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Z-1 Foil Ultra High Precision Wrap-around Chip Resistor for

Improved Load Life Stability of 0.0025% (25 ppm) with TCR of

± 0.05 ppm/°C and withstands ESD of 25 KV min

FRSM Series of Precision Chip Resistors

Vishay Foil Resistors

Document Number: 63209

For any questions, contact:

foil@vishaypg.com

www.vishayfoilresistors.com

Revision: 8-Nov-12

INTRODUCTION

The FRSM is based on the new generation Z1- technology of
the Bulk Metal® Precision Foil resistor elements by Vishay
Precision Group (VPG), which makes these resistors
virtually insensitive to destabilizing factors. Their element,
based on the new Z-1 Foil is a solid alloy that displays the
desirable bulk properties of its parent material; thus, it is
inherently stable (remarkably improved load life stability of
25 ppm), noise-free and withstands ESD to 25KV or more.
The alloy is matched to the substrate and forms a single
entity with balanced temperature characteristics for an
unusually low and predictable TCR over a wide range from
-55 C° to more than 175C°. Resistance patterns are
photo-etched to permit trimming of resistance values to very
tight tolerances.

Our application engineering department is available to
advise and make recommendations. For non-standard
technical requirements and special applications, please
contact us using the e-mail address in the footer below.

FIGURE 1 - POWER DERATING CURVE

100

- 75

- 50

- 25

+ 25

+ 50

+ 75 + 100 + 125 + 150 + 175

Ambient Temperature (°C)

Rated Power (%)

+ 70 °C

- 55 °C

Lead (Pb)-free terminals

Tin/lead alloy terminals

FEATURES



Temperature coefficient of resistance (TCR):



0.05 ppm/°C typical (0 °C to + 60 °C)



0.2 ppm/°C typical (- 55 °C to + 125 °C, + 25 °C ref.)



Resistance tolerance: to ± 0.01 %



Power coefficient “



R due to self heating”:



5 ppm at rated power



Power rating: to 750 mW at + 70 °C



Load life stability:



± 0.0025 % at 70 °C, 2000 h at rated power.



± 0.005 % at 70 °C, 10,000 h at rated power.



Resistance Range: 5



to 125 k



(for higher and lower

values, please contact us)



Vishay Foil resistors are not restricted to standard values;

we can supply specific “as required” values at no extra cost

or delivery (e.g. 1K2345 vs. 1K)



Thermal stabilization time < 1 s (nominal value achieved

within 10 ppm of steady state value)



Electrostatic discharge (ESD) at least to 25kV



Short time overload: 0.005 %



Rise time: 1 ns effectively no ringing



Current noise: 0.010 µV

RMS

/V of applied voltage



(< - 40 dB)



Voltage coefficient: 0.1 ppm/V



Non inductive: 0.08 µH



Non hot spot design



Terminal finishes available: lead (Pb)-free, tin/lead alloy

(1)



Matched sets are available on request



Prototype quantities available in just 5 working days

or sooner. For more information, please contact

foil@vishaypg.com



For higher temperature application up to +240 °C and for

better performances, please contact us

TABLE 1 - TOLERANCE AND TCR VS.

RESISTANCE VALUE

(1)



(- 55 °C to + 125 °C, + 25 °C Ref.)

RESISTANCE

VALUE

(



)

TOLERANCE

(%)

TYPICAL TCR AND

MAX. SPREAD

(ppm/°C)

250



to 125K

± 0.01

± 0.2 ± 1.8

100



to < 250

± 0.02

± 0.2 ± 1.8



to < 100

± 0.05

± 0.2 ± 2.8



to < 50

± 0.1

± 0.2 ± 3.8



to < 25

± 0.25

± 0.2 ± 3.8



to < 10

± 0.5

± 0.2 ± 7.8

(1)

Pb containing terminations are not RoHS compliant, exemptions may apply

FRSM Series of Precision Chip Resistors

Vishay Foil Resistors

www.vishayfoilresistors.com

For any questions, contact:

foil@vishaypg.com

Document Number: 63209

Revision: 8-Nov-12

ABOUT THE FRSM

Several factors need to be considered when choosing a resistor for
applications that require long term stability, including TCR (ambient
temperature), Power TCR (self heating), load-life stability for more
than 10K hours (instead of the typical 1000 or 2000 hours load-life),

end-of-life tolerance (which is more important than the initial
tolerance), thermal EMF (low values, D.C), thermal stabilization and
ESD. Some precision resistor technologies such as Precision Thin
Film offer designers tight initial tolerances as low as 0.02 % but have
poor load life stability, high end-of-life tolerance, long thermal
stabilization, high drifts during operational life and ESD sensitivity.
Other resistor technologies, such as Wirewounds, provide low
absolute TCR and excellent current noise of -40 dB but have high
inductance and poor rise time (or thermal lag) for more than a few
seconds.

There are essentially only three resistance technologies widely used
for precision resistors in military and space applications:

Thin Film,

Wirewound and Bulk Metal® Foil.

Each has its own balance of

characteristics and costs that justify its selection in these
applications.

Thin Films are most cost-efficient within their normal

range of characteristics but have the highest TCR, highest noise and
have the least stability of the three technologies.

Wirewounds have

low noise, low TCR and a high level of stability at moderate cost but
also have high impedance and slow signal response.

Wirewounds

can also have a higher power density, but some stability is lost
through temperature cycling and load-life when made in smaller
configurations. Bulk Metal® Foil resistors have the lowest noise,
lowest TCR, highest stability and highest speed of any technology
but may have a higher cost, depending upon model. With Bulk
Metal® Foil resistors, savvy designers often save overall by
concentrating the circuit stability in the foil resistors where
exceptional stability allows for use of less-costly active devices---an
option not available with other resistor technologies because foil
requires a smaller total error budget through all cumulative resistor
life exposures.

Also, foil often eliminates extra circuitry added

merely for the purpose of correcting the limitations of other resistor
components. FRSM’s Bulk Metal® Foil resistors, based on new
generation technology and improved production methods starting
from February 2011, offer designers the complete set of top
performance characteristics to simplify circuitry and lower overall
system costs by reducing the number of required parts while
assuring a better end product. The new series of FRSM feature a
long-term load-life stability within 0.0025 % after 2000 hours and
0.005% after 10000 hours under full rated power at + 70 °C, first time
in the history of all resistor technologies. In addition to their low
absolute TCR of almost zero TCR , the devices offer Power TCR
(“



R due to self heating”) to ±5 ppm at rated power; tight tolerance

from 0.01% and thermal EMF of 0.05 µV/°C. Current design practice
has been to over specify resistors to allow for expected tolerance
degradation during service and there is a trend to move to
commercial off the shelf (COTS) parts instead of MIL spec Qualified
(QPL) parts.

Vishay Precision Group offers a new approach with

lower prices to bring Foil resistors within the reach of designers
whose end-of-life tolerance target is 0.05 % (total end of life
cumulative deviation from nominal) or less with COTS resistors
having all the inherent features for long term reliability.

While other resistor technologies can take several seconds or even
minutes to achieve a steady state thermal stabilization (thermal lag),
Vishay Foil resistors feature an almost instantaneous thermal
stabilization time and a nearly immeasurable 1 ns rise time
effectively with no ringing. The stress levels of each application are
different so the designer must make an estimation of what they might
be and assign a stress factor to each one.

The stress may normally

be low but for these purposes, we must assure that the installed
precision resistor is capable of reliability withstanding all potential
stresses.

For example, if the resistor is installed in a piece of

equipment that is expected to go out into an oil field in the back of a
pickup truck, shock and vibration and heat from the sun are obvious
factors.

The specific causes of resistor drift are listed in Table 4 and

the allowances shown are for full scale exposure. The designer may
choose to use a percentage of full scale stress factor if the
equipment will never see the full scale conditions.

For example, a

laboratory instrument that is expected to be permanently installed in
an air-conditioned laboratory does not need an end-of-life allowance
for excessive heat. There are other reasons for tolerancing the
resistors tighter than the initial calculation:

Measurement equipment

accuracy is traditionally ten times better than the expected accuracy
of the devices under test. So, these tighter tolerance applications
require a Foil resistor.

Also, the drift of the resistor without any

stress factor considerations results in a shift over time that must be
considered. FRSMs have the least amount of time shift.

The

manufacturer’s recommended recalibration cycle is a factor in the
saleability of the product and the longer the cycle, the more
acceptable the product.

Foil resistors contribute significantly to the

longer calibration cycle.

FIGURE 2 - TRIMMING TO VALUES*



(Conceptual Illustration)

Mutual Inductance
Reduction due
to Change in
Current Direction

Current Path

Before Trimming

Note:

Foil shown in black, etched spaces in white

Interloop Capacitance
Reduction in Series

Trimming Process

Removes this Material

from Shorting Strip Area

Changing Current Path

and Increasing

Resistance

Current Path

After Trimming

* To acquire a precision resistance value, the Bulk Metal® Foil chip
is trimmed by selectively removing built-in “shorting bars.” To
increase the resistance in known increments, marked areas are cut,
producing progressively smaller increases in resistance. This
method eliminates “hot spot” and improves the long term stability of
the resistor.

FIGURE 3 - TYPICAL RESISTANCE/

TEMPERATURE CURVE

(2)

(ppm)

+250

+200
+150
+100

+50

-50

-100
-150
-200
-250

+250
+200
+150
+100
+50
0

-50

-100
-150
-200
-250

-55

0.05 ppm/ºC

- 0.1 ppm/ºC

- 0.16 ppm/ºC

0.2 ppm/ºC

0.14 ppm/ºC

0.1 ppm/ºC

-25

+25

+65

+75

+100 +125

TABLE 3 - SPECIFICATIONS

(1)

CHIP



SIZE

RATED

POWER

(mW)

at + 70 °C

MAX.

WORKING

VOLTAGE

(



P R



)

RESISTANCE

RANGE

(



)

MAXIMUM

WEIGHT

(mg)

0402

(3)

5 V

100 to 500

0603

100

22 V

100 to 4K*

0805

200

40 V



to 8K

1206

300

87 V



to 25K

1506

300

95 V



to 30K

2010

500

187 V



to 70K

2512

750

220 V



to 125K

FRSM Series of Precision Chip Resistors

Vishay Foil Resistors

Document Number: 63209

For any questions, contact:

foil@vishaypg.com

www.vishayfoilresistors.com

Revision: 8-Nov-12

* For 0603 values between 4K and 5K, please contact us

TABLE 2 - DIMENSIONS

in Inches (Millimeters)

Top View

CHIP

SIZE

± 0.005 (0.13)

THICKNESS

MAXIMUM

± 0.005 (0.13)

0603

0.063 (1.60)

0.032 (0.81)

0.025 (0.64)

0.011 (0.28)

0805

0.080 (2.03)

0.050 (1.27)

0.025 (0.64)

0.015 (0.38)

1206

0.126 (3.20)

0.062 (1.57)

0.025 (0.64)

0.020 (0.51)

1506

0.150 (3.81)

0.062 (1.57)

0.025 (0.64)

0.020 (0.51)

2010

0.198 (5.03)

0.097 (2.46)

0.025 (0.64)

2512

0.249 (6.32)

0.127 (3.23)

0.025 (0.64)

0.032 (0.81)

Notes

(1)

For tighter performances and non-standard values up to 150K, please contact VPG application engineering using the e-mail addresses in the

footer below.

(2)

The TCR values for < 100



are influenced by the termination composition and result in deviation from this curve.

TABLE 4 - PERFORMANCES



TEST OR CONDITIONS



R LIMITS OF

PRECISION THIN FILM

TYPICAL



R LIMITS OF FRSM

SERIES

MAXIMUM



R LIMITS OF FRSM

SERIES

(3)

Thermal Shock, 100 x (- 65 °C to + 150 °C)

(see Figure 6)

± 0.1 %

± 0.005% (50 ppm)

± 0.01% (100 ppm)

Low Temperature Operation, - 65 °C, 45 min at P

nom

± 0.1 %

± 0.0025% (25 ppm)

± 0.005% (50 ppm)

Short Time Overload, 6.25 x Rated Power, 5 s

± 0.1 %

± 0.005% (50 ppm)

± 0.01% (100 ppm)

High Temperature Exposure, + 150 °C, 100 h

± 0.1 %

± 0.0025% (25 ppm)

± 0.005% (50 ppm)

Resistance to Soldering Heat, +245°C for 5 sec,+235°C

for 30 sec

± 0.1 %

± 0.005 % (50 ppm)

± 0.01% (100 ppm)

Moisture Resistance

± 0.1 %

± 0.003% (30 ppm)

± 0.01% (100 ppm)

Load Life Stability + 70 °C for 2000 h at Rated Power

(see Figure 8)

± 0.1 %

0.0025% (25 ppm)

± 0.005% (50ppm)

Load Life Stability + 70 °C for 10,000 h at Rated Power

± 0.5 %

0.005% (50 ppm)

± 0.015% (150ppm)

Note

(3)

As shown + 0.01



to allow for measurement errors at low values.

FIGURE 4 - RECOMMENDED MOUNTING

Notes

(1)

IR and vapor phase reflow are recommended.

(2)

Avoid the use of cleaning agents which could attack epoxy resins, which form part

of the resistor construction

(3)

Vacuum pick up is recommended for handling

(4)

If the use of a soldering iron becomes necessary, precautionary measures should

be taken to avoid any possible damage / overheating of the resistor

* Recommendation: The solder fillet profile should be such as to avoid running over

the top metallization

FRSM Series of Precision Chip Resistors

Vishay Foil Resistors

www.vishayfoilresistors.com

For any questions, contact:

foil@vishaypg.com

Document Number: 63209

Revision: 8-Nov-12

PULSE TEST

TEST DESCRIPTION

All parts baked at +125°C for 1 hr and allowed to cool at room
temperature for 1 hr, prior to testing. By using an electrolytic 0.01µF
capacitor charged to 1000 VDC, a single pulse was performed on 20
units of 1206, for each value: 100



, 1K



and 10K



of Surface

Mount Vishay Foil resistor and Thin Film resistor. The unit was
allowed time to cool down, after which the resistance measurement
was taken and displayed in ppm deviation from the initial reading.

TEST RESULTS

FIGURE 5 - PULSE TEST DESCRIPTION

!!!

!!+-

TABLE 5 - PULSE TEST RESULTS

VALUE

VOLTAGE

T= RC

AVERAGE DEVIATION

(%)

VISHAY

FOIL

RESISTOR

THIN
FILM

100R

1000VDC

1µsec

<0.001

Open

10 µsec

>35

10K

100 µsec

>0.008

FIGURE 6 - THERMAL SHOCK TEST

-20

100

∆

R (ppm)

Test per MIL PRF 55342 4.8.3 Mil STD 202, Method 107

Test Conditions: 100 X (-65°C to +150°C), n=10

1206

25K

0805

1206

2512

75K

ELECTROSTATIC DISCHARGE (ESD)

ESD can be categorized into three types of damages

Parametric Failure

- occurs when the ESD event alters one or more

device parameters (resistance in the case of resistors), causing it to
shift from its required tolerance. This failure does not directly pertain
to functionality; thus a parametric failure may be present while the
device is still functional.

Catastrophic Damage

- occurs when the ESD event causes the

device to immediately stop functioning. This may occur after one or
a number of ESD events with diverse causes, such as human body
discharge or the mere presence of an electrostatic field.

Latent Damage

- occurs when the ESD event causes moderate

damage to the device, which is not noticeable, as the device appears
to be functioning correctly. However, the load life of the device has
been dramatically reduced, and further degradation caused by
operating stresses may cause the device to fail during service.
Latent damage is the source for greatest concern, since it is very
difficult to detect by re-measurement or by visual inspection, since
damage may have occurred under the external coating.

FRSM Series of Precision Chip Resistors

Vishay Foil Resistors

Document Number: 63209

For any questions, contact:

foil@vishaypg.com

www.vishayfoilresistors.com

Revision: 8-Nov-12

TEST DESCRIPTION

By using a electrolytic 500 pF capacitor charged up to 4500 V,
pulses were performed on 10 units of 1206, 10K



of three different

Surface Mount Chip Resistors technologies, with an initial voltage
spike of 2500 V (Figure 7). The unit was allowed time to cool down,
after which the resistance measurement was taken and displayed in
ppm deviation from the initial reading. Readings were then taken in
500 V increments up to 4500 V.

TEST RESULTS

FIGURE 7 - ESD TEST DESCRIPTION

2500 V to 4500 V

500 pF

DMM

1 M

TABLE 6 - ESD TEST RESULTS

VOLTS

∆

R (%)

THICK FILM

THIN FILM

FOIL

2500

-2.7

<0.005

3000

-4.2

366

<0.005

3500

-6.2

>5000

<0.005

4000

-7.4

>5000

<0.005

4500

-8.6

OPEN

<0.005

FIGURE 8 - LOAD LIFE TEST FOR

2000 HRS @ +70°C
AT RATED POWER

-100

-80

-60

-40

-20

100

0 250 500 750 1000 1250 1500 1750 2000 2250

∆R (ppm)

Time (hrs)

0805-1K

0805-8K

1206-1K

1206-25K

2512-75K

2512-125K

POWER COEFFICIENT OF RESISTANCE
(PCR)

In precision resistors with low TCR, the self heating (Joule effect)
causes the resistor not to perform strictly to its TCR specifications.
This inaccuracy will result in an error at the end in the resistance
value under applied power. Vishay Foil Resistors introduced a new
concept of Power Coefficient of Resistance (PCR) along with a new
Z-Foil technology which leads to reduction of the sensitivity of
precision resistor to ambient temperature variations and changes of
applied power.

Figure 9 represents PCR behavior of three different resistor
technologies under applied power.

FIGURE 9 - BEHAVIOR OF THREE

DIFFERENT RESISTOR
TECHNOLOGIES UNDER
APPLIED POWER (POWER
COEFFICIENT TEST)

(ppm)

Applied power, (W)

0.1

0.2

0.3

0.4

0.5

+ 100 ppm

0 ppm

- 100 ppm

Thick Film

Surface

Mount Chip

Thin Film

Surface

Mount Chip

Z-Foil

Surface

Mount Chip

-------

Note: Size 1206, value: 1K

FIGURE 10 - CURRENT PATH IN A

RESISTIVE ALLOY

Noise generation is minimal when current

flow is through multiple paths as exists in

Bulk Metal

Foil resistive alloy.

FRSM Series of Precision Chip Resistors

Vishay Foil Resistors

www.vishayfoilresistors.com

For any questions, contact:

foil@vishaypg.com

Document Number: 63209

Revision: 8-Nov-12

POST MANUFACTURE OPERATIONS (PMO)

What is the importance of resistor stability in an electronic circuit?

Answer:

The circuit was probably not intended for just a onetime

use.

Also, the equipment may have to endure some environmental

and operational stresses. So, the ongoing use of the equipment is
expected and the more stable the resistors, the longer the time
before recalibrations. FRSM offers the most stability in all categories
but there is more than recalibration at stake here:

extremes of surge

voltage can cause thin film resistors to go open while the Foil resistor
based on the Z-1 technology is not affected.

An open means the

equipment must be returned to the maintenance department to have
the resistor replaced or, worse yet, mission failure. The cost of a Foil
resistor would have been insignificant compared to the cost of
mission failure or the cost of returning an instrument for repair or
replacement of a blown resistor.

Add to this the down time of the

equipment.

Designing for extended service - All electronic equipment is
expected to do something useful for a specified period of time.

the end of that period, and in spite of permissible service conditions,
the equipment is expected to still be functional in its intended service
and within its accuracy limits.

All the components contribute in some

way to the stability of the equipment but the resistors are the devices
relied upon most to retain the original accuracy of the equipment.

Any departure from the end-of-life accuracy limits set for one resistor
renders the entire equipment “out of service” and subject to repair or
recalibration. The prospect of repair or recalibration is unthinkable in
certain applications (space for example) and only devices that can
be given an appropriate initial tolerance with the expectation of
retaining proximity to the initial value throughout the service life are
suitable.

This is especially true of the resistors in a circuit which may

have power applied causing self heating, load applied for extended
periods or load life and load applied differentially from other resistors
resulting in a ratio offset.

The equipment itself may see elevated

temperatures for extended periods of storage.

Foil resistors are the

best solution when these factors come into play.

TABLE 7 - GLOBAL PART NUMBER INFORMATION

(1)

NEW GLOBAL PART NUMBER: Y402412K7560T9R (preferred part number format)

DENOTES PRECISION

VALUE

CHARACTERISTICS



= k



= standard



= lead (Pb)-free



1 to 999

= custom

PRODUCT CODE

RESISTANCE TOLERANCE

PACKAGING

4020

= FRSM0402

(2)

4021

= FRSM0603

4022

= FRSM0805

4023

= FRSM1206

4024

= FRSM1506

4025

= FRSM2010

4027

= FRSM2512

= ± 0.01 %



= ± 0.02 %



= ± 0.05 %



= ± 0.10 %



= ± 0.25 %



= ± 0.5 %



= ± 1.0 %

= tape and reel



= waffle pack

FOR EXAMPLE: ABOVE GLOBAL ORDER Y4024 12K7560 T 9 R:
TYPE: FRSM1506



VALUES: 12.7560 k



ABSOLUTE TOLERANCE: 0.01 %



TERMINATION: lead (Pb)-free



PACKAGING: tape and reel

HISTORICAL PART NUMBER: FRSM1506 12K756 TCR0.2 T S T (will continue to be used)

FRSM1506

12K756

TCR0.2

MODEL

RESISTANCE

VALUE

TCR

CHARACTERISTICS

TOLERANCE

TERMINATION

PACKAGING

FRSM0402

(2)

FRSM0603
FRSM0805
FRSM1206
FRSM1506
FRSM2010
FRSM2512

12.756 k



= ± 0.01 %



= ± 0.02 %



= ± 0.05 %



= ± 0.10 %



= ± 0.25 %



= ± 0.5 %



= ± 1.0 %

= lead (Pb)-free



= tin/lead

= tape and reel



= waffle pack

Note

(1)

For non-standard requests, please contact application engineering.

(2)

0402 is planned to be released to production at 2012.