ω

(VR)

47k

Ω

47k

Ω

2.4k

Ω

2.4k

Ω

1 :

470pF

2 :

470pF

3 :

2200pF

4 :

2200pF

1.8

Ω

typ

(1 to 2W)

SDK03M

2-Phase Stepper Motor Unipolar Driver ICs (2-Phase/1-2 Phase Excitation)

)

13 15

)

Power down
signal

13 15

■

Determining the Output Current

Fig. 1 shows the waveform of the output current (motor coil cur-

rent). The method of determining the peak value of the output

current (I

) based on this waveform is shown below.

(Parameters for determining the output current I

)

: Reference supply voltage

: Voltage-divider resistors for the reference supply voltage

: Current sense resistor

(1) Normal rotation mode

is determined as follows when current flows at the maximum

level during motor rotation. (See Fig.2.)

(2) Power down mode

The circuit in Fig.3 (r

and T

) is added in order to decrease the

coil current. I

is then determined as follows.

Equation (2) can be modified to obtain equation to determine r

Fig. 4 and 5 show the graphs of equations (1) and (2) respec-

tively.

Fig. 2 Normal mode

Phase A

Fig. 1 Waveform of coil current (Phase A excitation ON)

Fig. 3 Power down mode

Current sense resistor R

(

Ω

)

Output current I

(A)

=510

Ω

=100

Ω

∞

=5V

Fig. 4 Output current I

vs. Current sense resistor R

Fig. 5 Output current I

OPD

vs. Variable current sense resistor r

2.0

1.5

1.0

0.5

200

400

600

800

Variable current sense resistor r

(

Ω

)

Output current I

OPD

(A)

1000

1200

=0.5

Ω

=0.8

Ω

OPD

1+ R

=510

Ω

=100

Ω

=5V

)

2 ·

Application Notes

•

OPD

−

(NOTE)

Ringing noise is produced in the current sense resistor R

when

the MOSFET is switched ON and OFF by chopping. This noise

is also generated in feedback signals from R

which may there-

fore cause the comparator to malfunction. To prevent chopping

malfunctions, r

) and C

) are added to act as a noise filter.

However, when the values of these constants are increased,

the response from R

to the comparator becomes slow. Hence

the value of the output current I

is somewhat higher than the

calculated value.

................................................................ (1)

≅

•

......................................................... (2)

OPD

≅

•

)

•

SDK03M

2-Phase Stepper Motor Unipolar Driver ICs (2-Phase/1-2 Phase Excitation)

10 12

30
35
40

Motor coil resistance R

(

Ω

)

ON time T

( s)

=36V

Chopping frequency f (kHz)

OFF

=12 s

Ω

=1~3ms

= =

47k

Ω

500pF

Fig. 6 Chopper frequency vs. Motor coil resistance

■

Determining the chopper frequency

Determining T

OFF

SDK03M is self-excited choppers. The chopping OFF time T

OFF

is fixed by r

and r

connected to terminal T

OFF

can be calculated using the following formula:

The circuit constants and the T

OFF

value shown below are rec-

ommended.

OFF

= 12

s at r

=47k

Ω

, C

=500pF, V

=5V

■

Chopper frequency vs. Supply voltage

■

Chopper frequency vs. Output current

f (kHz)

(V)

Motor : 23LM-C202

= 0.8A at V

=24V

Ω

f (kHz)

(A)

0.2

0.4

0.6

0.8

1.0

Motor : 23LM-C202

=24V

Ω

OFF

≅−

•

1 n

−

•

−

)

SDK03M

2-Phase Stepper Motor Unipolar Driver ICs (2-Phase/1-2 Phase Excitation)

■

Supply Voltage V

vs. Supply Current I

■

Torque Characteristics

Supply current I

(mA)

Supply voltage V

(V)

500

400

300

200

100

Motor : 23LM-C202
1-phase excitation
Holding mode
I

: Output current

=1A

0.4A
0.2A

100

Pull-out torque (kg-cm)

Response frequency (pps)

2.0

1.5

1.0

0.5

500

Motor : PX244-02
Output current I

=0.6A

Motor supply voltage V

=24V

2-phase excitation

1.2

0.8

0.6

0.4

0.2

0.4

0.6

0.8

1.0

Heat dissipation per phase P

(W)

Output current I

(A)

36V

24V

15V

=44V

Motor : 23LM-C202
Holding mode

Fig. 7 Heat dissipation per phase P

vs. Output current I

∆

Glass epoxy board
(mounted on level surface)
(95

1.2mm)

Natural cooling

150

100

Total power (W)

∆

j–

∆

–

(

200

500

Case temperature rise

∆

–

(

Response frequency (pps)

( 9 pin)

Natural cooling
Glass epoxy board
(mounted on level surface)
(95

1.2mm)

Motor : PH265-01B
Motor current I

=0.8A

=25

=24V, V

=24V

2-phase excitation

Thermal characteristics

Fig. 8 Temperature rise

Active Low

Input

Corresponding output

(pin6)

OUT

(pin8, 9)

(pin5)

OUT

(pin1, 16)

Active High

Input

Corresponding output

(pin6)

OUT

(pin1, 16)

(pin5)

OUT

(pin8, 9)

■

Note

The excitation input signals of the SDK03M can be used as either Active High or Active Low. Note, However, that the corresponding

output (OUT) changes depending on the input (IN).

■

Thermal Design

An outline of the method for computing heat dissipation is shown below.

(1) Obtain the value of P

that corresponds to the motor coil current

from Fig. 7 "Heat dissipation per phase P

vs. Output current

(2) The power dissipation Pdiss is obtained using the following formula.

2-phase excitation: P

diss

≅

+0.0075

(W)

1-2 phase excitation: P

diss

≅

+0.0075

(W)

(3) Obtain the temperature rise that corresponds to the calcu-

lated value of P

diss

from Fig. 8 "Temperature rise."

3
4

UCN5804B

2-Phase Stepper Motor Unipolar Driver IC

UCN5804B

Allegro MicroSystems product

■

Features

●

Internal 1-phase/1-2 phase/2-phase excita-

tion pattern generator

●

Output enable and direction control

●

Power-on reset

●

Internal thermal shutdown circuitry

●

Internal transient-suppression diodes

●

Low thermal resistance 16-pin DIP

■

Electrical Characteristics

Parameter

Symbol

Conditions

Limits

Units

min

typ

max

Output drivers

Output leakage current

CEX

=50V

Output sustaining voltage

CE (SUS)

=1.25A, L=3mH

3.5

=700mA

1.0

1.2

Output saturation voltage

CE (SAT)

=1A

1.1

1.4

=1.25A

1.2

1.5

Clamp diode leakage current

=50V

Clamp diode forward voltage

=1.25A

1.5

3.0

Turn-on delay

50% step inputs to 50% output

Turn-off delay

OFF

50% step inputs to 50% output

Thermal shutdown temperature

165

Control logic

Input current

0.5

5.0

=0.8V

−

0.5

−

5.0

Input voltage

=5V

3.5

5.3

−

0.3

0.8

Supply current

2 outputs ON

Data setup time

s DAT (A)

Inter-clock

100

Data hold time

h DAT (B)

Inter-clock

100

Clock pulse width

w CLK (C)

500

●

"typ" values are for reference.

Absolute Maximum Ratings

Parameter

Symbol

Ratings

Units

Output voltage

Output sustaining voltage

CE (SUS)

Output current (1 circuit)

1.5

A/unit

Logic supply voltage

7.0

Input voltage

7.0

Package power dissipation

(Note1)

2.90

W/pkg

Operating temperature

−

20 to +85

Junction temperature

(Note2)

+150

Storage temperature

stg

−

55 to +150

Note 1: When ambient temperature is 25

C or over, derate using

−

23.3mW/

Note 2: Fault conditions where junction temperature (T

) exceeds 150

C will activate the device's thermal

shutdown circuitry. These conditions can be tolerated but should be avoided.

(Unless specified otherwise, T

=25

C, V

=4.5V to 5.5V)

=+25

(Unless specified otherwise, V

or GND)

■

Terminal Connection Diagram

■

Timing Conditions

OUTPUT

GROUND

SUPPLY

DIRECTION

OUTPUT
ENABLE

GROUND

HALF-STEP

ONE-PHASE

STEP INPUT

GROUND

LOGIC

CLOCK

ONE PHASE

HALF-STEP

OUTPUT

OUTPUT
ENABLE

TWO-PHASE

HALF-STEP

OUTPUT
DISABLED

WAVE DRIVE

2-Phase/1-2 Phase Excitation

SLA7042M/SLA7044M

2-Phase Stepper Motor Unipolar Driver ICs

SLA7042M/SLA7044M

Parameter

Symbol

Ratings

Units

SLA7042M

SLA7044M

Motor supply voltage

FET Drain-Source voltage

DSS

100

Control supply voltage

Input voltage

−

0.5 to V

+0.5

Output current

1.2

Power dissipation

4.5 (Without Heatsink)

Channel temperature

+150

Storage temperature

stg

−

40 to +150

■

Absolute Maximum Ratings

■

Electrical Characteristics

Terminals
DATA,
CLOCK
and
STROBE

Ratings

Parameter

Symbol

SLA7042M

SLA7044M

Units

min

typ

max

min

typ

max

Control supply current

Conditions

=5.5V

Control supply voltage

4.5

5.5

4.5

5.5

3.5

Conditions

=5V

1.5

Conditions

=5V

Conditions

=5V

Conditions

=5V, V

=0 or 5V

=5V, V

=0 or 5V

REF

0.4

2.5

0.4

2.5

Conditions

=5V

REF

DISABLE

−

terminal

Conditions

=5V

REF

Conditions

=5V, V

=0 or 5V

=5V, V

=0 or 5V

ref

Conditions

MODE 0

ref

Conditions

MODE 1

ref

Conditions

MODE 2

ref

55.5

Reference voltage

Conditions

MODE 3

selection output voltage

ref

71.4

Conditions

MODE 4

ref

Conditions

MODE 5

ref

Conditions

MODE 6

ref

100

Conditions

MODE 7

FET ON voltage

0.8

1.4

Conditions

=1.2A, V

=4.75V

=3A, V

=4.75V

FET Drain-Source

DSS

100

voltage

Conditions

DSS

=4mA, V

=5V

DSS

=4mA, V

=5V

FET drain leakage current

DSS

Conditions

DSS

=100V, V

=5V

DSS

=100V, V

=5V

FET diode forward voltage

1.2

2.3

Conditions

=1.2A

=3A

OFF

Conditions

MODE 1, 2

Chopper off time

OFF

Conditions

MODE 3, 4, 5

OFF

Conditions

MODE 6, 7

0.5

Conditions

=5V, I

=1A

=5V, I

=1A

Switching time

stg

0.7

Conditions

=5V, I

=1A

=5V, I

=1A

0.1

Conditions

=5V, I

=1A

=5V, I

=1A

Data setup time "A"

DAT

Conditions

Inter-clock

Data hold time "B"

DAT

Conditions

Inter-clock

Data pulse time "C"

DAT

150

Conditions

Clock pulse width "D"

twh

CLK

100

Conditions

Stabilization time

tps

STB

100

before strobe "E"

Conditions

Strobe=L from clock

Strobe pulse H width "F"

twh

STB

100

Conditions

2W1-2 Phase Excitation/Micro-step Support

Input
voltage

Input hysteresis
voltage
Input
current

Input
voltage

Input
current

DC characteristics

AC characteristics

SLA7042M/SLA7044M

2-Phase Stepper Motor Unipolar Driver ICs (2W1-2 Phase Excitation/Micro-step Support)

SLA7042M/SLA7044M

■

Internal Block Diagram

■

Diagram of Standard External Circuit

■

Output Current Formula

K: Reference voltage setting rate by serial signal

(See the internal block diagram)

•

REF

3 R

B OUT A

OUT A OUT B

OUT B

REF A

REF B

GND A GND B

RS A

RS B

REF

ENABLE

CLOCK A

CLOCK B

STROBE A

STROBE B

DATA A

DATA B

: 500 to 10000pF

SLA7042M
SLA7044M

OUT A

VDD A

VDD B

OUT B

Rs B

GND B

Ref B

Ref A

GND A

Rs A

ATA

CLOCK B

OUT B

CLOCK A

STR

OBE B

STR

OBE A

Enable

COMP

Phase

Vref

20%
40%

55.5%
71.4%

83%
91%

100%

a
0
1
0
1
0
1
0
1

PWM

Reset

Ph.

Reset

Enable

COMP

Phase

PWM

Reset

OFF time timer

(TOFF 3-step switching)

Chopper ON

Noise filter

(2 s)

Latch

Reference voltage

Ph.

Shift register

Ph.

Latch

Ph.

Shift register

b
0
0
1
1
0
0
1
1

c
0
0
0
0
1
1
1
1

b
0
0
1
1
0
0
1
1

a
0
1
0
1
0
1
0
1

Vref

20%
40%

55.5%
71.4%

83%
91%

100%

OFF time timer

(TOFF 3-step switching)

Chopper ON

Noise filter

(2 s)

SLA7042M/SLA7044M

2-Phase Stepper Motor Unipolar Driver ICs (2W1-2 Phase Excitation/Micro-step Support)

SLA7042M/SLA7044M

■

External Dimensions

(Unit: mm)

0.2

24.4

0.2

16.4

0.2

3.2

0.15

x3.8

+0.2

−

0.1

0.65

+0.2

−

0.1

17xP1.68

0.4

=28.56

31.3

0.2

1 2 3

• • • • • • • • • • • •

3.2

0.15

Part No.

Lot No.

0.2

9.9

0.2

Forming No. No.871

4.8

0.2

1.7

0.1

2.45

0.2

R-End

0.7

0.55

+0.2

−

0.1

(3)

6.7

0.5

9.7

+0.2

−

0.1

17xP1.68

0.4

=28.56

+0.2

−

0.1

0.65

+0.2

−

0.1

7.5

0.6

2.2

0.1

0.55

+0.2

−

0.1

1.6

0.6

4.6

0.6

1 2 3

• • • • • • • • • • • •

Forming No. No.872

Successively output this serial data and set any current. Then, determine the step

time of the reference voltage V

ref

at STROBE signal intervals.

■

Serial Data Pattern

See page 48 for details of
PG001M serial signal gen-
erator IC for SLA7042M and
SLA7044M.

OUT excitation (MODE

)

OUT excitation (MODE

)

CLOCK

STROBE

MODE0

(0%)

MODE1

(20%)

MODE2

(40%)

MODE3

(55.5%)

MODE4

(71.4%)

MODE5

(83%)

MODE6

(91%)

MODE7

(100%)

DATA

Phase

SLA7042M/SLA7044M

2-Phase Stepper Motor Unipolar Driver ICs (2W1-2 Phase Excitation/Micro-step Support)

SLA7042M/SLA7044M

■

Current Vector Locus (One step of stepper motor normalized to 90 degrees)

55.5

71.4 83 91

100

To rotate the motor, enter serial data as follows:
2W1-2 phase excitation
W1-2 phase excitation
1-2 phase excitation
2-2 phase excitation

: Vector 1

→

9 ...

: Vector 1

→

....

: Vector 1

→

: Vector 5 or 10

Combined

Current A Current B

vector

100%

20%

91%

40%

83%

55.5%

71.4%

55.5%

83%

40%

91%

20%

100%

Sequence

DATA-A

MODE

DATA-B

MODE

■

Serial Data Sequence Example (2W 1-2 Phase Excitation for CW)

A malfunction may occur just after the power (V

) is turned on because the internal logic is unstable. Therefore, set

the RESET state (REF terminal voltage: V

−

1V to V

) after the power is turned on.)

■

Operation Current Waveform Examples

Torque-up waveform at start

Stationary waveform

Leading phase waveform at acceleration

Start

Time

These three types of waveforms can all be set with a serial signal.

PG001M

Serial Signal Generator IC for SLA7042M and SLA7044M

PG001M

CLOCK_IN

CLOCK_OUT

DATA

STROBE

1/F

CLOCK_OUT
DATA
STROBE

90%

10%

CLOCK_IN

RESET

MS1

MS2

CW/CCW

Excitation switching point

VC switching occurs only while CLOCK-IN level is L.

Fig. 1

Fig. 3 Timing conditions

Fig.2

=25

Parameter

Symbol

Conditions

Ratings

Units

min

typ

max

Supply voltage

4.5

5.5

Supply current

=5.5V

0.35

0.45

Output voltage

=5V, I

3mA

4.5

0.4

Input current

=5V, V

=0 or 5V

Input voltage

=5V

3.5

−

0.3

1.5

Input hysteresis voltage

=5V

Input capacity

=5V

Internal oscillation frequency

=5V

1.5

MHz

Propagation delay time

See Fig. 1.

100

430

550

Output voltage

=5V, C

=15pF

Rise and fall time

See Fig. 2.

CLOCK IN terminal

CIH

H level time, V

=5V

4.5

Input clock time

CIL

L level time, V

=5V

0.5

Reset setting time (A)

Inter-clock

100

Stabilization time after reset (B)

tps

See Fig. 3.

Signal setting time (C)

Inter-clock

Stabilization time after

tps

See Fig. 3.

100

signal input (D)

Parameter

Symbol

Ratings

Units

Supply voltage

−

0.5 to 7

Input voltage

−

0.5 to V

+0.5

Input current

Output voltage

−

0.5 to V

+0.5

Output current

Power dissipation

200

Operating temperature

−

20 to +85

Storage temperature

stg

−

40 to +150

■

Absolute Maximum Ratings

=25

■

Electrical Characteristics

DC characteristics

AC characteristics

PG001M

Serial Signal Generator IC for SLA7042M and SLA7044M

■

Input and Output Function Correlation Table

Input

Output

Mode

RESET

STROBE

CLOCK
_IN

CW
/CCW

CLOCK
_OUT

DATA
-A

CCW

RESET

CCW

DATA
-B

Output Mode

4 or 7

Output

Mode

Input Mode

4 or 7

Output

Mode

: Don't care

∗

: MO outputs L level while CLOCK_IN

is H level when output mode is 4:4

(7:7), 4:4 (7:7), 4:4 (7:7),or 4:4 (7:7).

Modes in brackets ( ) are for 2-2

phase VC: H.

■

Excitation Selection Table

■

Output Mode Sequence

Excitation method

Input

−

MS1 MS2

0% 20% 40% 55.5% 71.4% 83% 91% 100%

141%

100%

Output current mode of SLA7042M/7044M

Excitation mode

selection

Torque vector

2-2 Phase

Full Step

1-2 Phase

Half Step

W1-2 Phase

1/4 Step

2W1-2 Phase

1/8 Step

Excitation

method

2-2 Phase

Full Step (1)

(VC: H)

2-2 Phase

Full Step (2)

(VC: L)

1-2 Phase

Half Step

W1-2 Phase

1/4 Step

2W1-2 Phase

1/8 Step

CLOCK

DATA_A

DATA_B

DATA_A

DATA_B

DATA_A

DATA_B

DATA_A

DATA_B

DATA_A

DATA_B

DATA_A

DATA_B

DATA_A

DATA_B

DATA_A

DATA_B

DATA_A

DATA_B

DATA_A

DATA_B

CW/CCW

CCW

RESET

= : No output

A3966SA/SLB

2-Phase Stepper Motor Bipolar Driver IC

A3966SA/SLB

Allegro MicroSystems product

■

Features

●

Maximum output ratings: 30V,

650mA

●

Internal fixed-frequency PWM current con-

trol

●

Internal ground-clamp & flyback diodes

●

Internal thermal shutdown, crossover-cur-

rent protection and UVLO protection cir-

cuitry

●

Employs copper batwing lead frame with

low thermal resistance

■

Electrical Characteristics

Parameter

Symbol

Conditions

Ratings

Units

min

typ

max

Power outputs (OUT

or OUT

)

Load supply voltage range

Operating, I

650mA, L=3mH

Output leakage current

CEX

=30V

< 1.0

=0V

−

1.0

−

Source Driver, I

−

400mA

1.7

2.0

Output saturation voltage

(sat)

Source Driver, I

−

650mA

1.8

2.1

Sink Driver, I

=+400mA, V

SENSE

=0.5V

0.3

0.5

Sink Driver, I

=+650mA, V

SENSE

=0.5V

0.4

1.3

Sense-current offset

−

, I

=50~650mA

Clamp diode forward voltage

=400mA

1.1

1.4

=650mA

1.4

1.6

Motor supply current (No load)

(ON)

ENABLE1

ENABLE2

=0.8V

3.0

5.0

(OFF)

ENABLE1

ENABLE2

=2.4V

< 1.0

200

Control logic

Logic supply voltage range

Operating

4.75

5.50

Logic input voltage

2.4

0.8

Logic input current

=2.4V

< 1.0

=0.8V

−

200

Reference input voltage range

REF

Operating

0.1

2.0

Reference input current

REF

−

2.5

1.0

Reference divider ratio

REF

TRIP

3.8

4.0

4.2

Current-sense comparator input offset voltage

REF

=0V

−

6.0

Current-sense comparator input voltage range

Operating

−

0.3

1.0

PWM RC frequency

OSC

=680pF, R

=56k

Ω

22.9

25.4

27.9

kHz

PWM propagation delay time

PWM

Comparator Trip to Source OFF

1.0

1.4

Cycle Reset to Source ON

0.8

1.2

Cross-over dead time

codt

Ω

Load to 25V

0.2

1.8

3.0

650mA, 50% to 90% : ENABLE ON to Source ON

100

650mA, 50% to 90% : ENABLE OFF to Source OFF

500

650mA, 50% to 90% : ENABLE ON to Sink ON

200

Propagation delay time

650mA, 50% to 90% : ENABLE OFF to Sink OFF

200

650mA, 50% to 90% : PHASE Change to Sink ON

2200

650mA, 50% to 90% : PHASE Change to Sink OFF

200

650mA, 50% to 90% : PHASE Change to Source ON

2200

650mA, 50% to 90% : PHASE Change to Source OFF

200

Thermal shutdown temperature

165

Thermal shutdown hysteresis

∆

UVLO enable threshold

UVLO en

Increasing V

4.1

4.6

UVLO hysteresis

UVLO hys

0.1

0.6

Logic supply current

(ON)

ENABLE1

ENABLE2

=0.8V

(OFF)

ENABLE1

ENABLE2

=2.4V

●

"typ" values are for reference.

■

Absolute Maximum Ratings

Parameter

Symbol

Ratings

Units

A3966SA

A3966SLB

Load supply voltage

Output current (peak)

(Peak)

750

Output current (continuous)

650

Logic supply voltage

7.0

Logic input voltage range

−

0.3 to V

+0.3

Sense voltage

1.0

Package power dissipation

(Note1)

2.08

1.86

Ambient operating temperature

−

20 to +85

Junction temperature

(Note2)

+150

Storage temperature

stg

−

55 to +150

●

Output current rating may be limited by duty cycle, ambient temperature, and heat sinking. Under any
set of conditions, do not exceed the specified current rating or a junction temperature of 150

Note 1: When ambient temperature is 25

C or over, derate using

−

16.67mW/

C (SA),

−

14.93mW/

C (SLB).

Note 2: Fault conditions where junction temperature (T

) exceeds 150

C will activate the device's thermal

shutdown circuitry. These conditions can be tolerated but should be avoided.

(Unless specified otherwise, T

=25

C, V

=30V, V

=4.75V to 5.5V, V

REF

=2V, V

= 0V, 56k

Ω

& 680pF RC to ground)

2-Phase/1-2 Phase Excitation

A3966SA/SLB

2-Phase Stepper Motor Bipolar Driver IC (2-Phase/1-2 Phase Excitation)

A3966SA/SLB

■

Derating

Allowable package power dissipation P

[W]

0.5

1.5

2.5

Ambient temperature Ta (

−

75 85 100

A3966SLB 67

C/W

A3966SA 60

C/W

■

Internal Block Diagram (1/2 circuit)

PHASE

ENABLE

(ACTIVE LOW)

GROUND

OSC

−

TO OTHER
BRIDGE

BLANKING
GATE

PWM LATCH

CURRENT-SENSE
COMPARATOR

SENSE

UVLO

& TSD

LOGIC

SUPPL

OUT

REFERENCE

■

Truth Table

■

Load-Current Paths

PHASE

ENABLE

OUT

X: Don't care (either L or H)

Z: High impedance (source and sink both OFF)

BRIDGE ON

SOURCE OFF

ALL OFF

■

Terminal Connection Diagram

LOGIC

OUT

PHASE

ENABLE

GROUND

SENSE

OUT

LOAD

SUPPLY

REFERENCE

OUT

PHASE

ENABLE

GROUND

SENSE

OUT

REF

LOGIC
SUPPLY

LOGIC

OUT

PHASE

ENABLE

SENSE

OUT

LOAD

SUPPLY

REFERENCE

OUT

PHASE

ENABLE

GROUND

SENSE

OUT

REF

LOGIC

SUPPLY

A3966SA

A3966SLB

A3964SLB

2-Phase Stepper Motor Bipolar Driver IC

A3964SLB

Allegro MicroSystems product

■

Features

●

Fixed off-time PWM current control

●

Internally generated, precision 2.5V refer-

ence

●

External filter for sense terminal not required

●

Internal thermal shutdown circuitry

●

Internal crossover-current protection cir-

cuitry

●

Internal UVLO protection

●

Internal transient-suppression diodes

●

Low thermal resistance 20-pin SOP

■

Absolute Maximum Ratings

Parameter

Symbol

Ratings

Units

Load supply voltage

Output current (continuous)

0.80

Logic supply voltage

7.0

Logic input voltage range

−

0.3 to V

+0.3

Continuous output emitter voltage

1.0

Reference output current

REF-OUT

1.0

Package power dissipation

(Note1)

2.08

Operating temperature

−

20 to +85

Junction temperature

(Note2)

+150

Storage temperature

stg

−

55 to +150

●

Output current rating may be limited by duty cycle, ambient temperature, and heat sinking. Under any
set of conditions, do not exceed the specified current rating or a junction temperature of 150

Note 1: When ambient temperature is 25

C or over, derate using

−

16.7mW/

Note 2: Fault conditions where junction temperature (T

) exceeds 150

C will activate the device's thermal

shutdown circuitry. These conditions can be tolerated but should be avoided.

Parameter

Symbol

Conditions

Ratings

Units

min

typ

max

Power outputs (OUT

or OUT

)

Load supply voltage range

Operating

Output leakage current

CEX

Sink driver, V

< 1.0

Source driver, V

=0V

−

1.0

−

Sink driver, I

=+500mA

0.3

0.6

Sink driver, I

=+750mA

0.5

1.2

Output saturation voltage

CE (SAT)

Sink driver, I

=+800mA

1.5

Source driver, I

−

500mA

1.0

1.2

Source driver, I

−

750mA

1.1

1.5

Source driver, I

−

800mA

1.7

Output sustaining voltage

CE (SUS)

800mA, L=3mH

Clamp diode leakage current

=30V

< 1.0

Clamp diode forward voltage

=800mA

1.6

2.0

Motor supply current

BB (ON)

EN1

EN2

=0.8V, no load

BB (OFF)

EN1

EN2

=2.4V, no load

Control logic

Logic input voltage

2.4

0.8

Logic input current

=2.4V

−

1.0

=0.8V

−

200

Reference output voltage

REF

•

OUT1

=5.0V, I

REF

•

OUT

=90~900

2.45

2.50

2.55

Current-sense comparator input current

REF

•

REF

•

=1V

−

5.0

Current-sense comparator input voltage range

REF

•

Operating

−

0.3

1.0

Current-sense comparator input offset voltage

REF

•

=0V

−

Timer blanking charge current (RC off)

=2.0V

1.0

Timer blanking threshold (RC off)

BLTH(1)

3.0

BLTH(0)

1.0

Timer blanking OFF voltage (RC off)

RCOFF

=20k

Ω

3.0

Thermal shutdown temperature

165

Thermal shutdown hysteresis

∆

Logic supply current

CC (ON)

EN1

EN2

=0.8V, no load

CC (OFF)

EN1

EN2

=2.4V, no load

Logic supply current/temperature coefficient

∆

CC (ON)

EN1

EN2

=0.8V, no load

0.18

mA/

●

"typ" values are for reference.

Note) Logic input: En1, En2, Ph1, Ph2

(Unless specified otherwise, V

or GND)

OUT

GROUND

PHASE

ENABLE

REF

SENSE

OUT

GROUND

PHASE

ENABLE

REF

OUT

SENSE

2.5

1.5

1.0

0.5

2.0

−

100

Ambient temperature Ta (

Allo

le pac

kage po

r dissipation P

D (

■

Terminal Connection Diagram

■

Derating

2-Phase/1-2 Phase Excitation

■

Electrical Characteristics

(Unless specified otherwise, T

=25

C, V

=30V, V

=4.75V to 5.25V, V

REF

=2V, V

SENSE

= 0V)

A3964SLB

2-Phase Stepper Motor Bipolar Driver IC (2-Phase/1-2 Phase Excitation)

A3964SLB

■

External Dimensions

Wide body plastic SOP (300mil)

■

Internal Block Diagram(Dotted Line)/

Diagram of Standard External Circuit (Recommended Circuit Constants)

■

Excitation Sequence

[1-2 phase excitation]

(Unit: mm)

[2-phase excitation]

■

Truth Table

ICs per stick

Phase

Phase 1

Enable 1

Enable 2

Phase 2

Phase 1

Enable 1

Enable 2

Phase 2

Enable

Out A

Out B

X = Don't care, Z = High impedance

−

Blanking time &

one shot multi

Blanking time &

one shot multi

=20k

Ω

=5k

Ω

(VR)

=30k

Ω

=1000pF

=0.68 to 1.5

Ω

(1 to 2W)

(5~30V)

(5V)

Sen

REF

Sen

GND

OUT

Phase 2

Enable 2

Source off

TSD

Phase 1

Enable 1

Source off

1.27
0.40

0.32
0.23

10.65
10.00

7.60
7.40

13.00
12.60

0.51
0.33

2.65
2.35

SEATING PLANE

0.10 MIN

1.27
BSC

TO 8

OUT

Note) [Pin] material : copper
Surface treatment : solder plating
Note) Package index may be *1.

Reference voltage

power supply

A3953SB/SLB

2-Phase Stepper Motor Bipolar Driver ICs

A3953SB/SLB

■

Terminal Connection Diagram

MODE

GROUND

LOGIC

SUPPLY

PHASE

GROUND

SENSE

LOAD
SUPPLY

BRAKE

REF

LOAD
SUPPLY

OUT

ENABLE

LOGIC

A3953SLB

A3953SB

MODE

GROUND

LOGIC

SUPPLY

PHASE

GROUND

SENSE

LOAD
SUPPLY

BRAKE

REF

LOAD
SUPPLY

OUT

ENABLE

■

Absolute Maximum Ratings

Parameter

Symbol

Ratings

Units

A3953SB

A3953SLB

Load supply voltage

Output current (continuous)

1.3

A/unit

Logic supply voltage

7.0

Logic/reference input

−

0.3 to V

+0.3

voltage range

Sense voltage

SENSE

D.C.

1.0 (V

=5.0V)

0.4 (V

=3.3V)

Package power dissipation P

(Note1)

2.90

1.86

W/pkg

Operating temperature

−

20 to +85

Junction temperature

(Note2)

+150

Storage temperature

stg

−

55 to +150

●

Output current rating may be limited by duty cycle, ambient temperature, and heat sinking. Under any
set of conditions, do not exceed the specified current rating or a junction temperature of 150

Note 1: When ambient temperature is 25

C or over, derate using

−

23.26mW/

C(SB) or

−

14.93mW/

C(SLB).

Note 2: Fault conditions where junction temperature (T

) exceeds 150

C will activate the device’s thermal

shutdown circuitry. These conditions can be tolerated but should be avoided.

■

Features

●

Fixed off-time PWM current control

●

Switching between power supply regenera-

tion mode and loop regeneration mode in

order to improve motor current response in

microstepping

●

External filter for sense terminal not required

●

3.3V and 5V logic supply voltage

●

Sleep (low current consumption) mode

●

Brake operation with PWM current limiting

●

Internal thermal shutdown circuitry

●

Internal crossover-current protection cir-

cuitry

●

Internal UVLO protection

●

Internal transient-suppression diodes

●

Low thermal resistance package

Allegro MicroSystems product

2-Phase/1-2 Phase Excitation

A3953SB/SLB

2-Phase Stepper Motor Bipolar Driver ICs (2-Phase/1-2 Phase Excitation)

A3953SB/SLB

■

Electrical Characteristics

Parameter

Symbol

Conditions

Limits

Units

min

typ

max

Power outputs (OUT

or OUT

)

Load supply voltage range

Operating, I

1.3A, L=3mH

Output leakage current

CEX

<1.0

=0V

−

1.0

−

Sense current offset

SENSE

−

, I

=850mA, V

SENSE

=0V, V

=5V

SENSE

=0.4V, V

=3.0V, BRAKE=H:Source driver, I

−

0.85A

1.0

1.1

Output saturation voltage

CE (SAT)

SENSE

=0.4V, V

=3.0V, BRAKE=H:Source driver, I

−

1.3A

1.7

1.9

(Forward/reverse mode)

SENSE

=0.4V, V

=3.0V, BRAKE=H:Sink driver, I

=0.85A

0.4

0.9

SENSE

=0.4V, V

=3.0V, BRAKE=H:Sink driver, I

=1.3A

1.1

1.3

Output saturation voltage

CE (SAT)

SENSE

=0.4V, V

=3.0V, BRAKE=L:Sink driver, I

=0.85A

1.2

1.4

(Brake mode)

SENSE

=0.4V, V

=3.0V, BRAKE=L:Sink driver, I

=1.3A

1.4

1.8

Clamp diode forward voltage

=0.85A

1.2

1.4

=1.3A

1.4

1.8

BB (ON)

ENABLE

=0.8V, V

BRAKE

=2.0V

2.5

4.0

Motor supply current

BB (OFF)

ENABLE

BRAKE

=2.0V, V

MODE

=0.8V

1.0

(No load)

BB (BRAKE)

BRAKE

=0.8V

1.0

BB (SLEEP)

ENABLE

BRAKE

MODE

=2.0V

1.0

Control logic

Thermal shutdown temperature

165

Thermal shutdown hysteresis

∆

UVLO enable threshold

UVLO

2.5

2.75

3.0

UVLO hysteresis

∆

UVLO

0.12

0.17

0.25

CC (ON)

ENABLE

=0.8V, V

BRAKE

=2.0V

Logic supply current

CC (OFF)

ENABLE

BRAKE

=2.0V, V

MODE

=0.8V

CC (BRAKE)

BRAKE

=0.8V

CC (SLEEP)

ENABLE

BRAKE

MODE

=2.0V

500

800

Logic supply voltage range

Operating

3.0

3.3

5.0

5.5

Logic input voltage

2.0

0.8

Logic input current

=2.0V

<1.0

=0.8V

−

2.0

−

200

Sense voltage range

SENSE (3.3)

=3.0V to 3.6V

0.4

SENSE (5.0)

=4.5V to 5.5V

1.0

Reference input current

REF

=0V to 1V

5.0

Comparator input offset voltage

REF

=0V

2.0

5.0

AC timing

PWM RC fixed off-time

OFF RC

=680pF, R

=30k

Ω

, V

=3.3V

18.3

20.4

22.5

PWM turn-off time

PWM (OFF)

Comparator Trip to Source OFF, Io=25mA

1.0

1.5

Comparator Trip to Source OFF, Io=1.3A

1.8

2.6

PWM turn-on time

PWM (ON)

Charge ON to Source ON, Io=25mA

0.4

0.7

Charge ON to Source ON, Io=1.3A

0.55

0.85

PWM minimum on-time

PWM (ON)

=3.3V, R

≥

12k

Ω

, C

=680pF

0.8

1.4

1.9

=5.0V, R

≥

12k

Ω

, C

=470pF

0.8

1.6

2.0

1.3A, 50% to 90% ENABLE ON to Source ON

1.0

1.3A, 50% to 90% ENABLE OFF to Source OFF

1.0

1.3A, 50% to 90% ENABLE ON to Sink ON

1.0

Propagation delay time

1.3A, 50% to 90% ENABLE OFF to Sink OFF (MODE=L)

0.8

1.3A, 50% to 90% PHASE Change to Sink ON

2.4

1.3A, 50% to 90% PHASE Change to Sink OFF

0.8

1.3A, 50% to 90% PHASE Change to Source ON

2.0

1.3A, 50% to 90% PHASE Change to Source OFF

1.7

Crossover dead time

CODT

Ω

Load to 25V, V

=50V

0.3

1.5

3.0

●

“typ” values are for reference.

(Unless specified otherwise, T

=25

C, V

=5V to 50V, V

=3.0V to 5.5V)

A3953SB/SLB

2-Phase Stepper Motor Bipolar Driver ICs (2-Phase/1-2 Phase Excitation)

A3953SB/SLB

■

Derating

■

Internal Block Diagram

■

Truth Table

■

External Dimensions

■

Application Circuit

(16-pin wide SOIC)

ENABLE

BRAKE

PHASE

MODE

Operating Mode

OUT

Sleep mode

Standby

Forward, fast current-decay mode

Forward, slow current-decay mode

Reverse, fast current-decay mode

Reverse, slow current-decay mode

Brake, fast current-decay mode

Brake, no current control

ICs per stick

X : Don't Care

Z : High impedance

LOGIC

SUPPLY

LOAD

SUPPLY

PHASE

MODE

REF

OUT

ENABLE

SENSE

−

BRAKE

GROUND

PWM LATCH

BLANKING

SLEEP &
STANDBY MODES

GROUND

LOAD

SUPPLY

INPUT LOGIC

−

UVLO

& TSD

2.0

3.0

2.5

1.5

1.0

0.5

−

100

A3953SB 43

/ W

A3953SLB 67

/ W

Ambient temperature Ta (C

)

Allowable package power dissipation P

(W)

1.27
0.40

0.32
0.23

10.65
10.00

7.60
7.40

10.50
10.10

0.51
0.33

2.65
2.35

SEATING PLANE

0.10 MIN.

1.27
BSC

TO 8

●

●
●

●

Pin material: copper,
pin surface treatment: solder plating
Package index may be *1.
Allowable variation in distance between
leads is not cumulative.
Web (batwing) type lead frames are used for
pin 4, 5, 12, 13. The pins are connected to GND.

47 F

LOGIC

30 k

Ω

0.5

Ω

MODE

PHASE

ENABLE

BRAKE

680 pF

+5 V

REF

OFF

≅

•

12k to 100k

Ω

470 to 1500pF (Operating at V

CC=

5V)

680 to 1500pF (Operating at V

CC=

3.3V)

Off-time setting

(DC motor drive)

(A3953SB)

Plastic DIP (300mil)

1.77

1.15

21.33
18.93

0.558
0.356

4.06
2.93

7.11
6.10

INDEX AREA

0.127MIN

7.62BSC

2.54BSC

5.33MAX

SEATING PLANE

0.39MIN

0.381
0.204

●

Note 1:

Thickness of lead is measured
below seating plane.
Allowable variation in distance between
leads is not cumulative.

Lead width of pin 1, 8, 9, 16 may be
half the value shown here.
Maximum thickness of lead is 0.508mm.

ICs per stick

A3953SB

A3953SLB

(Unit: mm)

A3953SB/SLB

2-Phase Stepper Motor Bipolar Driver ICs (2-Phase/1-2 Phase Excitation)

A3953SB/SLB

■

Outline

Designed for bidirectional pulse-width modulated (PWM) cur-

rent control of inductive loads, the A3953S- is capable of con-

tinuous output currents to

1.3A and operating voltages to 50V.

Internal fixed off-time PWM current-control circuitry can be used

to regulate the mximum load current to a desired value. The

peak load current limit is set by the user’s selection of an input

reference voltage and external sensing resistor. The fixed off-

time pulse duration is set by a userselected external RC timing

network. Internal circuit protection includes thermal shutdown

with hysteresis, transient-suppression diodes, and crossover cur-

rent protection. Special power-up sequencing is not required.

With the ENABLE input held low, the PHASE input controls load

current polarity by selecting the appropriate source and sink

driver pair. The MODE input determines whether the PWM cur-

rent-control circuitry operates in a slow current-decay mode (only

the selected source driver switching) or in a fast current-decay

mode (selected source and sink switching). A user-selectable

blanking window prevents false triggering of the PWM current-

control circuitry. With the ENABLE input held high, all output

drivers are disabled. A sleep mode is provided to reduce power

consumption.

When a logic low is applied to the Brake input, the braking func-

tion is enabled. This overrides ENABLE and PHASE to turn OFF

both source drivers and turn ON both sink drivers. The brake

function can be used to dynamically brake brush dc motors.

■

FUNCTIONAL DESCRIPTION

(A) Internal PWM Current Control During Forward and Re-

verse Operation.

The A3953S-contains a fixed off-time pulse-width modulated

(PWM) current-control circuit that can be used to limit the load

current to a desired value. The peak value of the current limiting

TRIP

) is set by the selection of an external current sensing re-

sistor (R

) and reference input voltage (V

REF

). The internal cir-

cuitry compares the voltage across the external sense resistor

to the voltage on the reference input terminal (REF) resulting in

a transconductance function approximated by:

where I

is the offset due to base drive current.

In forward or reverse mode the current-control circuitry limits

the load current as follows: when the load current reaches I

TRIP

the comparator resets a latch that turns off the selected source

driver or selected sink and source driver pair depending on

whether the device is operating in slow or fast current-decay

mode, respectively.

In slow current-decay mode, the selected source driver is dis-

abled; the load inductance causes the current to recirculate

through the sink driver and ground clamp diode. In fast current-

TRIP

−

SENSE

REF

DRIVE CURRENT

RECIRCULATION (SLOW-DECAY MODE)

RECIRCULATION (FAST-DECAY MODE)

Fig. 1 Load-current Paths

ENABLE

MODE

LOAD

CURRENT

TRIP

Fig. 2 Fast and Slow Current-Decay Waveforms

Application Notes

decay mode, the selected sink and source driver pair are dis-

abled; the load inductance causes the current to flow from ground

to the load supply via the ground clamp and flyback diodes.

The user selects an external resistor (R

) and capacitor (C

) to

determine the time period (t

OFF

•

) during which the drivers

remain disabled (see “RC Fixed Off-time” below). At the end of

the RC interval, the drivers are enabled allowing the load cur-

rent to increase again. The PWM cycle repeats, maintaing the

peak load current at the desired value (see figure 2).

(B)INTERNAL PWM CURRENT CONTROL DURING BRAKE-

MODE OPERATION

(1) Brake Operation-MODE Input High.

The brake circuit turns OFF both source drivers and turns ON

both sink drivers. For dc motor applications, this has the effect

of shoring the motor’s back-EMF voltage resulting in current

flow that dynamically brakes the motor. If the back-EMF volt-

age is large, and there is no PWM current limiting, the load cur-

rent can increase to a value that approaches that of a locked

rotor condition. To limit the current, when the I

TRIP

level is reaced,

the PWM circuit disables the conducting sink drivers. The en-

ergy stored in the motor’s inductance is discharged into the load

supply causing the motor current to decay.

As in the case of forward/reverse operation, the drivers are en-

abled after a time given by t

OFF

•

(see “RC Fixed Off-time”

below). Depending on the back-EMF voltage (proportional to

the motor’s decreasing speed), the load current again may in-

A3953SB/SLB

2-Phase Stepper Motor Bipolar Driver ICs (2-Phase/1-2 Phase Excitation)

A3953SB/SLB

1.05

•

on (min)

max + t

off

)

•

LOAD

[(V

−

SAT (source

sink)

)

•

on (min)

max]

−

[1.05

•

SAT (sink)

+ V

)

•

off

]

AVE

≅

TRIP BRAKE MH

SENSE

REF

PEAK BRAKE ML

LOAD

BEMF

−

off

•

crease to I

TRIP

. If so, the PWM cycle will repeat, limiting the peak

load current to the desired value.

During braking, when the MODE input is high, the peak current

limit can be approximated by:

CAUTION: Because the kinetic energy stored in the motor and

load inertia is being converted into current, which charges the

supply bulk capacitance (power supply output and

decoupling capacitance), care must be taken to ensure the ca-

pacitance is sufficient to absorb the energy without exceeding

the voltage rating of any devices connected to the motor sup-

ply.

(2) Brake Operation-MODE Input Low.

During braking, with the MODE input low, the internal current-

control circuitry is disabled. Therefore, care should be taken to

ensure that the motor’s current does not exceed the ratings of

the device. The braking current can be measured by using an

oscilloscope with a current probe connected to one of the motor’s

leads, or if the back-EMF voltage of the motor is known, ap-

proximated by:

(C) RC Fixed Off-Time.

The internal PWM current-control circuitry uses a one shot to

control the time the driver (s) remain (s) off. The one-shot time,

OFF

(fixed off-time), is determined by the selection of an exter-

nal resistor (R

) and capacitor (C

) connected in parallel from

the RC timing terminal to ground. The fixed off-time, over a range

of values of C

=470pF to 1500pF and R

=12k

Ω

to 100k

Ω

, is

approximated by:

The operation of the circuit is as follows: when the PWM latch is

reset by the current comparator, the voltage on the RC terminal

will begin to decay from approximately 0.60V

. When the volt-

age on the RC terminal reaches approximately 0.22 V

, the

PWM latch is set, thereby enabling the driver (s).

(D) RC Blanking.

In addition to determining the fixed off-time of the PWM control

circuit, the C

component sets the comparator blanking time.

This function blanks the output of the comparator when the out-

puts are switched by the internal current-control circuitry (or by

the PHASE, BRAKE, or ENABLE inputs). The comparator out-

put is blanked to prevent false over-current detections due to

reverse recovery currents of the clamp diodes, and/or switching

transients related to distributed capacitance in the load.

During internal PWM operation, at the end of the t

OFF

time, the

comparator’s output is blanked and C

begins to be charged

from approximately 0.22 V

by an internal current source of

approximately 1 mA. The comparator output remains blanked

until the voltage on C

reaches approximately 0.60 V

When a transition of the PHASE input occurs, C

is discharged

to near ground during the crossover delay time (the crossover

delay time is present to prevent simultaneous conduction of the

source and sink drivers). After the crossover delay, C

is charged

by an internal current source of approximately 1 mA. The com-

parator output remains blanked until the voltage on C

reaches

approximately 0.60V

When the device is disabled, via the ENABLE input, C

is dis-

charged to near ground. When the device is reenabled, C

charged by an internal current source of approximately 1 mA.

The comparator output remains blanked until the voltage on C

reaches approximately 0.60 V

For 3.3 V operation,

the minimum recommended value for C

is 680pF

5%.

For 5.0V operation,

the minimum recommended value for C

is 470pF

5%.

These values ensure that the blanking time is sufficient to avoid

false trips of the comparator under normal operating conditions.

For optimal regulation of the load current, the ablove values for

are recommended and the value of R

can be sized to deter-

mine t

OFF

. For more information regarding load current regula-

tion, see below.

(E) LOAD CURRENT REGULATION WITH INTERNAL PWM

CURRENT-CONTROL CIRCUITRY

When the device is operating in slow current-decay mode, there

is a limit to the lowest level that the PWM current-control cir-

cuitry can regulate load current. The limitation is the minimum

duty cycle, which is a function of the user-selected value of t

OFF

and the minimum on-time pulse t

ON (min)

max that occurs each

time the PWM latch is reset. If the motor is not rotating (as in the

case of a stepper motor in hold/detent mode, a brush dc motor

when stalled, or at startup), the worst case value of current regu-

lation can be approximated by:

where t

OFF

•

, R

LOAD

is the series resistance of the load, V

is the motor supply voltage and t

ON (min)

max is specified in the

electrical characteristics table. When the motor is rotating, the

back EMF generated will influence the above relationship. For

brush dc motor applications, the current regulation is improved.

For stepper motor applications, when the motor is rotating, the

effect is more complex. A discussion of this subject is included

in the section on stepper motors below.

The following procedure can be used to evaluate the worst-case

slow current-decay internal PWM load current regulation in the

system:

A3953SB/SLB

2-Phase Stepper Motor Bipolar Driver ICs (2-Phase/1-2 Phase Excitation)

A3953SB/SLB

100 k

Ω

20 k

Ω

1N4001

2N2222

Fig. 3 Synchronous Fixed-Frequency Control Circuit

Set V

REF

to 0 volts. With the load connected and the PWM cur-

rent control operating in slow current-decay mode, use and os-

cilloscope to measure the time the output is low (sink ON) for

the output that is chopping. This is the typical minimum ON

time (t

ON (min)

typ) for the device.

The C

then should be increased until the measured value of t

(min)

is equal to t

ON (min)

max as specified in the electrical charac-

teristics table. When the new value of C

has been set, the value

of R

should be decreased so the value for t

OFF

•

(with the

artificially increased value of C

) is equal to the nominal design

value. The worst-case load-current regulation then can be mea-

sured in the system under operating conditions.

(F) PWM of the PHASE and ENABLE Inputs.

The PHASE and ENABLE inputs can be pulse-width modulated

to regulate load current. Typical propagation delays from the

PHASE and ENABLE inputs to transitions of the power outputs

are specified in the electrical characteristics table. If the internal

PWM current control is used, the comparator blanking function

is active during phase and enable transitions. This eliminates

false tripping of the over-current comparator caused by switch-

ing transients (see “RC Blanking” above).

(1) Enable PWM.

With the MODE input low, toggling the ENABLE input turns ON

and OFF the selected source and sink drivers. The correspond-

ing pair of flyback and ground-clamp diodes conduct after the

drivers are disabled, resulting in fast current decay. When the

device is enabled the internal current-control curcuitry will be

active and can be used to limit the load current in a slow cur-

rent-decay mode.

For applications that PWM the ENABLE input and desire the

internal current-limiting circuit to function in the fast decay mode,

the ENABLE input signal should be inverted and connected to

the MODE input. This prevents the device from being switched

into sleep mode when the ENABLE input is low.

(2) Phase PWM.

Toggling the PHASE terminal selects which sink/source pair is

enabled, producing a load current that varies with the duty cycle

and remains continuous at all times. This can have added ben-

efits in bidirectional brush dc servo motor applications as the

transfer function between the duty cycle on the PHASE input

and the average voltage applied to the motor is more linear

than in the case of ENABLE PWM control (withch produces a

discontinuous current at low current levels). For more informa-

tion see “DC Motor Applications” below.

(3) Synchronous Fixed-Frequency PWM.

The internal PWM current-control circuitry of multiple A3953S-

devices can be synchronized by using the simple circuit shown

in figure 3. A 555IC can be used to generate the reset pulse/

blanking signal (t

) for the device and the period of the PWM

cycle (t

). The value of t

should be a minimum of 1.5ms. When

used in this configuration, the R

and C

components should be

omitted. The PHASE and ENABLE inputs should not be PWM

with this circuit configuration due to the absence of a blanking

function synchronous with their transitions.

(G)Miscellaneous Information.

A logic high applied to both the ENABLE and MODE terminals

puts the device into a sleep mode to minimize current consump-

tion when not in use.

An internally generated dead time prevents crossover currents

that can occur when switching phase or braking.

Thermal protection circuitry turns OFF all drivers should the junc-

tion termperature reach 165

C (typical). This is intended only to

protect the device from failures due to excessive junction tem-

peratures and should not imply that output short circuits are

permitted. The hysteresis of the thermal shutdown circuit is ap-

proximately 8

■

APPLICATION NOTES

(A)Current Sensing.

The actual peak load current (I

PEAK

) will be above the calculated

value of I

TRIP

due to delays in the turn off of the drivers. The

amount of overshoot can be approximated by:

where V

is the motor supply voltage, V

BEMF

is the back-EMF

voltage of the load, R

LOAD

and L

LOAD

are the resistance and in-

ductance of the load respectively, and t

PWM (OFF)

is specified in

the electrical characteristics table.

The reference terminal has a maximum input bias current of

A. This current should be taken into account when deter-

mining the impedance of the external circuit that sets the refer-

ence voltage value.

To minimize current-sensing inaccuracies caused by ground

trace I

•

R drops, the current-sensing resistor should have a sepa-

rate return to the ground terminal of the device. For low-value

sense resistors, the I

•

R drops in the printed wiring board can be

significant and should be taken into account. The use of sock-

ets should be avoided as their contact resistance can cause

variations in the effective value of R

Generally, larger values of R

reduce the aforementioned ef-

fects but can result in excessive heating and power loss in the

LOAD

BB-

[(I

TRIP

•

LOAD

) + V

BEMF

])

•

PWM (OFF)

A3953SB/SLB

2-Phase Stepper Motor Bipolar Driver ICs (2-Phase/1-2 Phase Excitation)

A3953SB/SLB

Fig. 4 Example of Circuit (including GND) and GND Wiring Pattern

TAB

+ (I

LOAD

•

)

Use jumper wiring
for dotted line.

A3953SLB

4, 5,

12, 13

REF

SENSE

GND

Vref

OUT

GND

Phase

Enable

Mode

1Pin

A3953SLB

sense resistor. The selected value of R

should not cause the

absolute maximum voltage rating of 1.0V (0.4V for

=3.3Voperation), for the SENSE terminal, to be exceeded.

The current-sensing comparator functions down to ground al-

lowing the device to be used in microstepping, sinusoidal, and

other varying current-profile applications.

(B) Thermal Considerations.

For reliable operation it is recommended that the maximum junc-

tion termperature be kept below 110

C to 125

C. The junction

termperature can be measured best by attaching a thermocouple

to the power tab/batwing of the device and measuring the tab

temperature, T

TAB

. Tthe junction temperature can then be ap-

proximated by using the formula:

where V

may be chosen from the electrical specification table

for the given level of I

LOAD

. The value for R

is given in the

package thermal resistance table for the appropriate package.

The power dissipation of the batwing packages can be improved

by 20% to 30% by adding a section of printed circuit board cop-

per (typically 6 to 18 square centimeters) connected to the

batwing terminals of the device.

The thermal performance in applications that run at high load

currents and/or high duty cycles can be improved by adding

external diodes in parallel with the internal diodes. In internal

PWM slow-decay applications, only the two ground clamp di-

odes need be added. For internal fast-decay PWM, or external

PHASE or ENABLE input PWM applications, all four external

diodes should be added for maximum junction temperature re-

duction.

(C)PCB Layout.

The load supply terminal, V

should be decoupled with an elec-

trolytic capacitor (>47

F is recommeded) placed as close to the

device as is physically practical. To minimize the elffect of sys-

tem ground I

•

R drops on the logic and reference input signals,

the system ground should have a low-resistance return to the

motor supply voltage.

See also “Current Sensing” and “Thermal Considerations” above.

(D)Fixed Off-Time Selection.

With increasing values of t

OFF

, switching losses will decrease,

low-level load-current regulation will improve, EMI will be re-

duced, the PWM frequency will decrease, and ripple current will

increase. The value of t

OFF

can be chosen for optimization of

these parameters. For applications where audible noise is a

concern, typical values of t

OFF

are chosen to be in the range of

15 ms to 35 ms.

(E) Stepper Motor Applications.

The MODE terminal can be used to optimize the performance

of the device in microstepping/sinusoidal stepper-motor drive

applications. When the load current is increasing, slow decay

mode is used to limit the switching losses in the device and iron

losses in the motor. This also improves the maximum rate at

which the load current can increase (as compared to fast de-

cay) due to the slow rate of decay during t

OFF

When the load current is decreasing, fast-decay mode is used

to regulate the load current to the desired level. This prevents

tailing of the current profile caused by the back-EMF voltage of

the stepper motor.

A2918SW

2-Phase Stepper Motor Bipolar Driver IC

A2918SW

Allegro MicroSystems product

■

Features

●

Fixed off-time PWM current control

●

Low saturation voltage (Sink transistor)

●

Internal thermal shutdown circuitry

●

Internal crossover-current protection cir-

cuitry

●

Internal UVLO protection

●

Internal transient-suppression diodes

●

Low thermal resistance 18-pin SIP

■

Absolute Maximum Ratings

Parameter

Symbol

Conditions

Ratings

Units

Motor supply voltage

Output current (peak)

O (peak)

≤

1.75

Output current (continuous)

1.5

Logic supply voltage

7.0

Logic input voltage range

−

0.3 to +7.0

Output emitter voltage

1.5

Package power dissipation

(Note1)

4.0

Operating temperature

−

20 to +85

Junction temperature

(Note2)

+150

Storage temperature

stg

−

55 to +150

●

Output current rating may be limited by duty cycle, ambient temperature, and heat sinking. Under any
set of conditions, do not exceed the specified current rating or a junction temperature of 150

Note 1: When ambient temperature is 25

C or over, derate using

−

32.0mW/

Note 2: Fault conditions where junction temperature (T

) exceeds 150

C will activate the device’s thermal

shutdown circuitry. These conditions can be tolerated but should be avoided.

■

Electrical Characteristics

Parameter

Symbol

Conditions

Limits

Units

min

typ

max

Power outputs (OUT

or OUT

)

Motor supply voltage range

Output leakage current

CEX

=0V

−

Output saturation voltage

CE (SUS)

1.5A, L=3.5mH

Sink driver, I

=+1.0A

0.8

Output sustaining voltage

CE (SAT)

Sink driver, I

=+1.5A

1.1

Source driver, I

−

1.0A

2.0

Source driver, I

−

1.5A

2.2

Clamp diode leakage current

=45V

Clamp diode forward voltage

=1.5A

2.0

Motor supply current

BB (ON)

Both bridges ON, no load

BB (OFF)

Both bridges OFF

Control logic

Input voltage

All inputs

2.4

All inputs

0.8

Input current

=2.4V

=0.8V

−

200

Reference voltage range

REF

Operating

1.5

Current control threshold

REF

SENSE

REF

=5V

9.5

10.5

Thermal shutdown temperature

170

Logic supply current

=0.8V, no load

140

●

“typ” values are for reference.

(Unless specified otherwise, T

=25

C, V

=45V, V

=4.75V to 5.25V, V

REF

=5V)

■

Terminal Connection Diagram

OUT

LOAD SUPPLY

SENSE

PHASE

REFERENCE

REF

PWM1

TSD

GROUND

LOGIC SUPPLY

ENABLE

PWM2

■

Derating

−

100

Ambient temperature Ta (C

)

Allowable package power dissipation P

(W)

31.25C

/ W

2-Phase/1-2 Phase Excitation

A2918SW

2-Phase Stepper Motor Bipolar Driver IC (2-Phase/1-2 Phase Excitation)

A2918SW

■

Truth Table

■

Internal Block Diagram

■

External Dimensions

Plastic SIP

ENABLE

PHASE

OUT

X=Don't Care Z=High impedance

3()

6.7

0.5

1 2 3

31.3

0.2

0.1

0.65

0.2

0.1

0.2

24.4

0.2

16.4

0.2

3.2

0.15

0.7

0.55

0.2

0.1

9.7

1 0.5

2.45

0.2

1.7

4.8

0.2

0.1

R-End

9.9

0.2

---

28.56

P1.68

0.7

3.2

0.15

3.8

---

+ ---

31.3

0.2

0.65

0.2

0.1

---

0.2

0.1

---

28.56

P1.68

0.4

1 2 3

2.2

0.1

1.6

0.6

4.6

0.6

3.0

0.6

7.5

0.6

6.0

0.6

0.55

0.2 0.1

+ ---

0.2

24.4

0.2

16.4

0.2

3.2

0.15

2.45

0.2

1.7

4.8

0.2

0.1

9.9

0.2

3.2

0.15

3.8

A2918SWV

A2918SWH

(Unit: mm)

SOURCE
DISABLE

LOGIC

SUPPLY

LOAD

SUPPLY

OUT

TSD

PWM2

PWM1

PHASE

ENABLE

SENSE

REFERENCE

GROUND

REF

PHASE

ENABLE

ONE SHOT

SOURCE
DISABLE

ONE SHOT

−

ICs per stick

A3952SB/SLB/SW

2-Phase Stepper Motor Bipolar Driver ICs

A3952SB/SLB/SW

■

Features

●

Fixed off-time PWM current control

●

Switching between power supply regenera-

tion mode and loop regeneration mode in

order to improve motor current response in

microstepping

●

External filter for sense terminal not required

●

Sleep (low current consumption) mode

●

Brake operation with PWM current limiting

●

Internal thermal shutdown circuitry

●

Internal crossover-current protection circuitry

●

Internal UVLO protection

●

Internal transient-suppression diodes

●

Low thermal resistance package

■

Electrical Characteristics

■

Absolute Maximum Ratings

Parameter

Symbol

Conditions

Ratings

Units

A3952SB A3952SLB A3952SW

Load supply voltage

Output current (peak)

O (Peak)

≤

3.5

Output current (continuous)

2.0

Logic supply voltage

7.0

Logic input voltage

−

0.3 to V

+0.3

Sense voltage

SENSE

1.5

Reference voltage

REF

Package power dissipation

(Note1)

2.90

1.86

3.47

Operating temperature

−

20 to +85

Junction temperature

(Note2)

+150

Storage temperature

stg

−

55 to +150

●

Output current rating may be limited by duty cycle, ambient temperature, and heat sinking. Under any
set of conditions, do not exceed the specified current rating or a junction temperature of 150

Note 1: When ambient temperature is 25

C or over, derate using

−

23.26mW/

C(SB),

−

14.93mW/

C(SLB)

−

27.78mW/

C(SW).

Note 2: Fault conditions where junction temperature (T

) exceeds 150

C will activate the device’s thermal

shutdown circuitry. These conditions can be tolerated but should be avoided.

(Unless specified otherwise, T

=25

C, V

=50V, VC

=5.0V, V

BRAKE

=2.0V, V

SENSE

= 0V, 20k

Ω

& 1000pF RC to ground)

Parameter

Symbol

Conditions

Limits

Units

min

typ

max

Power outputs

Load supply voltage range

Operating, I

2.0A, L=3mH

Output leakage current

CEX

<1.0

=0V

−

1.0

−

Source driver, I

−

0.5A

0.9

1.2

Source driver, I

−

1.0A

1.0

1.4

Output saturation voltage

CE (SAT)

Source driver, I

−

2.0A

1.2

1.8

Sink driver, I

=+0.5A

0.9

1.2

Sink driver, I

=+1.0A

1.0

1.4

Sink driver, I

=+2.0A

1.3

1.8

Clamp diode forward voltage

=0.5A

1.0

1.4

(Source or sink)

=1.0A

1.1

1.6

=2.0A

1.4

2.0

BB (ON)

ENABLE

=0.8V, V

BRAKE

=2.0V

2.9

6.0

Load supply current

BB (OFF)

ENABLE

=2.0V, V

MODE

=0.8V, V

BRAKE

=2.0V

3.1

6.5

(No load)

BB (BRAKE)

BRAKE

=2.0V

3.1

6.5

BB (SLEEP)

ENABLE

MODE

BRAKE

=2.0V

<1.0

Control logic

Logic supply voltage range

Operating

4.5

5.0

5.5

Logic input voltage

2.0

0.8

Logic input current

=2.0V

<1.0

=0.8V

−

2.0

−

200

Reference voltage range

REF

Operating

Reference input current

REF

=2.0V

Reference voltage divider ratio

REF

=15V

9.5

10.0

10.5

Comparator input offset voltage

REF

=0V

1.0

PWM RC fixed off-time

off

=1000pF, R

=20k

Ω

PWM minimum on-time

on (min)

=820pF, R

≥

12k

Ω

1.7

3.0

=1200pF, R

≥

12k

Ω

2.5

3.8

OUT

2.0A, 50% E

to 90% E

out

Transition:

ENABLE ON to SOURCE ON

2.9

ENABLE OFF to SOURCE OFF

0.7

ENABLE ON to SINK ON

2.4

Propagation delay time

ENABLE OFF to SINK OFF

0.7

PHASE CHANGE to SOURCE ON

2.9

PHASE CHANGE to SOURCE OFF

0.7

PHASE CHANGE to SINK ON

2.4

PHASE CHANGE to SINK OFF

0.7

pd (PWM)

Comparator Trip to SINK OFF

0.8

1.5

Thermal shutdown temperature

165

Thermal shutdown hysteresis

∆

UVLO enable threshold

CC (UVLO)

3.15

3.50

3.85

UVLO hysteresis

∆

CC (UVLO)

300

400

500

CC (ON)

ENABLE

=0.8V, V

BRAKE

=2.0V

Logic supply current

CC (OFF)

ENABLE

=2.0V, V

MODE

=0.8V, V

BRAKE

=2.0V

(No load)

CC (BRAKE)

BRAKE

=0.8V

CC (SLEEP)

ENABLE

MODE

BRAKE

=2.0V

3.0

5.0

●

“typ” values are for reference.

Allegro MicroSystems product

2-Phase/1-2 Phase Excitation

A3952SB/SLB/SW

2-Phase Stepper Motor Bipolar Driver ICs (2-Phase/1-2 Phase Excitation)

A3952SB/SLB/SW

■

Derating

■

Internal Block Diagram

■

Truth Table

■

External Dimensions

(Unit: mm)

■

Terminal Connection Diagram

Plastic DIP
(300mil)

Wide body plastic SOP
(300mil)

Plastic power SIP

ENABLE

BRAKE

PHASE

MODE

Operating Mode

OUT

Sleep mode

Standby

(Note 1)

Forward, fast current-decay mode

Forward, slow current-decay mode

Reverse, fast current-decay mode

Reverse, slow current-decay mode

Brake, fast current-decay mode

Brake, no current control

(Note 2)

BRAKE

PHASE

LOGIC

MODE

LOAD
SUPPLY

OUT

GROUND

SENSE

OUT

LOAD
SUPPLY

REF

GROUND

LOGIC

SUPPLY

ENABLE

BRAKE

PHASE

LOGIC

MODE

LOAD
SUPPLY

OUT

GROUND

SENSE

OUT

LOAD
SUPPLY

REF

GROUND

LOGIC

SUPPLY

ENABLE

PHASE

MODE

BRAKE

REF

LOAD

SUPPLY

LOGIC

SUPPLY

OUT

SENSE

ENABLE

LOGIC

GROUND

OUT

−

100

A3952SW 36

C/W

A3952SB 43

A3952S

LB 67

C/ W

Ambient temperatureTa (

Allowable package power dissipation P

(W)

1.27
0.40

0.32
0.23

10.65
10.00

7.60
7.40

10.50
10.10

0.51
0.33

2.65
2.35

SEATING PLANE

0.10 MIN.

1.27
BSC

TO 8

MODE

PHASE

ENABLE

BRAKE

LOGIC
SUPPLY

REF

GROUND

1.5V

BLANKING

PWM LATCH

−

SENSE

"B", "LB" , & "W"
PACKAGES

EMITTERS
"EB" ONLY

OUT

LOAD

SUPPLY

OUT

SLEEP &
STANDBY MODES

UVLO
& TSD

INPUT LOGIC

1.77

1.15

21.33
18.93

0.558
0.356

4.06
2.93

7.11
6.10

INDEX AREA

0.127MIN

7.62BSC

2.54BSC

5.33MAX

SEATING PLANE

0.39MIN

0.381
0.204

●

Thickness of lead is measured below seating plane.

●

Allowable variation in distance between leads is not cumulative.

Lead width of pin 1, 8, 9, 16 may be half the value shown here.
Maximum thickness of lead is 0.508mm.

Note 1:

ICs per stick

A3952SB

A3952SLB

A3952SW

A3952SB

A3952SLB

A3952SW

Don't Care

High impedance

Includes active pull-offs for power outputs

Includes internal default
V

SENSE

level for overcurrent protection

X :

Z :

Note 1:

Note 2:

●

Thickness of lead is measured below seating plane.

●

Allowable variation in distance between leads is not cumulative.

●

Lead is measured 0.762mm below seating plane.

4.57MAX

1.40
1.14

3.43
2.54

2.03
1.78

0.59
0.46

0.76
0.51

19.69
19.43

32.00
31.50

1.65
0.89

3.94
3.68

6.22
5.71

14.48
13.72

3.56

9.27

7.37MIN

SEATING
PLANE

2.54

0.25

INDEX
AREA

0.51

A3952SB/SLB/SW

2-Phase Stepper Motor Bipolar Driver ICs (2-Phase/1-2 Phase Excitation)

A3952SB/SLB/SW

■

Outline

Designed for bidirectional pulse-width modulated current con-

trol of inductive loads, the A3952S- is capable of continuous

output currents to

2A and operating voltages to 50V. Internal

fixed off-time PWM current-control circuitry can be used to regu-

late the maximum load current to a desired value. The peak

load current limit is set by the user’s selection of an input refer-

ence voltage and external sensing resistor. The fixed OFF-time

pulse duration is set by a user-selected external RC timing net-

work. Internal circuit protection includes thermal shutdown with

hysteresis, transient suppression diodes, and crossover-current

protection. Special power-up sequencing is not required.

With the ENABLE input held low, the PHASE input controls load

current polarity by selecting the appropriate source and sink

driver pair. The MODE input determines whether the PWM cur-

rent-control circuitry operates in a slow current-decay mode (only

the selected sink driver switching) or in a fast current-decay

mode (selected source and sink switching). A user-selectable

blanking window prevents false triggering of the PWM current

control circuitry. With the ENABLE input held high, all output

drivers are disabled. A sleep mode is provided to reduce power

consumption when inactive.

When a logic low is applied to the BRAKE input, the braking

function is enabled. This overrides ENABLE and PHASE to turn

OFF both source drivers and turn ON both sink drivers. The

brake function can be safely used to dynamically brake brush

dc motors.

■

FUNCTIONAL DESCRIPTION

(A) INTERNAL PWM CURRENT CONTROL DURING FOR-

WARD AND REVERSE OPERATION

The A3952S- contains a fixed OFF-time pulse-width modulated

(PWM) current-control circuit that can be used to limit the load

current to a desired value. The value of the current limiting (I

TRIP

)

is set by the selection of an external current sensing resistor

) and reference input voltage (V

REF

). The internal circuitry

compares the voltage across the external sense resistor to one

tenth the voltage on the REF input terminal, resulting in a func-

tion approximated by

In forward or reverse mode the current-control circuitry limits

the load current. When the load current reaches I

TRIP

, the com-

parator resets a latch to turn OFF the selected sink driver (in the

slow-decay mode) or selected sink and source driver pair (in

the fast-decay mode). In slow-decay mode, the selected sink

driver is disabled; the load inductance causes the current to

recirculate through the source driver and flyback diode (see fig-

ure 1). In fast-decay mode, the selected sink and source driver

pair are disabled; the load inductance causes the current to flow

from ground to the load supply via the ground clamp and flyback

diodes.

Fig. 1 Load-Current Paths

DRIVE CURRENT

RECIRCULATION (SLOW-DECAY MODE)

RECIRCULATION (FAST-DECAY MODE)

Fig. 2 Fast and Slow Current-Decay Waveforms

ENABLE

MODE

LOAD

CURRENT

TRIP

•

REF

Application Notes

The user selects an external resistor (R

) and capacitor (C

) to

determine the time period (t

off

) during which the drivers

remain disabled (see “RC Fixed OFF Time” below). At the end

of the R

interval, the drivers are re-enabled allowing the load

current to increase again. The PWM cycle repeats, maintaining

the load current at the desired value (see figure 2).

(B)INTERNAL PWM CURRENT CONTROL DURING BRAKE

MODE OPERATION

The brake circuit turns OFF both source drivers and turns ON

both sink drivers. For dc motor applications, this has the effect

of shorting the motor’s back-EMF voltage, resulting in current

flow that brakes the motor dynamically. However, if the back-

EMF voltage is large, and there is no PWM current limiting, then

the load current can increase to a value that approaches a locked

rotor condition. To limit the current, when the I

TRIP

level is reached,

the PWM circuit disables the conducting sink driver. The energy

stored in the motor’s inductance is then discharged into the load

supply causing the motor current to decay.

As in the case of forward/reverse operation, the drivers are re-

enabled after a time given by t

off

•

(see”RC Fixed OFF Time”

below). Depending on the back-EMF voltage (proportional to

the motor’s decreasing speed), the load current again may in-

crease to I

TRIP

. If so, the PWM cycle will repeat, limiting the load

current to the desired value.

(1) Brake Operation-MODE Input High

During braking, when the MODE input is high, the current limit

can be approximated by

A3952SB/SLB/SW

2-Phase Stepper Motor Bipolar Driver ICs (2-Phase/1-2 Phase Excitation)

A3952SB/SLB/SW

TRIP

•

REF

TRIP

1.5V

OFF

•

CAUTION: Because the kinetic energy stored in the motor and

load inertia is being converted into current, which charges the

supply bulk capacitance (power supply output and

decoupling capacitance), care must be taken to ensure the ca-

pacitance is sufficient to absorb the energy without exceed-

ing the voltage rating of any devices connected to the motor

supply.

(2) Brake Operation-MODE Input Low

During braking,with the MODE input low, the peak current limit

defaults internally to a value approximated by

In this mode, the value of R

determines the I

TRIP

value indepen-

dent of V

REF

. This is useful in applicaions with differing run and

brake currents and no practical method of varying V

REF

Choosing a small value for R

essentially disables the current

limiting during braking. Therefore, care should be taken to en-

sure that the motor’s current does not exceed the absolute

maximum ratings of the device. The braking current can be

measured by using an oscilloscope with a current probe con-

nected to one of the motor’s leads.

(C) RC Fixed OFF Time

The internal PWM current control circuitry uses a one shot to

control the time the driver (s) remain (s) OFF. The one shot

time, t

off

(fixed OFF time), is determined by the selection of an

external resistor (R

) and capacitor (C

) connected in parallel

from the RC terminal to ground. The fixed OFF time, over a

range of values of C

=820pF to 1500pF and R

=12k

Ω

to 100k

Ω

is approximated by

When the PWM latch is reset by the current comparator, the

voltage on the RC terminal will begin to decay from approxi-

mately 3 volts. When the voltage on the RC terminal reaches

approximately 1.1 volt, the PWM latch is set, thereby re-enabling

the driver (s).

(D) RC Blanking

In addition to determining the fixed OFF-time of the PWM con-

trol circuit, the C

component sets the comparator blanking time.

This function blanks the output of the comparator when the out-

puts are switched by the internal current control circuitry (or by

the PHASE, BRAKE, or ENABLE inputs). The comparator out-

put is blanked to prevent false over-current detections due to

reverse recovery currents of the clamp diodes, and/or switching

transients related to distributed capacitance in the load.

During internal PWM operation, at the end of the t

off

time, the

comparator’s output is blanked and C

begins to be charged

from approximately 1.1V by an internal current source of ap-

proximately 1mA. The comparator output remains blanked until

the voltage on C

reaches approximately 3.0 volts.

Similarly, when a transition of the PHASE input occurs, C

discharged to near ground during the crossover delay time (the

crossover delay time is present to prevent simultaneous con-

duction of the source and sink drivers). After the crossover de-

lay, C

is charged by an internal current source of approximately

1mA. The comparator output remains blanked until the voltage

on C

reaches approximately 3.0 volts.

Similarly, when the device is disabled via the ENABLE input, C

is discharged to near ground. When the device is re-enabled,

is charged by the internal current source. The comparator

output remains blanked until the voltage on C

reaches approxi-

mately 3.0V.

For applications that use the internal fast-decay mode PWM

operation, the minimum recommended value is C

=1200pF

5%.

For all other applications, the minimum recommended value is

=820pF

5%. These values ensure that the blanking time is

sufficient to avoid false trips of the comparator under normal

operating conditions. For optimal regulation of the load current,

the above values for C

are recommended and the value of R

can be sized to determine t

off

. For more information regarding

load current regulation, see below.

(E) LOAD CURRENT REGULATION WITH THE INTERNAL

PWM CURRENT-CONTROL CIRCUITRY

When the device is operating in slow-decay mode, there is a

limit to the lowest level that the PWM current-control circuitry

can regulate load current. The limitation is the minimum duty

cycle, which is a function of the user-selected value of t

off

and

the maxuimum value of the minimum ON-time pulse, t

on (min)

, that

occurs each time the PWM latch is reset. If the motor is not

rotating, as in the case of a stepper motor in hold/detent mode,

or a brush dc motor when stalled or at startup, the worst-case

value of current regulation can be approximated by

where t

off

•

, R

LOAD

is the series resistance of the load, V

the load/motor supply voltage, and t

on (min)

max is specified in the

electrical characteristics table. When the motor is rotating, the

back EMF generated will influence the above relationship. For

brush dc motor applications, the current regulation is improved.

For stepper motor applications when the motor is rotating, the

effect is more complex. A discussion of this subject is included

in the section on stepper motors under “Applications”.

The following procedure can be used to evaluate the worst-case

slow-decay internal PWM load current regulation in the system:

Set V

REF

to 0 volts. With the load connected and the PWM current

control operating in slow-decay mode, use an oscilloscope to

measure the time the output is low (sink ON) for the output that is

chopping. This is the typical minimum ON time (t

on (min)

typ) for the

1.05

•

on (min)

max + t

off

)

•

LOAD

[(V

−

SAT (source

sink)

)

•

on (min)

max]

−

[1.05

•

SAT (sink)

+ V

)

•

off

]

(AV)

≅

A3952SB/SLB/SW

2-Phase Stepper Motor Bipolar Driver ICs (2-Phase/1-2 Phase Excitation)

A3952SB/SLB/SW

100 k

Ω

20 k

Ω

1N4001

2N2222

Fig. 3 Synchronous Fixed-Frequency Control Circuit

device. C

then should be increased until the measured value

of t

on (min)

is equal to t

on (min)

max)=3.0

s as specified in the electri-

cal characteristics table. When the new value of C

has been

set, the value of R

should be decreased so the value for

off

•

(with the artificially increased value of C

) is equal to

105% of the nominal design value. The worst-case load current

regulation then can be measured in the system under operating

conditions.

In applications utilizing both fast-and slow-decay internal PWM

modes, the performance of the slow-decay current regulation

should be evaluated per the above procedure and a t

on (min)

max

of 3.8

s. This corresponds to a C

value of 1200pF, which is

required to ensure sufficient blanking during fast-decay internal

PWM.

(F) LOAD CURRENT REGULATION WITH EXTERNAL PWM

OF THE PHASE AND ENABLE INPUTS

The PHASE and ENABLE inputs can be pulse-width modulated

to regulate load current. Typical propagation delays from the

PHASE and ENABLE inputs to transitions of the power outputs

are specified in the electrical characteristics table. If the internal

PWM current control is used, then the comparator blanking func-

tion is active during phase and enable transitions. This elimi-

nates false tripping of the over-current comparator caused by

switching transients (see “RC Blanking” above).

(1) ENABLE Pulse-Width Modulation

With the MODE input low, toggling the ENABLE input turns ON

and OFF the selected source and sink drivers. The correspond-

ing pair of flyback and ground clamp diodes conduct after the

drivers are disabled, resulting in fast current decay. When the

device is enabled, the internal current control circuitry will be

active and can be used to limit the load current in a slow-decay

mode.

For applications that PWM the ENABLE input, and desire that

the internal current limiting circuit function in the fast-decay mode,

the ENABLE input signal should be inverted and connected to

the MODE input. This prevents the device from being switched

into sleep mode when the ENABLE input is low.

(2) PHASE Pulse-Width Modulation

Toggling the PHASE terminal determines/controls which sink/

source pair is enabled, producing a load current that varies with

the duty cycle and remains continuous at all times. This can

have added benefits in bidrectional brush dc servo motor appli-

cations as the transfer function between the duty cycle on the

phase input and the average voltage applied to the motor is

more linear than in the case of ENABLE PWM control (which

produces a discontinuous current at low current levels). See

also, “DC Motor Applications” below.

(3) SYNCHRONOUS FIXED-FREQUENCY PWM

The internal PWM current-control circuitry of multiple A3952S-

devices can be synchronized by using the simple circuit shown

in figure 3. A555IC can be used to generate the reset pulse/

blanking signal (t

) and the period of the PWM cycle (t

). The

value of t

should be a minimum of 1.5

s in slow-decay mode

and 2

s in fast-decay mode. When used in this configuration,

the R

and C

components should be omitted. The PHASE and

ENABLE inputs should not be PWMed with this circuit configu-

ration due to the absence of a blanking function synchronous

with their transitions.

(G)MISCELLANEOUS INFORMATION

A logic high applied to both the ENABLE and MODE terminals

puts the device into a sleep mode to minimize current consump-

tion when not in use.

An internally generated dead time prevents crossover currents

that can occur when switching phase or braking.

Thermal protection circuitry turns OFF all drivers should the junc-

tion temperature reach 165

C (typical). This is intended only to

protect the device from failures due to excessive junction tem-

peratures and should not imply that output short circuits are

permitted. The hysteresis of the thermal shutdown circuit is ap-

proximately 15

If the internal current-control circuitry is not used; the V

REF

ter-

minal should be connected to V

, the SENSE terminal should

be connected to ground, and the RC terminal should be left

floating (no connection).

An internal under-voltage lockout circuit prevents simultaneous

conduction of the outputs when the device is powered up or

powered down.

A3952SB/SLB/SW

2-Phase Stepper Motor Bipolar Driver ICs (2-Phase/1-2 Phase Excitation)

A3952SB/SLB/SW

OUTP

LOAD

−

[(I

TRIP

•

LOAD

)+V

BEMF

])

•

pd (pwm)

TRIP

(0.375 to 1.125)

+ (2V

OUT

)

■

APPLICATION NOTES

(A) Current Sensing

The actual peak load current (I

OUTP

) will be greater than the cal-

culated value of I

TRIP

due to delays in the turn OFF of the driv-

ers. The amount of overshoot can be approximated as

where V

is the load/motor supply voltage, V

BEMF

is the back-

EMF voltage of the load, R

LOAD

and L

LOAD

are the resistance and

inductance of the load respectively, and t

pd (pwm)

is the propaga-

tion delay as specified in the electrical characteristics table.

The reference terminal has an equivalent input resistance of

50k

Ω±

30%. This should be taken into account when determin-

ing the impedance of the external circuit that sets the reference

voltage value.

To minimize current-sensing inaccuracies caused by ground

trace IR drops, the current-sensing resistor should have a sepa-

rate return to the ground terminal of the device. For low-value

sense resistors, the IR drops in the PCB can be significant and

should be taken into account. The use of sockets should be

avoided as their contact resistance can cause variations in the

effective value of R

Larger values of R

reduce the aforementioned effects but can

result in excessive heating and power loss in the sense resistor.

The selected value of R

must not cause the SENSE terminal

absolute maximum voltage rating to be exceeded. The recom-

mended value of R

is in the range of

The current-sensing comparator functions down to ground al-

lowing the device to be used in microstepping, sinusoidal, and

other varying current profile applications.

(B) Thermal Considerations

For reliable operation, it is recommended that the maximum

junction temperature be kept as low as possible, typically 90

to 125

C. The junction temperature can be measured by at-

taching a thermocouple to the power tab/batwing of the device

and measuring the tab temperature, T

. The junction tempera-

ture can then be approximated by using the formula

where V

is the clamp diode forward voltage and can be deter-

mined from the electrical specification table for the given level

of I

OUT

. The value for R

is given in the package thermal resis-

tance table for the appropriate package.

The power dissipation of the batwing packages can be improved

by 20 to 30% by adding a section of printed circuit board copper

(typically 6 to 18 square centimeters) connected to the batwing

terminals of the device.

The thermal performance in applications with high load currents

and/or high duty cycles can be improved by adding external

diodes in parallel with the internal diodes. In internal PWM slow-

decay applications, only the tow top-side (flyback) diodes need

be added. For internal fast-decay PWM, or external PHASE or

ENABLE input PWM applications, all four external diodes should

be added for maximum junction temperature reduction.

(C)PCB Layout

The load supply terminal, V

, should be decoupled (>47

F elec-

trolytic and 0.1

F ceramic capacitors are recommended) as

close to the device as is physically practical. To minimize the

effect of system ground I

•

R drops on the logic and reference

input signals, the system ground should have a low-resistance

return to the load supply voltage.

See also “Current Sensing” and “Thermal Considerations” above.

(D)Fixed Off-Time Selection

With increasing values of t

off

, switching losses decrease, low-

level load-current regulation improves, EMI is reduced, the PWM

frequency will decrease, and ripple current will increase. The

value of t

off

can be chosen for optimization of these parameters.

For applications where audible noise is a concern, typical val-

ues of t

off

are chosen to be in the range of 15 to 35

(E) Stepper Motor Applications

The MODE terminal can be used to optimize the performance

of the device in microstepping/sinusoidal stepper motor drive

applications. When the average load current is increasing, slow-

decay mode is used to limit the switching losses in the device

and iron losses in the motor.

This also improves the maximum rate at which the load current

can increase (as compared to fast decay) due to the slow rate

of decay during t

off

. When the average load current is decreas-

ing, fast-decay mode is used to regulate the load current to the

desired level. This prevents tailing of the current profile caused

by the back-EMF voltage of the stepper motor.

In stepper motor applications applying a constant current to the

load, slow-decay mode PWM is used typically to limit the switch-

ing losses in the device and iron losses in the motor.

A3952SB/SLB/SW

2-Phase Stepper Motor Bipolar Driver ICs (2-Phase/1-2 Phase Excitation)

A3952SB/SLB/SW

LOAD

BEMF

+ V

)

LOAD

REF

(10

•

)

•

(Chopping off-time setting)

12k~100k

Ω

820~1500pF (When using slow current-decay mode only)
1200~1500pF (When using fast current-decay mode only)

off

≅

T =

PHASE

MODE

REF1

REF2

ENABLE

LOGIC

0.5

Ω

17k

Ω/

25k

Ω

17k

Ω/

Ω

820pF/1200pF

0.5

Ω

+5V

47 F

820pF/1200pF

Fig. 4 Example of stepper motor drive

(F) Application circuit (Bipolar stepper motor drive)

(G)DC Motor Applications

In closed-loop systems, the speed of a dc motor can be con-

trolled by PWM of the PHASE or ENABLE inputs, or by varying

the REF input voltage (V

REF

). In digital systems (microproces-

sor controlled), PWM of the PHASE or ENABLE input is used

typically thus avoiding the need to generate a variable analog

voltage reference. In this case, a dc voltage on the REF input is

used typically to limit the maximum load current.

In dc servo applications that require accurate positioning at low

or zero speed, PWM of the PHASE input is selected typically.

This simplifies the servo-control loop because the transfer func-

tion between the duty cycle on the PHASE input and the aver-

age voltage applied to the motor is more linear than in the case

of ENABLE PWM control (which produces a discontinuous cur-

rent at low-current levels).

With bidirectional dc servo motors, the PHASE terminal can be

used for mechanical direction control. Similar to when braking

the motor dynamically, abrupt changes in the direction of a ro-

tating motor produce a currrent generated by the back EMF.

The current generated will depend on the mode of operation. If

the internal current-control circuitry is not being used, then the

maximum load current generated can be approximated by

where V

BEMF

is proportional to the motor’s speed. If the internal

slow-decay current-control circuitry is used, then the maximum

load current generated can be approximated by I

LOAD

BEMF

LOAD

. For both cases, care must be taken to ensure the maxi-

mum ratings of the device are not exceeded. If the internal fast-

decay current-control circuitry is used, then the load current will

regulate to a value given by

CAUTION: In fast-decay mode, when the direction of the motor

is changed abruptly, the kinetic energy stored in the motor and

load inertia will be converted into current that charges the V

supply bulk capacitance (power supply output and decoupling

capacitance). Care must be taken to ensure the capacitance is

sufficient to absorb the energy without exceeding the voltage

rating of any devices connected to the motor supply.

See also, the sections on brake operation under “Functional

Description,” above.

UDN2916B/LB

2-Phase Stepper Motor Bipolar Driver ICs

UDN2916B/LB

Allegro MicroSystems product

■

Features

●

Fixed off-time PWM current control

●

Internal 1/3 and 2/3 reference divider

●

1-phase/2-phase/W1-2 phase excitation

mode with digital input

●

Microstepping with reference input

●

Low saturation voltage (Sink transistor)

●

Internal thermal shutdown circuitry

●

Internal crossover-current protection cir-

cuitry

●

Internal UVLO protection

●

Internal transient-suppression diodes

●

Low thermal resistance package

■

Absolute Maximum Ratings

Parameter

Symbol

Conditions

Ratings

Units

UDN2916B

UDN2916LB

Motor supply voltage

Output current (peak)

O (peak)

≤

1.0

Output current (continuous)

0.75

Logic supply voltage

7.0

Logic input voltage range

−

0.3 to +7.0

Output emitter voltage

1.5

Package power dissipation

(Note1)

3.12

2.27

Operating temperature

−

20 to +85

Junction temperature

(Note2)

+150

Storage temperature

stg

−

55 to +150

●

Output current rating may be limited by duty cycle, ambient temperature, and heat sinking. Under any
set of conditions, do not exceed the specified current rating or a junction temperature of 150

Note 1: When ambient temperature is 25

C or over, derate using

−

25mW/

C (UDN2916B) or

−

18.2mW/

C (UDN2916LB).

Note 2: Fault conditions where junction temperature (T

) exceeds 150

C will activate the device’s thermal

shutdown circuitry. These conditions can be tolerated but should be avoided.

■

Electrical Characteristics

Parameter

Symbol

Conditions

Limits

Units

min

typ

max

Power outputs (OUT

or OUT

)

Motor supply voltage range

Output leakage current

CEX

Sink driver, V

<1.0

Source driver, V

=0V

−

1.0

−

Output sustaining voltage

CE (SUS)

750mA, L=3.0mH

Sink driver, I

=+500mA

0.4

0.6

Output saturation voltage

CE (SAT)

Sink driver, I

=+750mA

1.0

1.2

Source driver, I

−

500mA

1.0

1.2

Source driver, I

−

750mA

1.3

1.5

Clamp diode leakage current

=45V

<1.0

Clamp diode forward voltage

=750mA

1.6

2.0

Motor supply current

BB (ON)

Both bridges ON, no load

BB (OFF)

Both bridges OFF

5.0

Control logic

Input voltage

All inputs

2.4

All inputs

0.8

Input current

=2.4V

<1.0

=0.8V

−

3.0

−

200

Reference voltage range

REF

Operating

1.5

7.5

=0.8V

9.5

10.0

10.5

Current control threshold

REF

SENSE

=2.4V, I

=0.8V

13.5

15.0

16.5

=0.8V, I

=2.4V

25.5

30.0

34.5

Thermal shutdown temperature

170

Logic supply current

CC (ON)

=0.8V, no load

CC (OFF)

=2.4V, no load

●

“typ” values are for reference.

(Unless specified otherwise, T

=25

C, V

=45V, V

=4.75V to 5.25V, V

REF

=5.0V)

■

Terminal Connection Diagram

UDN2916B

OUT

LOAD SUPPLY

SENSE

OUT

PHASE

REF1

LOGIC SUPPLY

GROUND

OUT

PHASE

REF2

GROUND

PWM 2

PWM 1

SENSE

UDN2916LB

PHASE

REF 2

PHASE

REF1

GROUND

LOGIC SUPPLY

PWM 1

PWM 2

LOAD SUPPLY

OUT

GROUND

SENSE

2-Phase/1-2 Phase/W1-2 Phase Excitation

UDN2916B/LB

2-Phase Stepper Motor Bipolar Driver ICs (2-Phase/1-2 Phase/W1-2 Phase Excitation)

UDN2916B/LB

■

Internal Block Diagram

(1/2 Circuit)

■

Derating

■

Truth Table

■

External Dimensions

■

Application Circuit

(UDN2916LB)

Plastic DIP (300mil)

Wide body plastic SOP (300mil)

PHASE

OUT

Output Current

REF

/ (

TRIP

REF

/ (

TRIP

2/3

REF

/ (

TRIP

1/3

REF

SOURCE
DISABLE

SENSE

20 k

Ω

40 k

Ω

10 k

Ω

OUT

ONE
SHOT

−

UDN2916B

UDN2916LB

−

100

UDN2916B 40

UDN2916LB 55

C/ W

Ambient temperature Ta (

Allowable package power dissipation P

(W)

1.27
0.40

0.32
0.23

10.65
10.00

7.60
7.40

15.60
15.20

0.51
0.33

2.65
2.35

SEATING PLANE

0.10 MIN

1.27
BSC

TO 8

1.77

1.15

32.30
28.60

0.558
0.356

4.06
2.93

7.11
6.10

INDEX AREA

0.127MIN

7.62BSC

2.54BSC

5.33MAX

SEATING PLANE

0.39MIN

0.381
0.204

●

Thickness of lead is measured below seating plane.

●

Allowable variation in distance between leads is not cumulative.

PWM 1

PWM 2

From P

*2 V

REF

+5V

●

Off-time setting

off

≅

(Unit: mm)

: 1.5

Ω

, 1/2W (1.0 to 2.0

Ω

, 1 to 1/2W)

REF

: 5.0V (1.5 to 7.5V)

: 56k

Ω

(20k to 100k

Ω

)

: 470pF (100 to 1,000pF)

: 1k

Ω

: 4,700pF (470 to 10,000pF)

: 100 F

ICs per stick

●

Pin material: copper, pin surface treatment: solder plating

●

Package index may be *1.

●

Allowable variation in distance between leads is not cumulative.

●

Web (batwing) type lead frames are used for pin 6, 7, 18, 19.

The pins are connected to GND.

UDN2916B/LB

2-Phase Stepper Motor Bipolar Driver ICs (2-Phase/1-2 Phase/W1-2 Phase Excitation)

UDN2916B/LB

●

PWM CURRENT CONTROL

The UDN2916B/LB dual bridges are designed to drive both wind-

ings of a bipolar stepper motor. Output current is sensed and

controlled independently in each bridge by an external sense

resistor (R

), internal comparator, and monostable multivibrator.

When the bridge is turned ON, current increases in the motor

winding and it is sensed by the external sense resistor until the

sense voltage (V

SENSE

) reaches the level set at the comparator’s

input:

The comparator then triggers the monostable which turns OFF

the source driver of the bridge. The actual load current peak

will be slightly higher than the trip point (especially for low-in-

ductance loads) because of the internal logic and switching de-

lays. This delay (t

) is typically 2

s. After turn-off, the motor

current decays, circulating through the ground-clamp diode and

sink transistor. The source driver’s OFF time (and therefore the

magnitude of the current decrease) is determined by the

monostable’s external RC timing components, where t

off

wihtin the range of 20k

Ω

to 100k

Ω

and 100pF to 1000 pF.

When the source driver is re-enabled, the winding current (the

sense voltage) is again allowed to rise to the comparator ’s

threshold. This cycle repeats itself, maintaining the average

motor winding current at the desired level.

Loads with high distributed capacitances may result in high turn-

ON current peaks. This peak (appearing across R

) will attempt

to trip the comparator, resulting in erroneous current control or

high-frequency oscillations. An external R

time delay should

be used to further delay the action of the comparator. Depend-

ing on load type, many applications will not require these exter-

nal components (SENSE connected to E.)

PHASE

OUT

TRIP

off

−

TRIP

REF

/ 10R

SENSE

Load

BRIDGE ON

SOURCE OFF

ALL OFF

PWM OUTPUT CURRENT WAVE FORM

Load-Current Paths

Application Notes

●

LOGIC CONTROL OF OUTPUT CURRENT

Two logic level inptus (I

and I

) allow digital selection of the

motor winding current at 100%, 67%, 33%, or 0% of the maxi-

mum level per the table. The 0% output current condition turns

OFF all drivers in the bridge and can be used as an OUTPUT

ENABLE function.

These logic level inputs greatly enhance the implementation of

P-controlled drive formats.

During half-step operations, the I

and I

allow the

P to control

the motor at a constant torque between all positions in an eight-

step sequence. This is accomplished by digitally selecting 100%

drive current when only one phase is ON and 67% drive current

when two phases are ON. Logic highs on both I

and I

turn

OFF all drivers to allow rapid current decay when switching

phases. This helps to ensure proper motor operation at high

step rates.

The logic control inputs can also be used to select a reduced

current level (and reduced power dissipation) for ‘hold’ condi-

tions and/or increased current (and available torque) for start-

up conditions.

●

SWITCHING THE EXCITATION CURRENT DIRECTION

The PHASE input to each bridge determines the direction moter

winding current flows. An internally generated deadtime (ap-

proximately 2

s) prevents crossover currents that can occur

when switching the PHASE input.

UDN2916B/LB

2-Phase Stepper Motor Bipolar Driver ICs (2-Phase/1-2 Phase/W1-2 Phase Excitation)

UDN2916B/LB

●

REDUCTION AND DISPERSION OF POWER LOSS

The thermal performance can be improved by adding four ex-

ternal Schottky barrier diodes (AK03 or other) between each

output terminal and ground. In most applications, the chopping

ON time is shorter than the chopping OFF time (small ON duty).

Therefore, a great part of the power loss of the driver IC is at-

tributable to the motor regenerative current during the chopping

OFF period. The regenerative current from the motor flows

through the current sensing resistor and ground clamp diode

and returns to the motor. The voltage drop across this path

causes the power loss. On this path, the forward voltage VF of

ground clamp diode shows the greatest drop. This means that

adding Schottky barrier diodes will improve the thermal perfor-

mance if their V

characteristic is smaller than that of the inter-

nal ground clamp diode.

The external diodes also disperse the loss (a source of heat)

and reduce the package power dissipation P

of the driver IC.

Consequently, a greater output current can be obtained.

●

CONTROL SEQUENCE OF 1-2 OR W1-2 PHASE EXCITATION

To reduce vibration when the stepper motor is rotating, the

UDN2916B/LB can provide 1-2 or W1-2 phase excitation for

the control sequence without varying the V

REF

terminal voltage.

The step angle is

OUT

GND

Schottky barrier
diode

To motor

Note: When the sequence no. is 0, 4, 8, or 12, power-down can be set as follows

=1, I

=0: Sequence No. 0 or 8

=1, I

=0: Sequence No. 4 or 12

If power-down is necessary for a sequence other than 0, 4, 8, or 12, lower the V

REF

terminal voltage. However, do not set the voltage lower than the lower limit of the setting range.

(NABLE1= ENABLE 2= 0)

Phase A

Sequence

No.

Current ratio

Phase B

Current ratio

1/3

2/3

1/3

2/3

1/3

2/3

1/3

2/3

1/3

1-2 phase
excitation

W1-2 phase

excitation

Phase B

Phase A

(4)

(3)

(2)

(1)

(0)

Combined vector (1/4 cycle)

Control sequence (1-2/W1-2 phase)

1/2 step : 1-2 excitation

About 1/4 step : W1-2 excitation

The control sequence is as shown below. (This sequence uses

threshold signal terminals Io and I

for PWM current control.)

UDN2916B/LB

2-Phase Stepper Motor Bipolar Driver ICs (2-Phase/1-2 Phase/W1-2 Phase Excitation)

UDN2916B/LB

Note: The V

REF

terminal voltage cannot be set to 0 V. To make the output current ratio 0%, set I

=1.

When the sequence is 0, 8, 16, or 24, power-down can be set as follows:
I

=1, I

=0: Sequence No. 0 or 16

=1, I

=0: Sequence No. 8 or 24

Phase A

Sequence

No.

Current ratio (%)

REF1

(V)

Current ratio (%)

REF2

(V)

Phase B

7.5

100

1.5

7.4

1.5

6.9

2.9

6.2

4.2

5.3

4.2

6.2

2.9

6.9

1.5

7.4

1.5

7.5

100

1.5

7.4

2.9

6.9

4.2

6.2

5.3

6.2

4.2

6.9

2.9

7.4

1.5

7.5

100

1.5

7.4

1.5

6.9

2.9

6.2

4.2

5.3

4.2

6.2

2.9

6.9

1.5

7.4

1.5

7.5

100

1.5

7.4

2.9

6.9

4.2

6.2

5.3

6.2

4.2

6.9

2.9

7.4

1.5

●

REF

terminal

REF

is the reference voltage input terminal for PWM constant

current control. To realize stable ensure a stable signal, make

sure noise is not applied to the terminal.

●

terminal

To prevent voltage spikes on the load power supply terminal

), connect a large capacitor (

≥

F) between the V

termi-

nal and ground as close to the device as possible. Make sure

the load supply voltage does not exceed 45 V.

Control sequence (microstepping)

●

MICROSTEPPING (1/8 STEP) CONTROL SEQUENCE

Varying the V

REF

terminal voltage in steps provides 1/8

microstepping and reduces motor vibration greatly. The

microstepping control sequence is as follows:

●

Thermal protection

Thermal protection circuitry turns OFF all drivers when the junc-

tion temperature reaches +170

C. It is only intended to protect

the device from failures due to excessive junction temperature

and should not imply that output short circuits are permitted.

The output drivers are re-enabled when the junction tempera-

ture cools to +145

UDN2917EB

2-Phase Stepper Motor Bipolar Driver IC

UDN2917EB

Allegro MicroSystems product

■

Features

●

Fixed off-time PWM current control

●

Internal 1/3 and 2/3 reference divider

●

1-phase/2-phase/W1-2 phase excitation

mode with digital input

●

Microstepping with reference input

●

Low saturation voltage (Sink transistor)

●

Internal thermal shutdown circuitry

●

Internal crossover-current protection cir-

cuitry

●

Internal UVLO protection

●

Internal transient-suppression diodes

●

Low thermal resistance 44-pin PLCC

■

Absolute Maximum Ratings

Parameter

Symbol

Conditions

Ratings

Units

Motor supply voltage

Output current (peak)

O (peak)

≤

1.75

Output current (continuous)

1.5

Logic supply voltage

7.0

Logic input voltage range

−

0.3 to +7.0

Output emitter voltage

1.0

Package power dissipation

(Note1)

4.16

Operating temperature

−

20 to +85

Junction temperature

(Note2)

+150

Storage temperature

stg

−

55 to +150

●

Output current rating may be limited by duty cycle, ambient temperature, and heat sinking. Under any
set of conditions, do not exceed the specified current rating or a junction temperature of 150

Note 1: When ambient temperature is 25

C or over, derate using

−

33.3mW/

Note 2: Fault conditions where junction temperature (T

) exceeds 150

C will activate the device’s thermal

shutdown circuitry. These conditions can be tolerated but should be avoided.

■

Electrical Characteristics

Parameter

Symbol

Conditions

Limits

Units

min

typ

max

Power outputs (OUT

or OUT

)

Motor supply voltage range

Output leakage current

CEX

Sink driver, V

<1.0

Source driver, V

=0V

−

1.0

−

Output sustaining voltage

CE (SUS)

1.5A, L=3.5mH

Sink driver, I

=+1.0A

0.5

0.7

Output saturation voltage

CE (SAT)

Sink driver, I

=+1.5A

0.8

1.0

Source driver, I

−

1.0A

1.8

1.9

Source driver, I

−

1.5A

1.9

2.1

Clamp diode leakage current

=45V

<1.0

Clamp diode forward voltage

=1.5A

1.6

2.0

Motor supply current

BB (ON)

Both bridges ON, no load

9.0

BB (OFF)

Both bridges OFF

4.0

6.0

Control logic

Logic supply voltage

Operating

4.75

5.0

5.25

Input voltage

All inputs

2.4

All inputs

0.8

Input current

=2.4V

<1.0

=0.8V

−

3.0

−

200

Reference voltage range

REF

Operating

1.5

7.5

=0.8V

9.5

10.0

10.5

Current control threshold

REF

SENSE

=2.4V, I

=0.8V

13.5

15.0

16.5

=0.8V, I

=2.4V

25.5

30.0

34.5

Thermal shutdown temperature

170

Logic supply current

CC (ON)

=0.8V, no load

105

CC (OFF)

=2.4V, no load

●

“typ” values are for reference.

(Unless specified otherwise, T

=25

C, V

=45V, V

=5.0V, V

REF

=5.0V)

■

Terminal Connection Diagram

GROUND

OUT

REF1

SENSE

PHASE

LOGIC SUPPLY

ENABLE

OUT

REF2

SENSE

PHASE

LOAD SUPPLY

ENABLE

PWM 1

PWM 2

■

Derating

−

100

Ambient temperature Ta (

Allowable package power dissipation

(W)

2-Phase/1-2 Phase/W1-2 Phase Excitation

UDN2917EB

2-Phase Stepper Motor Bipolar Driver IC (2-Phase/1-2 Phase/W1-2 Phase Excitation)

UDN2917EB

■

Truth Table

■

External Dimensions

Plastic PLCC

■

Application Circuit

(Unit: mm)

PWM 1

PWM 2

STEPPER
MOTOR

ENABLE

Digital control signal

PHASE

ENABLE

PHASE

REF1

REF2

VBB

●

Off-time setting

off

≅

: 0.82

Ω

, 1W (0.5 to 1.0

Ω

, 2 to 1W)

REF

: 5.0V (1.5 to 7.5V)

: 56k

Ω

(20k to 100k

Ω

)

: 470pF (200 to 500pF)

: 1k

Ω

: 3,300pF (470 to 10,000pF)

VBB

: 100 F

0.51
MIN

4.57
4.19

0.533
0.331

16.66
16.51

17.65
17.40

1.27
BSC

INDEX AREA

0.812
0.661

ENABLE

PHASE

OUT

X=Don't Care Z=High impedance

Output Current

REF

(10

)=I

TRIP

REF

(15

)=I

TRIP

2/3

REF

(30

)=I

TRIP

1/3

●

Allowable variation in distance between leads is not cumulative.

Note 1: Web type leads are internally connected together.

ICs per stick

■

Internal Block Diagram

(1/2 Circuit)

REF

SOURCE
DISABLE

SENSE

20 k

Ω

40 k

Ω

10 k

Ω

OUT

ONE
SHOT

−

UDN2917EB

2-Phase Stepper Motor Bipolar Driver IC (2-Phase/1-2 Phase/W1-2 Phase Excitation)

UDN2917EB

Note: When the sequence no. is 0, 4, 8, or 12, power-down can be set as follows

=1, I

=0: Sequence No. 0 or 8

=1, I

=0: Sequence No. 4 or 12

If power-down is necessary for a sequence other than 0, 4, 8, or 12, lower the
V

REF

terminal voltage. However, do not set the voltage lower than the lower limit of the setting range.

(ENABLE1= ENABLE 2=0)

Phase A

Sequence

No.

Current ratio

Phase B

Current ratio

1/3

2/3

1/3

2/3

1/3

2/3

1/3

2/3

1/3

1-2 phase

excitation

W1-2 phase

excitation

Application Notes

●

REDUCTION AND DISPERSION OF POWER LOSS

The thermal performance can be improved by adding four ex-

ternal Schottky barrier diodes (EK13 or other) between each

output terminal and ground. In most applications, the chopping

ON time is shorter than the chopping OFF time (small ON duty).

Therefore, a great part of the power loss of the driver IC is at-

tributable to the motor regenerative current during the chopping

OFF period. The regenerative current from the motor flows

through the current sensing resistor and ground clamp diode

and returns to the motor. The voltage drop across this path

causes the power loss. On this path, the forward voltage V

ground clamp diode shows the greatest drop. This means that

adding Schottky barrier diodes will improve the thermal perfor-

mance if their V

characteristic is smaller than that of the inter-

nal ground clamp diode.

The external diodes also disperse the loss (a source of heat)

and reduce the package power dissipation P

of the driver IC.

Consequently, a greater output current can be obtained.

●

CONTROL SEQUENCE OF 1-2 OR W1-2 PHASE EXCITATION

To reduce vibration when the stepper motor is rotating, the

UDN2917EB can provide 1-2 or W1-2 phase excitation for the

control sequence without varying the V

REF

terminal voltage.

The step angle is

OUT

GND

Schottky barrier
diode

To motor

Combined vector (1/4 cycle)

Phase B

Phase A

(4)

(3)

(2)

(1)

(0)

Control sequence (1-2/W1-2 phase)

1/2 step : 1-2 excitation

About 1/4 step : W1-2 excitation

The control sequence is as shown below. (This sequence uses

threshold signal terminals Io and I

for PWM current control.)

UDN2917EB

2-Phase Stepper Motor Bipolar Driver IC (2-Phase/1-2 Phase/W1-2 Phase Excitation)

UDN2917EB

Note: The V

REF

terminal voltage cannot be set to 0 V. To make the output current ratio 0%, set I

=1.

When the sequence is 0, 8, 16, or 24, power-down can be set as follows:
I

=1, I

=0: Sequence No. 0 or 16

=1, I

=0: Sequence No. 8 or 24

(ENABLE1= ENABLE 2=0)

Phase A

Sequence

No.

Current ratio (%)

REF1

(V)

Current ratio (%)

REF2

(V)

Phase B

7.5

100

1.5

7.4

1.5

6.9

2.9

6.2

4.2

5.3

4.2

6.2

2.9

6.9

1.5

7.4

1.5

7.5

100

1.5

7.4

2.9

6.9

4.2

6.2

5.3

6.2

4.2

6.9

2.9

7.4

1.5

7.5

100

1.5

7.4

1.5

6.9

2.9

6.2

4.2

5.3

4.2

6.2

2.9

6.9

1.5

7.4

1.5

7.5

100

1.5

7.4

2.9

6.9

4.2

6.2

5.3

6.2

4.2

6.9

2.9

7.4

1.5

Control sequence (microstepping)

●

REF

terminal

REF

is the reference voltage input terminal for PWM constant

current control. To realize stable ensure a stable signal, make

sure noise is not applied to the terminal.

●

terminal

To prevent voltage spikes on the load power supply terminal

), connect a large capacitor (

≥

F) between the V

termi-

nal and ground as close to the device as possible. Make sure

the load supply voltage does not exceed 45V.

●

MICROSTEPPING (1/8 STEP) CONTROL SEQUENCE

Varying the V

REF

terminal voltage in steps provides 1/8

microstepping and reduces motor vibration greatly. The

microstepping control sequence is as follows:

●

Thermal protection

Thermal protection circuitry turns OFF all drivers when the junc-

tion temperature reaches +170

C. It is only intended to protect

the device from failures due to excessive junction temperature

and should not imply that output short circuits are permitted.

The output drivers are re-enabled when the junction tempera-

ture cools to +145

●

Around the ground

Since the UDN2917EB is a chopping type power driver IC, take

great care around the ground when mounting. Separate the

power system and the small signal (analog) system. Provide a

single-point connection to the GND terminal or a solid pattern of

low enough impedance.

A3955SB/SLB

2-Phase Stepper Motor Bipolar Driver ICs

A3955SB/SLB

■

Features

●

Maximum output ratings: 50V,

1.5A

●

Internal 3-bit non-linear DAC for 8-division

microstepping enables 2W1-2,W1-2, 1-2,

2-phase excitation drive without external

sine wave generator

●

Internal PWM current control in Mixed De-

cay mode (can also be used in Fast Decay

and Slow Decay mode), which improves

motor current response and stability with-

out deterioration of motor iron loss

●

External RC filter for sense terminal not

required thanks to internal blanking circuitry

●

Internal thermal shutdown, crossover-cur-

rent protection and transient-suppression

diodes

●

Special power-up and power-down se-

quencing for motor supply and logic sup-

ply not required

●

Employs copper batwing lead frame with

low thermal resistance

■

Absolute Maximum Ratings

Parameter

Symbol

Ratings

Units

A3955SB

A3955SLB

Load supply voltage

Output current (continuous)

1.5

Logic supply voltage

7.0

Logic/reference input

−

0.3 to V

+0.3

voltage range

Sense voltage

1.0

Package power dissipation

(Note1)

2.90

1.86

Operating temperature

−

20 to +85

Junction temperature

(Note2)

+150

Storage temperature

stg

−

55 to +150

●

Output current rating may be limited by duty cycle, ambient temperature, and heat sinking. Under any
set of conditions, do not exceed the specified current rating or a junction temperature of 150

Note 1: When ambient temperature is 25

C or over, derate using

−

23.26mW/

C(SB) or

−

14.93mW/

C(SLB).

Note 2: Fault conditions where junction temperature (T

) exceeds 150

C will activate the device’s thermal

shutdown circuitry. These conditions can be tolerated but should be avoided.

Allegro MicroSystems product

■

Terminal Connection Diagram

■

Derating

PFD

REF

GROUND

LOGIC

SUPPLY

PHASE

LOAD
SUPPLY

OUT

GROUND

SENSE

OUT

(TOP VIEW)

3.0

2.5

Allo

le pac

kage po

r dissipation P

[W]

1.5

0.5

Ambient temperature Ta (

−

100

A3955SLB 67

C/W

A3955SB 43

C/W

A3955SB/SLB

2W1-2 Phase Excitation/Micro-step Support

A3955SB/SLB

2-Phase Stepper Motor Bipolar Driver ICs (2W1-2 Phase Excitation/Micro-step Support)

A3955SB/SLB

■

Electrical Characteristics

(Unless specified otherwise, T

=25

C, V

=5V to 50V, V

=4.5V to 5.5V)

Parameter

Symbol

Conditions

Limits

Units

min

typ

max

Power outputs (OUT

or OUT

)

Load supply voltage range

Operating, I

1.5A, L=3mH

Vcc

Output leakage current

CEX

<1.0

=0V

−

1.0

−

SENSE

=1.0V : Source Driver, I

−

0.85A

1.0

1.2

Output saturation voltage

CE (sat)

SENSE

=1.0V : Source Driver, I

−

1.5A

1.3

1.5

SENSE

=1.0V : Sink Driver, I

=0.85A

0.5

0.6

SENSE

=1.0V : Sink Driver, I

=1.5A

1.3

1.5

Sense current offset

-I

, I

=0.85A, V

=0V, V

=5V

Clamp diode forward voltage

=0.85A

1.2

1.4

=1.5A

1.4

1.7

Motor supply current (No load)

BB (ON)

2.0

4.0

BB (OFF)

=0.8V

1.0

Control logic

Logic supply voltage range

Operating

4.5

5.0

5.5

Reference voltage range

REF

Operating

0.5

2.5

UVLO enable threshold

UVLOen

→

3.35

3.70

4.05

UVLO hysteresis

UVLOhys

0.30

0.45

0.60

Logic supply current

CC (ON)

CC (OFF)

=0.8V

Logic input voltage

2.0

0.8

Logic input current

=2.0V

<1.0

=0.8V

−

2.0

−

200

Slow Decay Mode

3.5

Mixed Decay comparator trip points

PFD

Mixed Decay Mode

1.1

3.1

Fast Decay Mode

0.8

Mixed Decay comparator input offset voltage

IO (PFD)

Mixed Decay compartor hysteresis

∆

IO (PFD)

Reference input current

REF

=0V~2.5V

5.0

Reference divider ratio

REF

at trip, D

=2V

3.0

DAC accuracy *1

DAC

ERR

REF

=1.0V~2.5V

3.0

REF

=0.5V~1.0V

4.0

Current-sense comparator input offset voltage *1

IO (S)

REF

=0V

5.0

=0.8V

=2.0V, D

=0.8V

19.5

=0.8V, D

=2V, D

=0.8V

38.2

Step reference current ratio

SRCR

=2V, D

=0.8V

55.5

=0.8V, D

=2V

70.7

=2V, D

=0.8V, D

=2V

83.1

=0.8V, D

=2V

92.4

=2V

100

Thermal shutdown temperature

165

Thermal shutdown hysteresis

∆

AC timing

PWM RC fixed off-time

OFFRC

=470pF, R

=43k

Ω

18.2

20.2

22.3

Current-Sense Comparator Trip to Source OFF,

PWM turn-off time

PWM (OFF)

=0.1A

1.0

1.5

Current-Sense Comparator Trip to Source OFF,

=1.5A

1.4

2.5

PWM turn-on time

PWM (ON)

Charge ON to Source ON, I

=0.1A

0.4

0.7

Charge ON to Source ON, I

=1.5A

0.55

0.85

PWM minimum on-time

ON (min)

=5.0V, R

≥

43k

Ω

, C

=470pF,

1.0

1.6

2.2

=0.1A

Crossover dead time

CODT

Ω

Load to 25V

0.3

1.5

3.0

*1: The total error for the V

REF

SENSE

function is the sum of the D/A error and the current-sense comparator input offset voltage.

●

“typ” values are for reference.

A3955SB/SLB

2-Phase Stepper Motor Bipolar Driver ICs (2W1-2 Phase Excitation/Micro-step Support)

A3955SB/SLB

■

Truth Table

■

Application Circuit

●

Off-time setting : t

OFF

≅

•

=12k

Ω

to 100k

Ω

=470pF to 1500pF

=0.39

Ω

to 0.62

Ω

=47

F+0.1

=0.1

REF

=0.5V to 2.5V

PFD

=1.1V to 3.1V (Mixed current-decay mode)

≥

3.5V (Slow current-decay mode)

≤

0.8V (Fast current-decay mode)

BRIDGE A

PFD

REF

36 k

Ω

36 k

Ω

560 pF

+5V

PHASE

CC1

BB1

47 F

LOGIC

0.5

Ω

0.5

Ω

BRIDGE B

BB2

PFD

REF

PHASE

CC2

+5 V

LOGIC

DAC

DAC DATA

DAC [%]

REF

100

3.00

92.4

3.25

83.1

3.61

70.7

4.24

55.5

5.41

38.2

7.85

19.5

15.38

All Outputs Disabled

where V

≅

TRIP

PHASE

PHASE

OUT

PFD

PFD

Operating Mode

≥

3.5V

Slow current-decay mode

1.1V to 3.1V

Mixed current-decay mode

≤

0.8V

Fast current-decay mode

■

Internal Block Diagram

PHASE

D/A

−

BLANKING
GATE

PWM LATCH

CURRENT-SENSE
COMPARATOR

MIXED-DECAY
COMPARATOR

PFD

SENSE

DISABLE

BLANKING

UVLO

& TSD

LOGIC

SUPPL

OUT

REF

OUT

GROUND

A3955SB/SLB

2-Phase Stepper Motor Bipolar Driver ICs (2W1-2 Phase Excitation/Micro-step Support)

A3955SB/SLB

■

Step Sequence

■

Current Vector Locus

Bridge A

Bridge B

Full

Half

Quarter

Eigth

Step

PHASE

LOADA

PHASE

LOADB

70.7%

55.5%

83.1%

38.2%

92.4%

19.5%

100%

−

19.5%

100%

−

38.2%

92.4%

−

55.5%

83.1%

−

70.7%

−

83.1%

55.5%

−

92.4%

38.2%

−

100%

19.5%

−

100%

−

100%

−

19.5%

−

92.4%

−

38.2%

−

83.1%

−

55.5%

−

70.7%

−

70.7%

−

55.5%

−

83.1%

−

38.2%

−

92.4%

−

19.5%

−

100%

−

100%

19.5%

−

100%

38.2%

−

92.4%

55.5%

−

83.1%

70.7%

−

70.7%

83.1%

−

55.5%

92.4%

−

38.2%

100%

−

19.5%

100%

19.5%

92.4%

38.2%

83.1%

55.5%

100

92.4

83.1

70.7

55.5

38.2

19.5

38.2

55.5

70.7

83.1 92.4

100

FULL STEP

7/8 STEP

3/4 STEP

5/8 STEP

1/2 STEP

3/8 S

1/4 STEP

1/8 STEP

100% CONST

ANT

TORQ

MAXIMUM FULL-STEP

CURRENT IN PERCENT

ORQ

UE (141%)

A3957SLB

2-Phase Stepper Motor Bipolar Driver IC

A3957SLB

■

Features

●

Maximum output ratings: 50V,

1.5A

●

Internal 4-bit non-linear DAC for 16-division

microstepping enables 4W1-2, 2W1-2, W1-

2, 2-phase excitation drive without exter-

nal sine wave generator

●

Internal PWM current control in Mixed De-

cay mode (can also be used in Fast Decay

and Slow Decay mode), which improves

motor current response and stability with-

out deterioration of motor iron loss

●

External RC filter for sense terminal not

required thanks to internal blanking circuitry

●

Internal thermal shutdown, crossover-cur-

rent protection and transient-suppression

diodes

●

Special power-up and power-down se-

quencing for motor supply and logic sup-

ply not required

●

Employs copper batwing lead frame with

low thermal resistance

■

Absolute Maximum Ratings

Parameter

Symbol

Ratings

Units

Load supply voltage

Output current (continuous)

1.5

Logic supply voltage

7.0

Logic/reference input

−

0.3 to V

+0.3

voltage range

Sense voltage

1.0

Package power dissipation P

(Note1)

2.23

Operating temperature

−

20 to +85

Junction temperature

(Note2)

+150

Storage temperature

stg

−

55 to +150

●

Output current rating may be limited by duty cycle, ambient temperature, and heat sinking. Under any
set of conditions, do not exceed the specified current rating or a junction temperature of 150

Note 1: When ambient temperature is 25

C or over, derate using

−

17.86mW/

Note 2: Fault conditions where junction temperature (T

) exceeds 150

C will activate the device’s thermal

shutdown circuitry. These conditions can be tolerated but should be avoided.

Allegro MicroSystems product

■

Terminal Connection Diagram

■

Derating

N.C.

PFD

REF

N.C.

GROUND

PHASE

N.C.

(TOP VIEW)

OUTB

N.C.

GROUND

SENSE

N.C.

OUTA

N.C.

2.5

Allo

le pac

kage po

r dissipation P

[W]

1.5

0.5

Ambient temperature Ta (

−

100

A3957S

C/W

4W1-2 Phase Excitation/Micro-step Support

A3957SLB

2-Phase Stepper Motor Bipolar Driver IC (4W1-2 Phase Excitation/Micro-step Support)

A3957SLB

■

Electrical Characteristics

(Unless specified otherwise, T

=25

C, V

=5V to 50V, V

=4.5V to 5.5V)

Parameter

Symbol

Conditions

Limits

Units

min

typ

max

Power outputs (OUT

or OUT

)

Load supply voltage range

Operating, I

1.5A, L=3mH

Vcc

Output leakage current

CEX

<1.0

=0V

−

1.0

−

SENSE

=1.0V : Source Driver, I

−

0.85A

1.0

1.2

Output saturation voltage

CE (sat)

SENSE

=1.0V : Source Driver, I

−

1.5A

1.4

1.5

SENSE

=1.0V : Sink Driver, I

=0.85A

0.5

0.7

SENSE

=1.0V : Sink Driver, I

=1.5A

1.2

1.5

Sense current offset

−

, I

=0.85A, V

=0V, V

=5V

Clamp diode forward voltage

=0.85A

1.2

1.4

=1.5A

1.5

1.7

Motor supply current (No load)

BB (ON)

2.0

4.0

BB (OFF)

=0.8V

1.0

Control logic

Logic supply voltage range

Operating

4.5

5.0

5.5

Reference voltage range

REF

Operating

0.5

2.5

UVLO enable threshold

UVLOen

→

3.35

3.70

4.05

UVLO hysteresis

UVLOhys

0.25

0.40

0.55

Logic supply current

CC (ON)

CC (OFF)

=0.8V

Logic input voltage

2.0

0.8

Logic input current

=2.0V

<1.0

=0.8V

−

2.0

−

200

Slow Decay Mode

3.5

Mixed Decay comparator trip point

PFD

Mixed Decay Mode

1.2

2.9

Fast Decay Mode

0.8

Mixed Decay comparator input offset voltage

IO (PFD)

Mixed Decay compartor hysteresis

∆

IO (PFD)

Reference input current

REF

=0V to 2.5V

5.0

Reference divider ratio

REF

at trip, D

=2V

3.0

DAC accuracy *1

DAC

ERR

REF

=1.0V to 2.5V

3.0

REF

=0.5V to 1.0V

4.0

Current-sense comparator input offset voltage *1

IO (S)

REF

=0V

−

=0.8V

=0.8V, D

=2.0V, D

=0.8V

17.4

=2.0V, D

=0.8V

26.1

=0.8V, D

=2V, D

=0.8V

34.8

=2.0V, D

=0.8V, D

=2.0V, D

=0.8V

43.5

=0.8V, D

=2.0V, D

=0.8V

52.2

=2.0V, D

=0.8V

60.9

Step reference current ratio

SRCR

=0.8V, D

=2.0V

69.6

=2.0V, D

=0.8V, D

=2.0V

73.9

=0.8V ,D

=2.0V, D

=0.8V, D

=2.0V

78.3

=2.0V, D

=0.8V, D

=2.0V

82.6

=0.8V, D

=2.0V

87.0

=2.0V, D

=0.8V, D

=2.0V

91.3

=0.8V, D

=2.0V

95.7

=2.0V

100

Thermal shutdown temperature

165

Thermal shutdown hysteresis

∆

AC timing

PWM RC fixed off-time

OFFRC

=470pF, R

=43k

Ω

18.2

20.2

22.3

Current-Sense Comparator Trip to Source OFF,

PWM turn-off time

PWM (OFF)

=0.1A

1.0

1.5

Current-Sense Comparator Trip to Source OFF,

=1.5A

1.4

2.5

PWM turn-on time

PWM (ON)

Charge ON to Source ON, I

=0.1A

0.4

0.7

Charge ON to Source ON, I

=1.5A

0.55

0.85

PWM minimum on-time

ON (min)

=5.0V, R

≥

43k

Ω

, C

=470pF,

1.0

1.6

2.2

=0.1A

Crossover dead time

CODT

Ω

Load to 25V

0.3

1.5

3.0

*1: The total error for the V

REF

SENSE

function is the sum of the D/A error and the current-sense comparator input offset voltage.

●

“typ” values are for reference.

A3957SLB

2-Phase Stepper Motor Bipolar Driver IC (4W1-2 Phase Excitation/Micro-step Support)

A3957SLB

■

Application Circuit

●

Off-time setting : t

OFF

≅

•

=36

Ω

(12k

Ω

to 100k

Ω

)

=560pF (470pF to 1500pF)

=0.51

Ω

(0.39

Ω

to 0.62

Ω

)

=100

F+0.1

=0.1

REF

=0.5V to 2.5V

PFD

=1.2V to 2.9V (Mixed current-decay mode)

≥

3.5V (Slow current-decay mode)

≤

0.8V (Fast current-decay mode)

Phase1

A3957SLB

6,7,

18,19

A3957SLB

6,7,

18,19

VBB

Vcc

D10

D11

D12

D13

REF1

PFD1

Phase2

D20

D21

D22

D23

REF2

PFD2

CT1

CT2

RT1

RT2

■

Internal Block Diagram

−

PFD

PHASE

OUT

MOTOR
SUPPLY

OUT

GND

(000X)

LEVEL

DAC

BLANKING

TIME AND

DRIVER

OFF

CONTROL

DECAY MODE

CONTROL

LOGIC

AND

LEVEL

SHIFT

UVLO

AND

TSD

REF

SENSE

Power Outputs

D3, D2, D1, D0

PHASE OUTA

OUTB

PFD

Power Output Operating Mode

0000 or 0001

Disable

≥

3.5V

Forward, slow current-decay mode

1.2V to 2.9V

Forward, mixed current-decay mode

≤

0.8V

Forward, fast current-decay mode

≥

3.5V

Reverse, slow current-decay mode

1.2V to 2.9V

Reverse, mixed current-decay mode

≤

0.8V

Reverse, fast current-decay mode

X: Don’t care
High impedance (source and sink both OFF)

■

Truth Table

DAC

DAC [%]

100

95.7

91.3

87.0

82.6

78.3

73.9

69.6

1XXX

X1XX

XX1X

DAC [%]

60.9

52.2

43.5

34.8

26.1

17.4

SI-7600/SI-7600D

3-Phase Stepper Motor Driver ICs

SI-7600/SI-7600D

■

Electrical Characteristics

■

Recommended Operating Voltage Ranges

■

Absolute Maximum Ratings

Parameter

Symbol

Ratings

Units

Load supply voltage

Logic supply voltage

Input voltage

−

0.3 to V

Reference input voltage

REF

−

0.3 to V

Sense voltage

sense

1.5

Package power dissipation

Junction temperature

−

20 to +85

Operating temperature

+125

Storage temperature

stg

−

55 to +125

Parameter

Symbol

Ratings

Units

Conditions

min

typ

max

Load supply voltage

Logic supply voltage

3.0

5.5

OL1

OL2

Output voltage

OH1

−

OH2

−

Load supply current

=5.5V

Logic supply current

=5.5V

Logic input voltage

3.75

1.25

Logic input current

0.75

−

0.25

Maximum clock frequency

200

kHz

Edge=0V

100

Edge=V

Slow

1.7

PFD input voltage

Mix

0.7

1.3

Fast

0.3

PFD input current

PFD

Reference input voltage

REF

−

Reference input current

REF

=0~Vcc

−

Sense voltage

REF

0.2

Mode=V

, V

REF

=0~V

−

REF

0.17

Mode=0V, AV

REF

=0~V

−

RC source current

220

Off time

off

1.1

Sec.

Parameter

Symbol

Ratings

Units

Load supply voltage

15 to 45

Logic supply voltage

3 to 5.5

Reference input voltage

REF

0.2 to Vcc

−

(Ta=25

Star Connection/Delta Connection

SI-7600/SI-7600D

3-Phase Stepper Motor Driver ICs (Star Connection/Delta Connection)

SI-7600/SI-7600D

■

Internal Block Diagram/Diagram of Standard External Circuit

■

Terminal Connection

The package shapes of SI-7600 and SI-7600D are different, however the terminal connection is the same.

■

External Dimensions

(Unless specified otherwise, all values are typical)

(Units: mm)

Pin No.

Name

Pin No.

Name

Pin No.

Name

Pin1

PFD

Pin8

Full/Half

Pin15

OLA

Pin2

Sense

Pin9

Enable

Pin16

OHC

Pin3

Vcc

Pin10

Mode

Pin17

OHB

Pin4

Reset

Pin11

REF

Pin18

OHA

Pin5

CW/CCW

Pin12

GND

Pin19

Pin6

Edge

Pin13

OLC

Pin20

Pin7

Clock

Pin14

OLB

REF

PFD

GND

MOS Array

ex. SLA5017 at 4A max

SLA5059 at 4A max

SLA5060 at 6A max

SLA5061 at 10A max

(Sanken)

OHA

OHB

OHC

OLA

OLB

OLC

Sense

Clock

CW/CCW

Reset

F/H

Ena

Edge

Mode

Vcc

Reference constants

Rs:0.1 to 1

Ω

(1 to 5W)

Rt:15k to 75k

Ω

Ct:420p to 1100pF

C1:10 F/10V

C2:100 F/63V

C3 to C6:0.01 to 1 F

C7:1000pF

R1+R2

≤

10k

Ω

REF

:0.2 to V

2-2V)

R3+R4

≤

10k

Ω

PFD

:0 to V

R5:10k

Ω

Current

Control

Control signal

Pri-

Buffer

Control

Logic

1/5

Buffer

PFD

VBB

Vcc

OHA

Reset

OHB

CW/CCW

OHA

EDGE

OLA

OLB

F/H

OLC

Ena

GND

Mode

REF

12.6

7.8

to 15

0.48

2.54

1.27 max

0.8 max

0.7

0.4

1.27

0.25

7.62

24.50

0.51 min

2.54 min

.08 max

6.30

5.5

2.2

max

0.89

SI-7600D

SI-7600

1.30

100

SI-7600/SI-7600D

3-Phase Stepper Motor Driver ICs (Star Connection/Delta Connection)

SI-7600/SI-7600D

1. Outline

The SI-7600/SI-7600D is a control IC used with a power MOS

FET array to drive a 3-phase stepper motor. Select the output-

stage MOS FET according to the rated current of the motor.

The full step is 2-phase excitation when this IC is in a star con-

nection but 3-phase excitation when it is in a delta connection.

2. Features

●

Suitable for both star connection drive and delta connection drive

●

Maximum load supply voltage V

=45V

●

Control logic supply voltage Vcc=3 to 5.5V

●

Supports star connection (2/2-3phase excitation) and delta

connection (3/2-3phase excitation)

●

Step switching timing by clock signal input

●

Forward/reverse, hold, and motor-free control

●

Step switching at the positive edge or positive/negative edge

of the clock signal

●

Control current automatic switching function for 2-3phase ex-

citation (effective for star connection)

(Current control: 86% for 2-phase excitation, 100% for 3-phase

excitation)

●

Self-excitation constant-current chopping by external C/R

●

Slow Decay, Mixed Decay, or Fast Decay selectable

●

Two package lineup: SOP (surface mounting) and DIP (lead

insertion)

SOP

…

SI-7600, DIP

…

SI-7600D

●

Maximum output current depends on the ratings of the MOS

FET array used

3. Input Logic Truth Table

Input terminal

Low level

High level

CW/CCW

CCW

Full/Half

2-3phase excitation

2-phase excitation

Enable

Disable

Enable

Mode

Always 100%

2-phase excitation: 85%

(Note 1)

3-phase excitation: 100%

Edge

Positive

Positive/negative

(Note 2)

Reset

Enable

Internal logic reset

(Note 3)

output disable

Select CW/CCW, Full/Half, or Edge when the clock level is low.

Note 1: The control current is always 85% for the full step (2-

phase excitation) when the Mode terminal level is high.

The value of 100% control current is calculated at the

REF

/(5

Rs) terminal because a 1/5 buffer is built into

the reference section.

Note 2: When the Edge terminal level is set high, the internal

counter increments both at the rising and falling edges.

Therefore, the duty ratio of the input clock should be set

at 50%.

Note 3: When the Reset terminal level is set high, the internal

counter is reset. Output remains disabled as long as the

Reset terminal level is high.

4. Determining the control current

The control current Io can be calculated as follows:

When the Mode terminal level is low

≅

REF

/(5

)

When the Mode terminal level is high

≅

REF

/(5

)

→

3-phase excitation

≅

REF

/(5.88

)

→

2-phase excitation

The reference voltage can be set within the range of 0.2V to Vcc

−

2V.

(When the voltage is less than 0.2V, the accuracy of the refer-

ence voltage divider ratio deteriorates.)

5. About the Current Control System (Setting the

Constant Ct/Rt)

The SI-7600 uses a current control system of the self-excitation

type with a fixed chopping OFF time.

The chopping OFF time is determined by the constant Ct/Rt.

The constant Ct/Rt is calculated by the formula

OFF

≅

1.1

……

(1)

The recommended range of constant Ct/Rt is as follows:

Ct: 420 to 1100pF

Rt: 15 to 75k

Ω

(Slow Decay or Mixed Decay

→

560pF/47k

Ω

, Fast Decay

→

470pF/20k

Ω

)

Usually, set T

OFF

to a value where the chopping frequency be-

comes about 30 to 40kHz.

The mode can be set to Slow Decay, Fast Decay, or Mixed De-

cay depending on the PFD terminal input potential.

PFD applied voltage and decay mode

PFD applied voltage

Decay mode

0 to 0.3V

Fast Decay

0.7V to 1.3V

Mixed Decay

1.7V to Vcc

Slow Decay

In Mixed Decay mode, the Fast/Slow time ratio can be set using

the voltage applied to the PFD terminal. The calculated values

are summarized below.

In this mode, the point of switching from Fast Decay to Slow

Decay is determined by the RC terminal voltage that determines

the chopping OFF time and by the PFD input voltage V

PFD

Formula (1) is used to determine the chopping OFF time.

The Fast Decay time is then determined by the RC discharge

time from the RC voltage (about 1.5V) to the PFD input voltage

PFD

) when chopping is turned from ON to OFF.

The Fast Decay time is

……

(2)

The Slow Decay time (t

OFFs

) is calculated by subtracting the value

of (2) from that of (1).

OFFS

≅

OFF

−

OFFf

……

(3)

Application Notes

OFFf

≅−

( )

PFD

1.5

101

SI-7600/SI-7600D

3-Phase Stepper Motor Driver ICs (Star Connection/Delta Connection)

SI-7600/SI-7600D

Ton

Toff

ITrip

OUT

1.5V

0.5V

Fast
Decay

PFD

Slow Decay

Ambient temperature Ta (

(W)

100

125

150

r dissipation P

Without heatsink

100

2mm Al heatsink

6. Method of Calculating Power Loss of Output

MOS FET

The SI-7600 uses a MOS-FET array for output. The power loss

of this MOS FET array can be calculated as summarized below.

This is an approximate value that does not reflect parameter

variations or other factors during use in the actual application.

Therefore, heat from the MOS FET array should actually be

measured.

●

Parameters for calculating power loss

To calculate the power loss of the MOS FET array, the following

parameters are needed:

(1) Control current Io (max)

(2) Excitation method

(3) Chopping ON-OFF time at current control: T

, T

OFF

, t

OFFf

: ON time, T

OFF

: OFF time, t

OFFf

: Fast Decay time at OFF)

(4) ON resistance of MOS FET: R

DS (ON)

(5) Forward voltage of MOS FET body diode: V

For (4) and (5), use the maximum values of the MOS FET speci-

fications.

(3) should be confirmed on the actual application.

●

Power loss of Pch MOS FETs

The power loss of Pch MOS FETs is caused by the ON resis-

tance and by the chopping-OFF regenerative current flowing

through the body diodes in Fast Decay mode.

(In Slow Decay mode, the chopping-OFF regenerative current

does not flow the body diodes.)

The losses are

ON resistance loss P1: P1=I

DS (ON)

Body diode loss P2: P2=I

With these parameters, the loss Pp per MOS FET is calculated

depending on the actual excitation method as follows:

a) 2-phase excitation (T=T

OFF

)

= (P1

/T+P2

OFFf

/T)

(1/3)

b) 2-3 phase excitation (T=T

OFF

)

= (P1

/T+P2

OFFf

/T)

(1/4)+(0.5

/T+P2

OFFf

(1/12)

●

Power loss of Nch MOS FETs

The power loss of Nch MOS FETs is caused by the ON resis-

tance or by the chopping-OFF regenerative current flowing

through the body diodes.

(This loss is not related to the current control method, Slow,

Mixed, or Fast Decay.)

The losses are

ON resistance loss N1: N1=I

DS(ON)

Body diode loss N2: N2=I

With these parameters, the loss P

per MOS FET is calculated

depending on the actual excitation method as follows:

a) 2-phase excitation (T=T

OFF

)

=(N1+N2

OFF

/T)

(1/3)

b) 2-3 phase excitation (T=T

OFF

)

=(N1+N2

OFF

/T)

(1/4)+(0.5N1+N2

OFF

/T)

(1/12)

●

Determining power loss and heatsink when SLA5017 is

used

If the SLA5017 is used in an output section, the power losses of

a Pch MOS FET and an Nch MOS FET should be multiplied by

three and added to determine the total loss P of SLA5017.

In other words, P=3

The allowable losses of SLA5017 are

Without heatsink: 5W

j-a=25

C/W

Infinite heatsink: 35W

j-c=3.57

C/W

Select a heatsink by considering the calculated losses, allow-

able losses, and following ratings:

When selecting a heatsink for SLA5017, be sure to check the

product temperature when in use in an actual applicaiton.

The calculated loss is an approximate value and therefore con-

tains a degree of error.

Select a heatsink so that the surface Al fin temperature of

SLA5017 will not exceed 100

C under the worst conditions.

Relationship between RC terminal voltage and output current

104

SI-7502

(SLA5011/SLA6503)

Part No.

Parameter

Symbol

Ratings

Units

Motor supply voltage

Auxiliary supply voltage

Control voltage

SI-7502

Reference voltage

ref

1.5

Detection voltage

Power dissipation

Ambient operating temperature

0 to +65

Drain -Source voltage

DSS

Drain current

SLA5011

Avalanche energy capability (Single pulse)

Power dissipation

Channel temperature

150

Storage temperature

stg

−

40 to +150

Collector-Base voltage

CBO

−

Collector-Emitter voltage

CEO

−

Emitter-Base voltage

EBO

−

Collector current

−

SLA6503

Collector current (Pulse)

C (pulse)

−

Base current

−

Power dissipation

Junction temperature

150

Storage temperature

stg

−

40 to +150

■

Electrical Characteristics

■

Absolute Maximum Ratings

5-Phase Stepper Motor Driver ICs

SI-7502

(SLA5011/SLA6503)

Pentagon Connection

=25

Part No.

Parameter

Symbol

Limits

Units

Conditions

min

typ

max

=42V, V

=5.5V

Supply current

12.5

=12.5V

=5.5V

Input current

IU-L

, I

IL-L

1.6

=0.4V

SI-7502

Upper drive circuit drive current

-on

=5V, AIU to EIU pin open

-off

=5V

Lower drive circuit voltage

-on

−

1.5

=5V, AIL to EIL pin open

-off

1.5

=5V

Oscillation frequency

kHz

=5V

Detection voltage

0.8

1.05

=5V, V

REF

pin open

Gate threshold voltage

2.0

4.0

=10V, I

=250

Forward Transconductance

e (yts)

2.2

3.3

=10V, I

=5A

DC ON-resistance

DS (ON)

0.17

0.22

Ω

=10V, I

=5A

SLA5011

Input capacitance

ISS

300

=25V, f=1.0MHz,V

=0V

Output capacitance

OSS

160

Di forward voltage between source and drain

1.1

1.5

=5A

Di reverse recovery time between source and drain

150

100mA

Collector cut-off current

CBO

−

60V

SLA6503

Collector-emitter voltage

CEO

−

10mA

DC current gain

2000

−

4V, I

−

Collector emitter saturation voltage

CE (sat)

1.5

−

3A, I

−

6mA

106

SI-7502

(SLA5011/SLA6503)

SI-7502

(SLA5011/SLA6503)

5-Phase Stepper Motor Driver ICs (Pentagon Connection)

41 (max)

P1.27

0.7

26=33.02

0.5

+0.15

−

0.05

1pin

27pin

0.3

+0.15

−

0.05

2.54

0.6

3.5

−

0.5

27pin

26pin

8(max)

30 (max)

R : 0.3mm

Pin-1 marking

(White dots)

Lot No.

Part No.

31.0

0.2

24.4

0.2

16.4

0.2

3.2

0.15

3.8

4.8

0.2

1.7

0.1

3.2

0.15

16.0

0.2

13.0

0.2

9.9

0.2

8.5max.

0.85

+0.2

−

0.1

1.45

0.15

P2.54

0.7

=27.94

1.0

9.5min (10.4)

1.2

0.15

31.5max.

1 2 3 4 5 6 7 8 9 10 11 12

Part No.

Lot No.

0.55

+0.2

−

0.1

2.2

0.7

Pin 1

2.7

0.8 max

(5V)

7407

Aiu

Biu

Ciu

Diu

Eiu

Ail

Bil

Cil

Dil

Eil

7406

+ C

1 12

(12V)

(15~42V)

Stepper Motor

: 100 F/63V
: 50 F/25V
: 10 F/10V
: 470pF
: 1k

Ω

: RK-34 (Sanken)

(typ)

OPD

(typ)

= 0.92/R

= (1.3

−

0.01) / Rs

= Vb

R' / (30000+R')

= 5100

Rx / (5100+Rx)

Active High

SI-7502

SLA5011

SLA6503

Excitation signal input

(Note) Dimensions marked with a # indicate dimensions of

lead tip.

■

Diagram of Standard External Circuit

■

External Dimensions

(Unit: mm)

■

External Dimensions

(Unit: mm)

SI-7502

SLA6503/SLA5011

107

SI-7502

(SLA5011/SLA6503)

SI-7502

(SLA5011/SLA6503)

5-Phase Stepper Motor Driver ICs (Pentagon Connection)

Fig. A

Waveform of output current

OH(max)

0.212

−

0.01

OH(min)

0.169

−

0.03

OH(max)

=5V)

OH(min)

=5V)

(

Ω

)

(A)

0.5

0.2

Sense resistor Rs

Output current I

RSH (max)

7.2

152.6+33.8

−

0.01

RSH (min)

6.1

152.6+33.8

−

0.03

RSH (max)

=5V)

)

=5V)

0.5

Ω

)

Variable current resistor Rx

0.2

1.0

0.8

0.6

0.4

(V)

Sense voltage V

RSH

to SI-7502

Sense resistor Rs

Fig. B Output current vs. Current sense resistor

Fig. C Sense voltage vs. Variable current resistor

Fig. D Coil current flow at pentagonal driving

■

Determining the Output Current I

(Control Current)

The main factors that determine the output current are current

sense resistor R

, supply voltage V

, and variable current resis-

tor R

(1) Normal mode

To operate a motor at the maximum current level, set R

infinity (open).

From Fig. A, when the maximum current ripple is designated

as I

, its value will be,

RSH

can be calculated as follows:

RSH

=0.19

−

0.03 (center value)

From equations (1) and (2), the output current I

can be

calculated as follows:

The relationship between I

and R

is shown in Fig. B.

(2) Power down mode

When an external resistor R

is connected, V

RSH

changes as

shown in Fig. C even when R

is retained. Obtain a power

down output current I

OHPD

from Fig. C and equation (1).

■

Relation between Output Current I

(Control

Current) and Motor Winding Current I

The SI-7502 uses the total current control system; therefore,

the output current I

is different from the motor winding current.

In a general pentagonal driving system, the current flows as

shown in Figure D. The relation between I

and I

is as follows:

With some driving systems, the relation can also be as follows:

RSH

Application Notes

............................... (2)

...................................................................... (1)

= (0.19

-0.03)