Contents

Section 1

Section 2

Section 3

Section 4

Section 5

Section 6

Core Locator (Toroids) by Part Number 
Core Locator (Toroids) by Size
General Information

1-1 

Introduction

1-2 

Applications

1-3 

Core Identification

1-4 

General Powder Core Information

Core Selection

2-1 

Inductor Core Selection Procedure

2-2 

Core Selection Example

2-3 

Core Selection Charts

2-6

Designing with Magnetics Powder Cores

2-8

Powder Core Loss Calculation

Technical Data

 3-1 

Material Properties

3-2 

Conversion Tables

3-3 

Normal Magnetization Curves

3-6   Core Loss Density Curves

3-14   Permeability versus Temperature Curves
3-18

Permeability versus DC Bias Curves

3-21

Permeability versus AC Flux Curves

3-25

Permeability versus Frequency Curves

3-28

Wire Table

Core Data

4-1

Toroid Data

4-36 

Kool Mµ

®

 E Core Data

4-38 

Kool Mµ

®

 U Core Data

4-39 

Kool Mµ

®

 Segment Data

4-40 

MPP THINZ

®

 Data

Hardware

5-1 

 E Core Hardware

5-2    Toroid Hardware

General Winding Data

6-1    Winding Tables 

Index Pages

www.mag-inc.com 

I 

II 

MAGNETICS

MPP (Toroids)

Core Locator & Unit Pack Quantity

55014

4-4

10,000

55015

4-4

10,000

55016

4-4

10,000

55017

4-4

10,000

55018

4-4

10,000

55019

4-4

10,000

10,000

55020

4-4

10,000

55021

4-4

10,000

55022

4-4

10,000

55023

4-4

10,000

55024

4-8

10,000

55025

4-8

10,000

10,000

55026

4-8

10,000

55027

4-8

10,000

55028

4-8

10,000

55029

4-8

10,000

55030

4-8

10,000

55031

4-8

10,000

10,000

55032

4-8

10,000

55033

4-8

10,000

55034

4-8

10,000

55035

4-11

8,000

55036

4-11

8,000

55037

4-11

8,000

8,000

55038

4-11

8,000

55039

4-11

8,000

55040

4-11

8,000

55041

4-11

8,000

55042

4-11

8,000

55043

4-11

8,000

8,000

55044

4-11

8,000

55045

4-13

5,000

55046

4-13

5,000

55047

4-13

5,000

55048

4-13

5,000

55049

4-13

5,000

55050

4-13

5,000

55051

4-13

5,000

55052

4-13

5,000

55053

4-13

5,000

55059

4-17

1,000

55071

4-20

250

55076

4-22

220

55082

4-22

220

55083

4-23

180

55084

4-25

120

55086

4-25

120

55087

4-25

120

55088

4-25

120

55089

4-25

120

55090

4-25

120

55091

4-25

120

55092

4-25

120

55098

4-33

25

55099

4-33

25

55101

4-33

25

55102

4-33

25

55103

4-28

90

General Information

55104

4-28

90

55106

4-28

90

55107

4-28

90

55108

4-28

90

55109

4-28

90

55110

4-28

90

55111

4-28

90

55112

4-28

90

55114

4-28

90

55115

4-14

2,000

55116

4-14

2,000

55117

4-14

2,000

2,000

55118

4-14

2,000

55119

4-14

2,000

55120

4-14

2,000

55121

4-14

2,000

55122

4-14

2,000

55123

4-14

2,000

2,000

55124

4-14

2,000

55125

4-12

6,000

55127

4-12

6,000

55128

4-12

6,000

55129

4-12

6,000

55130

4-12

6,000

6,000

55131

4-12

6,000

55132

4-12

6,000

55133

4-12

6,000

55134

4-12

6,000

55135

4-1

7,500

55137

4-1

7,500

7,500

55138

4-1

7,500

55139

4-1

7,500

55140

4-1

7,500

55144

4-2

7,500

55145

4-2

7,500

55147

4-2

7,500

55148

4-2

7,500

55149

4-2

7,500

55150

4-2

7,500

55164

4-35

5

55165

4-35

5

55167

4-35

5

55168

4-35

5

55174

4-3

5,000

55175

4-3

5,000

55177

4-3

5,000

55178

4-3

5,000

55179

4-3

5,000

55180

4-3

5,000

55181

4-3

5,000

55190

4-27

80

55191

4-27

80

55192

4-27

80

55195

4-27

80

55196

4-27

80

55197

4-27

80

55198

4-27

80

55199

4-27

80

55200

4-16

1,600

55201

4-16

1,600

55202

4-16

1,600

55203

4-16

1,600

55204

4-16

1,600

55205

4-1 6

1,600

1,600

55206

4-16

1,600

55208

4-16

1,600

55209

4-16

1,600

55234

4-5

10,000

55235

4-5

10,000 

55236

4-5

10,000

10,000

55237

4-5

10,000

55238

4-5

10,000

55239

4-5

10,000

55240

4-5

10,000

55241

4-5

10,000

55242

4-5

10,000

10,000

55243

4-5

10,000

55248

4-23

180

55249

4-23

180

55250

4-23

180

55251

4-23

180

55252

4-23

180

55253

4-23

180

55254

4-23

180

55256

4-23

180

55257

4-23

180

55264

4-6

10,000

55265

4-6

10,000

10,000

55266

4-6

10,000

55267

4-6

10,000

55268

4-6

10,000

55269

4-6

10,000

55270

4-6

10,000

55271

4-6

10,000

55272

4-6

10,000

55273

4-6

10,000

55274

4-9

8,000

55275

4-9

8,000

55276

4-9

8,000 

55277

4-9

8,000

55278

4-9

8,000

55279

4-9

8,000

55280

4-9

8,000

55281

4-9

8,000

55282

4-9

8,000

55283

4-9

8,000

55284

4-9

8,000

55285

4-10

8,000

55286

4-10

8,000

55287

4-10

8,000

55288

4-10

8,000

55289

4-10

8,000

55290

4-10

8,000

55291

4-10

8,000

55292

4-10

8,000

55293

4-10

8,000

55304

4-17

1,000

55305

4-17

1,000

55306

4-17

1,000

55307

4-17

1,000

55308

4-17

1,000

55309

4-17

1,000

1,000

55310

4-17

1,000

55312

4-17

1,000

55313

4-17

1,000

55318

4-22

220

55319

4-22

220

55320

4-22

220

55321

4-22

220

55322

4-22

220

55323

4-22

220

55324

4-22

220

55326

4-22

220

55327

4-22

220

55336

4-34

10

55337

4-34

10

55339

4-34

10

55340

4-34

10

55344

4-18

480

55345

4-18

480

55347

4-18

480

55348

4-18

480

55349

4-18

480

55350

4-18

480

55351

4-18

480

55352

4-18

480

55353

4-18

480

55374

4-15

2,000

55375

4-15

2,000

55377

4-15

2,000

55378

4-15

2,000

55379

4-15

2,000

55380

4-15

2,000

55381

4-15

2,000

55382

4-15

2,000

55383

4-15

2,000

55404

4-7

10,000

55405

4-7

10,000

55407

4-7

10,000

55408

4-7

10,000

55409

4-7

10,000

55410

4-7

10,000

55411

4-7

10,000

55412

4-7

10,000

55413

4-7

10,000

55432

4-24

105

55433

4-24

105

55435

4-24

105

55436

4-24

105

55437

4-24

105

55438

4-24

105

55439

4-24

105

55440

4-24

105

55441

4-24

105

55542

4-20

250

55543

4-20

250

55544

4-20

250

55545

4-20

250

55546

4-20

250

55547

4-20

250

55548

4-20

250

55550

4-20

250

55551

4-20

250

55579

4-21

300

55580

4-21

300

55581

4-21

300

55582

4-21

300

55583

4-21

300

55584

4-21

300

55585

4-21

300

55586

4-21

300

55587

4-21

300

55588

4-21

300

55614

4-29

50

55615

4-29

50

55617

4-29

50

55620

4-29

50

55709

4-26

90

55710

4-26

90

55712

4-26

90

55713

4-26

90

55714

4-26

90

55715

4-26

90

55716

4-26

90

55717

4-26

90

55718

4-26

90

55734

4-30

20

55735

4-30

20

55737

4-30

20

55740

4-30

20

55848

4-16

1,600

55866

4-31

45

55867

4-31

45

55868

4-31

45

55869

4-31

45

55894

4-19

400

55906

4-32

40

55907

4-32

40

55908

4-32

40

55909

4-32

40

55924

4-19

400

55925

4-19

400

55926

4-19

400

55927

4-19

400

55928

4-19

400

55929

4-19

400

55930

4-19

400

55932

4-19

400

55933

4-19

400

P/N  PAGE 

QTY

 P/N  PAGE 

QTY  P/N  PAGE 

QTY

 P/N  PAGE 

QTY

 P/N  PAGE 

QTY

www.mag-inc.com 

III

High Flux (Toroids)

Core Locator & Unit Pack Quantity

58018

4-4

10,000

58019

4-4

10,000

58020

4-4

10,000

58021

4-4

10,000

58022

4-4

10,000

58023

4-4

10,000

10,000

58028

4-8

10,000

58029

4-8

10,000

58030

4-8

10,000

58031

4-8

10,000

58032

4-8

10,000

58033

4-8

10,000

10,000

58038

4-11

8,000

58039

4-11

8,000

58040

4-11

8,000

58041

4-11

8,000

58042

4-11

8,000

58043

4-11

8,000

8,000

58048

4-13

5,000

58049

4-13

5,000

58050

4-13

5,000

58051

4-13

5,000

58052

4-13

5,000

58053

4-13

5,000

5,000

58059

4-17

1,000

58071

4-20

250

58076

4-22

220

58083

4-23

180

58089

4-25

120

58090

4-25

120

58091

4-25

120

58092

4-25

120

58098

4-33

25

58099

4-33

25

58101

4-33

25

58102

4-33

25

58109

4-28

90

58110

4-28

90

58111

4-28

90

58112

4-28

90

58118

4-14

2,000

58119

4-14

2,000

58120

4-14

2,000

58121

4-14

2,000

58122

4-14

2,000

58123

4-14

2,000

58128

4-12

6,000

58129

4-12

6,000

58130

4-12

6,000

58131

4-12

6,000

58132

4-12

6,000

58133

4-12

6,000

58164

4-35

5

58165

4-35

5

58167

4-35

5

58168

4-35

5

58190

4-27

80

General Information

  P/N 

PAGE 

QTY

  P/N 

PAGE 

QTY

  P/N 

PAGE 

QTY

4-27

80

58192

4-27

80

58195

4-27

80

58204

4-16

1,600

58205

4-16

1,600

58206

4-16

1,600

1,600

58208

4-16

1,600

58209

4-16

1,600

58238

4-5

10,000

58239

4-5

10,000

58240

4-5

10,000

58241

4-5

10,000

10,000

58242

4-5

10,000

58243

4-5

10,000

58252

4-23

180

58253

4-23

180

58254

4-23

180

58256

4-23

180

58257

4-23

180

58268

4-6

10,000

58269

4-6

10,000

58270

4-6

10,000

58271

4-6

10,000

58272

4-6

10,000

10,000

58273

4-6

10,000

58278

4-9

8,000

58279

4-9

8,000

58280

4-9

8,000

58281

4-9

8,000

58282

4-9

8,000

8,000

58283

4-9

8,000

58288

4-10

8,000

58289

4-10

8,000

58290

4-10

8,000

58291

4-10

8,000

58292

4-10

8,000

58293

4-10

8,000

58308

4-17

1,000

58309

4-17

1,000

58310

4-17

1,000

58312

4-17

1,000

58313

4-17

1,000

58322

4-22

220

58323

4-22

220

58324

4-22

220

58326

4-22

220

58327

4-22

220

58336

4-34

10

58337

4-34

10

58339

4-34

10

58340

4-34

10

58348

4-18

480

58349

4-18

480

58350

4-18

480

58351

4-18

480

58352

4-18

480

58353

4-18

480

58378

4-15

2,000

58379

4-15

2,000

58380

4-15

2,000

58381

4-15

2,000

58382

4-15

2,000

58383

4-15

2,000

2,000

58408

4-7

10,000

58409

4-7

10,000

58410

4-7

10,000

58411

4-7

10,000

58412

4-7

10,000

58413

4-7

10,000

10,000

58437

4-24

105

58438

4-24

105

58439

4-24

105

58440

4-24

105

58441

4-24

105

58546

4-20

250

58547

4-20

250

58548

4-20

250

58550

4-20

250

58551

4-20

250

58583

4-21

300

58584

4-21

300

58585

4-21

300

58586

4-21

300

58587

4-21

300

58588

4-21

300

58614

4-29

50

58615

4-29

50

58617

4-29

50

58620

4-29

50

58714

4-26

90

58715

4-26

90

58716

4-26

90

58717

4-26

90

58718

4-26

90

58734

4-30

20

58735

4-30

20

58737

4-30

20

58740

4-30

20

58848

4-16

1,600

58866

4-31

45

58867

4-31

45

58868

4-31

45

58869

4-31

45

58894

4-19

400

58906

4-32

40

58907

4-32

40

58908

4-32

40

58909

4-32

40

58928

4-19

400

58929

4-19

400

58930

4-19

400

58932

4-19

400

58933

4-19

400

General Information

Kool Mµ

®

 (Toroids)

Core Locator & Unit Pack Quantity

77020

4-4

10,000

77021

4-4

10,000

77030

4-8

10,000

77031

4-8

10,000

77040

4-11

8,000

77041

4-11

8,000

8,000

77050

4-13

5,000

77051

4-13

5,000

77054

4-13

5,000

77055

4-13

5,000

77059

4-17

1,000

77071

4-20

250

77076

4-22

220

77083

4-23

180

77089

4-25

120

77090

4-25

120

77091

4-25

120

77093

4-25

120

77094

4-25

120

77095

4-25

120

77098

4-33

25

77099

4-33

25

77100

4-33

25

77102

4-33

25

77109

4-28

90

77110

4-28

90

77111

4-28

90

77120

4-14

2,000

77121

4-14

2,000

77130

4-12

6,000

6,000

77131

4-12

6,000

77140

4-1

7,500

77141

4-1

7,500

77150

4-2

7,500

77151

4-2

7,500

77154

4-2

7,500

77155

4-2

7,500

77165

4-35

5

77166

4-35

5

77180

4-3

5,000

77181

4-3

5,000

77184

4-3

5,000

77185

4-3

5,000

77189

4-27

80

77191

4-27

80

77192

4-27

80

77193

4-27

80

77194

4-27

80

77195

4-27

80

77206

4-16

1,600

77210

4-16

1,600

77211

4-16

1,600

77212

4-28

90

77213

4-28

90

  P/N 

PAGE 

QTY

  P/N 

PAGE 

QTY

  P/N 

PAGE 

QTY

4-28

90

77224

4-14

2,000

77225

4-14

2,000

77240

4-5

10,000

77241

4-5

10,000

77244

4-5

10,000

10,000

77245

4-5

10,000

77254

4-23

180

77256

4-23

180

77258

4-23

180

77259

4-23

180

77260

4-23

180

77270

4-6

10,000

77271

4-6

10000

77280

4-9

8,000

77281

4-9

8,000

77290

4-10

8,000

77291

4-10

8,000

8,000

77294

4-10

8,000

77295

4-10

8,000

77310

4-17

1,000

77312

4-17

1,000

77314

4-17

1,000

77315

4-17

1,000

1,000

77316

4-17

1000 

77324

4-22

220

77326

4-22

220

77328

4-22

220

77329

4-22

220

77330

4-22

220 

77334

4-12

6,000

77335

4-12

6,000

   77337

4-34

10

77338

4-34

10

77339

4-34

10

77350

4-18

480

77351

4-18

480

77352

4-18

480

77354

4-18

480

77355

4-18

480

77356

4-18

480 

77380

4-15

2,000

77381

4-15

2,000

77384

4-15

2,000

77385

4-15

2,000

77410

4-7

10,000

77411

4-7

10,000

77414

4-7

10,000

10,000

77415

4-7

10,000

77431

4-24

105

77438

4-24

105

77439

4-24

105

77440

4-24

105

77442

4-24

105

77443

4-24

105

77444

4-1

7,500

77445

4-1

7,500

77548

4-20

250

77550

4-20

250

77552

4-20

250

77553

4-20

250

77555

4-20

250

77585

4-21

300

77586

4-21

300

77587

4-21

300

77589

4-21

300

77590

4-21

300

77591

4-21

300

77615

4-29

50

77616

4-29

50

77617

4-29

50

77618

4-29

50

77619

4-29

50

77715

4-26

90

77716

4-26

90

77717

4-26

90

77719

4-26

90

77720

4-26

90

77721

4-26

90

77735

4-30

20

77736

4-30

20

77737

4-30

20

77738

4-30

20

77739

4-30

20

77824

4-4

10,000

77825

4-4

10,000

77834

4-8

10,000

77835

4-8

10,000

77844

4-11

8,000

77845

4-11

8,000

77847

4-16

1,600 

  77848

4-16

1,600

77867

4-31

45

77868

4-31

45

77872

4-31

45

77874

4-6

10,000

77875

4-6

10,000

77884

4-6

10,000

77885

4-6

10,000

77894

4-19

400

77906

4-32

40

77907

4-32

40

77908

4-32

40

77912

4-32

40

77930

4-19

400

77932

4-19

400

77934

4-19

400

77935

4-19

400

77936

4-19

400

IV 

MAGNETICS

Section

XF

LUX

® 

(Toroids)

Core Locator & Unit Pack Quantity

General Information

78051

4-13

5,000

78059

4-17

1,000

78071

4-20

250

78076

4-22

220

78083

4-23

180

78090

4-25

120

  P/N 

PAGE 

QTY

  P/N 

PAGE 

QTY

  P/N 

PAGE 

QTY

4-28

90

78121

4-14

2,000

78192

4-27

80

78351

4-18

480

78381

4-21

2,000

78439

4-24

105 

78586

4-21

300

78716

4-26

90

78848

4-16

1,600

78867

4-31

45

78894

4-19

400

78907

4-32

40

www.mag-inc.com 

V

 

9.65

4.78

3.18

55283

58283

77281

-

    

 

 

55282

58282

77885

-

 

 

 

 

55281

58281

77884

-

 

 

 

 

55280

58280

77280

-

 

 

 

 

55279

58279

-

-

 

 

 

 

55278

55278

-

-

 

 

 

 

55274

-

-

-

 

 

 

 

55277

-

-

-

 

 

 

 

55276

-

-

-

 

 

 

 

55275

-

-

-   

9.65

4.78

3.96

55293

58293

77291

-

 

 

 

 

55292

58292

77295

-

 

 

 

 

55291

58291

77294

-

 

 

 

 

55290

58290

77290

-

 

 

 

 

55289

58289

-

-

 

 

 

 

55288

55288

-

-

 

 

 

 

55284

-

-

 

 

 

 

55287

-

-

-

 

 

 

 

55285

-

-

-

 

 

 

 

55286

-

-

-

10.2

5.08

3.96

55043

58043

77041

 

 

 

 

55042

58042

77845

-

 

 

 

 

55041

58041

77844

-

 

 

 

 

55040

58040

77040

-

 

 

 

 

55039

58039

-

-

 

 

 

 

55038

58038

-

-

 

 

 

 

55034

-

-

 

 

 

 

55037

-

-

-

 

 

 

 

55035

-

-

-

 

 

 

 

55036

-

-

-   

11.2

6.35

3.96

55133

58133

77131

 

 

 

 

55132

58132

77335

-

 

 

 

 

55131

58131

77334

-

 

 

 

 

55130

58130

77130

-

 

 

 

 

55129

58129

-

-

 

 

 

 

55128

58128

-

-

 

 

 

 

55124

-

-

 

 

 

 

55127

-

-

-

 

 

 

 

55125

-

-

-   

12.7

7.62

4.75

55053

58053

77051

78051

 

 

 

 

55052

58052

77055

-

 

 

 

 

55051

58051

77054

-

 

 

 

 

55050

58050

77050

-

 

 

 

 

55049

58049

-

-

 

 

 

 

55048

58048

-

-

 

 

 

 

55044

-

-

 

 

 

 

55047

-

-

-

 

 

 

55045

-

-

-

 

 

 

 

55046

-

-

-   

16.6

10.2

6.35

55123

58123

77121

78121

 

 

 

 

55122

58122

77225

-

 

 

 

 

55121

58121

77224

-

 

 

 

 

55120

58120

77120

-

 

 

 

 

55119

58119

-

-

 

 

 

 

55118

58118

-

-

 

 

 

 

55114

-

-

 

 

 

 

55117

-

-

-

 

 

 

 

55115

-

-

-

 

 

 

 

55116

-

-

-   

17.3

9.65

6.35

55383

58383

77381

78381

 

 

 

 

55382

58382

77385

-

 

 

 

 

55381

58381

77384

-

 

 

 

 

55380

58380

77380

-

 

 

 

 

55379

58379

-

-

 

 

 

 

55378

58378

-

-

 

 

 

 

55374

-

-

-

 

 

 

 

55377

-

-

-

 

 

 

 

55375

-

-

-

Powder Core Locator by Size (mm)

General Information

 

3.56

1.78

1.52

55140

-

77140

-

 

 

 

 

55139

 -

77141 

-

 

 

 

 

55138 

- 

77444 

-

 

 

 

 

55134

 - 

77445 

-

 

 

 

 

55137

 - 

- 

-

 

 

 

 

55135

 - 

- 

-

3.94 

2.24 

2.54 

55150

 - 

77151 

-

 

 

 

 

55149

 - 

77155 

-

 

 

 

 

55148 

- 

77154 

-

 

 

 

 

55144 

- 

77150 

-

 

 

 

 

55147 

- 

- 

-

 

 

 

 

55145 

- 

- 

-

4.65 

2.36 

2.54 

55181

 - 

77181

 -

 

 

 

 

55180 

- 

77185

 -

 

 

 

 

55179 

- 

77184 

-

 

 

 

 

55178

 - 

77180 

-

 

 

 

 

55174 

- 

- 

-

 

 

 

 

55177 

- 

- 

-

 

 

 

 

55175 

- 

-

 -

6.35

2.79

2.79

55023

58023

77021

-

 

 

 

 

55022

58022

77825

-

 

 

 

 

55021

58021

77824

-

 

 

 

 

55020

58020

77020

-

 

 

 

 

55019

58019

-

-

 

 

 

 

55018

58018

-

-

 

 

 

 

55014

-

-

-

 

 

 

 

55017

-

-

-

 

 

 

 

55015

-

-

-

 

 

 

 

55016

-

-

-

6.6

2.67

2.54

55243

58243

77241

-

 

 

 

 

55242

58242

77245

-

 

 

 

 

55241

58241

77244

-

 

 

 

 

55240

58240

77240

-

 

 

 

 

55239

58239

-

-

 

 

 

 

55238

58238

-

-

 

 

 

 

55234

-

-

-

 

 

 

 

55237

-

-

-

 

 

 

 

55235

-

-

-

 

 

 

 

55236

-

-

-

6.6

2.67

4.78

55273

58273

77271

-

 

 

 

 

55272

58272

77875

-

 

 

 

 

55271

58271

77874

-

 

 

 

 

55270

58270

77270

-

 

 

 

 

55269

58269

-

-

 

 

 

 

55268

58268

-

-

 

 

 

 

55264

-

-

-

 

 

 

 

55267

-

-

-

 

 

 

 

55265

-

-

-

 

 

 

 

55266

-

-

-

6.86

3.96

5.08

55413

58413

77411

-

 

 

 

 

55412

58412

77415

-

 

 

 

 

55411

58411

77414

-

 

 

 

 

55410

58410

77410

-

 

 

 

 

55409

58409

-

-

 

 

 

 

55408

58408

-

-

 

 

 

 

55404

-

-

-

 

 

 

 

55407

-

-

-

 

 

 

 

55405

-

-

-

7.87

3.96

3.18

55033

58033

77031

-

 

 

 

 

55032

58032

77035

-

 

 

 

 

55031

58031

77034

-

 

 

 

 

55030

58030

77030

-

 

 

 

 

55029

58029

-

-

 

 

 

 

55028

58028

-

-

 

 

 

 

55024

58024

-

-

 

 

 

 

55027

-

-

-

 

 

 

 

55026

-

-

-

 

 

 

 

55025

-

-

-

  OD 

ID  HT  MPP  High Flux  Kool Mµ

®

  XF

LUX

®

  OD 

ID  HT  MPP  High Flux  Kool Mµ

®

  XF

LUX

®

140 SIZE PAGE 4-1

280 SIZE PAGE 4-9

290 SIZE PAGE 4-10

040 SIZE PAGE 4-11

130 SIZE PAGE 4-12

050 SIZE PAGE 4-13

120 SIZE PAGE 4-14

150 SIZE PAGE 4-2

180 SIZE PAGE 4-3

020 SIZE PAGE 4-4

240 SIZE PAGE 4-5

270 SIZE PAGE 4-6

410 SIZE PAGE 4-7

030 SIZE PAGE 4-8

380 SIZE PAGE 4-15

The tool set for each size of core can be used to make a full range of materials and permeabilities. Magnetics denotes each 

tool set bt the 125µ core made with it. Exception OD > 4” 

VI 

MAGNETICS

 

20.3

12.7

6.35

55209

58209

77847

78848

 

 

 

 

55208

58208

77848

-

 

 

 

 

55848

58848

77211

-

 

 

 

 

55206

58206

77210

-

 

 

 

 

55205

58205

77206

-

 

 

 

 

55204

58204

-

-

 

 

 

 

55200

-

-

-

 

 

 

 

55203

-

-

-

 

 

 

 

55201

-

-

-

 

 

 

 

55202

-

-

-   

22.9

14.0

7.62

55313

58313

77312

78059

 

 

 

 

55312

58312

77316

-

 

 

 

 

55059

58059

77059

-

 

 

 

 

55310

58310

77315

-

 

 

 

 

55309

58309

77314

-

 

 

 

 

55308

58308

77310

-

 

 

 

 

55304

-

-

-

 

 

 

 

55307

-

-

-

 

 

 

 

55305

-

-

-

 

 

 

 

55306

-

-

-   

23.6

14.4

8.89

55353

58353

77352

78351

 

 

 

 

55352

58352

77356

-

 

 

 

 

55351

58351

77351

-

 

 

 

 

55350

58350

77355

-

 

 

 

 

55349

58349

77354

-

 

 

 

 

55348

58348

77350

-

 

 

 

 

55344

-

-

-

 

 

 

 

55347

-

-

-

 

 

 

 

55345

-

-

-   

26.9

14.7

11.2

55933

58933

77932

78894

 

 

 

 

55932

58932

77936

-

 

 

 

 

55894

58894

77894

-

 

 

 

 

55930

58930

77935

-

 

 

 

 

55929

58929

77934

-

 

 

 

 

55928

58928

77930

-

 

 

 

 

55924

-

-

 

 

 

 

55927

-

-

-

 

 

 

 

55925

-

-

-

 

 

 

 

55926

-

-

-   

32.8

20.1

10.7

55551

58551

77550

78071

 

 

 

 

55550

58550

77555

-

 

 

 

 

55071

58071

77071

-

 

 

 

 

55548

58548

77553

-

 

 

 

 

55547

58547

77552

-

 

 

 

 

55546

58546

77548

-

 

 

 

 

55542

-

-

-

 

 

 

55545

-

-

-

 

 

 

 

55543

-

-

-

 

 

 

 

55544

-

-

-   

34.3

23.4

8.89

55588

58588

77587

78586

 

 

 

 

55587

58587

77591

-

 

 

 

 

55586

58586

77586

-

 

 

 

 

55585

58585

77590

-

 

 

 

 

55584

58584

77589

-

 

 

 

 

55583

58583

77585

-

 

 

 

 

55579

-

-

-

 

 

 

 

55582

-

-

-

 

 

 

 

55580

-

-

-

 

 

 

 

55581

-

-

- -

35.8

22.4

10.5

55327

58327

77326

78076

 

 

 

 

55326

58326

77330

-

 

 

 

 

55076

58076

77076

-

 

 

 

 

55324

58324

77329

-

 

 

 

 

55323

58323

77328

-

 

 

 

 

55322

58322

77324

-

 

 

 

 

55318

-

-

-

 

 

 

 

55321

-

-

-

 

 

 

 

55319

-

-

-

 

 

 

 

55320

-

-

-

Powder Core Locator by Size (mm)

350 SIZE PAGE 4-18

930 SIZE PAGE 4-19

548 SIZE PAGE 4-20

585 SIZE PAGE 4-21

324 SIZE PAGE 4-22

310 SIZE PAGE 4-17

206 SIZE PAGE 4-16

 

39.9

24.1

14.5

55257

58257

77256

78083

 

 

 

 

55256

58256

77260

-

 

 

 

 

55083

58083

77083

-

 

 

 

 

55254

58254

77259

-

 

 

 

 

55253

58253

77258

-

 

 

 

 

55252

58252

77254

-

 

 

 

 

55248

-

-

-

 

 

 

 

55251

-

-

-

 

 

 

 

55249

-

-

-

 

 

 

 

55250

-

-

-   

46.7

24.1

18.0

55441

58441

77440

78439

 

 

 

 

55440

58440

77431

-

 

 

 

 

55439

58439

77439

-

 

 

 

 

55438

58438

77443

-

 

 

 

 

55437

58437

77442

-

 

 

 

 

55436

-

77438

-

 

 

 

 

55432

-

-

-

 

 

 

 

55435

-

-

-

 

 

 

 

55433

-

-

-

46.7

28.7

15.2

55092

58092

77091

78090

 

 

 

 

55091

58091

77095

-

 

 

 

 

55090

58090

77090

-

 

 

 

 

55089

58089

77094

-

 

 

 

 

55088

-

77093

-

 

 

 

 

55087

-

77089

-

 

 

 

 

55082

-

-

-

 

 

 

 

55086

-

-

-

 

 

 

 

55084

-

-

-

50.8

31.8

13.5

55718

58718

77717

78716

 

 

 

 

55717

58717

77721

-

 

 

 

 

55716

58716

77716

-

 

 

 

 

55715

58715

77720

-

 

 

 

 

55714

58714

77719

-

 

 

 

 

55713

-

77715

-

 

 

 

 

55709

-

-

-

 

 

 

 

55712

-

-

-

 

 

 

 

55710

-

-

-

57.2

26.4

15.2

55190

58190

77191

78192

 

 

 

 

55191

58191

77189

-

 

 

 

 

55192

58192

77192

-

 

 

 

 

55195

58195

77193

-

 

 

 

 

55196

-

77194

-

 

 

 

 

55197

-

77195

-

 

 

 

 

55198

-

-

-

 

 

 

 

55199

-

-

-

57.2

35.6

14.0

55112

58112

77111

78110

 

 

 

 

55111

58111

77212

-

 

 

 

 

55110

58110

77110

-

 

 

 

 

55109

58109

77214

-

 

 

 

 

55108

-

77213

-

 

 

 

 

55107

-

77109

-

 

 

 

 

55103

-

-

-

 

 

 

 

55106

-

-

-

 

 

 

 

55104

-

-

-

62.0

32.6

25.0

55614

58614

77615

-

 

 

 

 

55615

58615

77616

-

 

 

 

 

55617

58617

77617

-

 

 

 

 

55620

58620

77618

-

 

 

 

 

-

-

77619

-

74.1

45.3

35.0

55734

58734

77735

-

 

 

 

 

55735

58735

77736

-

 

 

 

 

55737

58737

77737

-

 

 

 

 

55740

58740

77738

-

 

 

 

 

-

-

77739

-

  OD 

ID  HT  MPP  High Flux  Kool Mµ

®

  XF

LUX

®

  OD 

ID  HT  MPP  High Flux  Kool Mµ

®

  XF

LUX

®

254 SIZE PAGE 4-23

438 SIZE  PAGE 4-24

089 SIZE  PAGE 4-25

715 SIZE  PAGE 4-26

195 SIZE  PAGE 4-27

109 SIZE  PAGE 4-28

740 SIZE  PAGE 4-30

620 SIZE  PAGE 4-29

General Information

 Core Locator by Size Table continued...

The tool set for each size of core can be used to make a full range of materials and permeabilities. Magnetics denotes each 

tool set bt the 125µ core made with it. Exception OD > 4” 

www.mag-inc.com 

VII

General Information

Powder Core Locator by Size (mm)

  OD 

ID  HT  MPP  High Flux  Kool Mµ

®

  XF

LUX

®

 

77.8

49.2

12.7

55869

58869

77868

78867

 

 

 

 

55868

 

58868

77872

-

 

 

 

 

55867

58867

77867

-

 

 

 

 

55866

58866

-

-

77.8

49.2

15.9

55909

58909

77908

78907

 

 

 

 

55908

58908

77912

-

 

 

 

 

55907

58907

77907

-

 

 

 

 

55906

58906

77906

-

101.6

57.2

16.5

55101

58101

77102

-

 

 

 

 

55102

58102

77100

-

 

 

 

 

55099

58099

77099

-

 

 

 

 

55098

58098

77098

-    

866 SIZE  PAGE 4-31

102 SIZE  PAGE 4-33

165 SIZE  PAGE 4-35

906 SIZE  PAGE 4-32

tool set bt the 125µ core made with it. Exception OD > 4” 

 

132.6

78.6

25.4

55336

58336

77337

-

 

 

 

 

55337

58337

77338

-

 

 

 

 

55339

58339

77339

-

 

 

 

 

55340

58340

-

-

165.1 102.4

31.7

55164

58164

77165

-

 

 

 

 

55165

58165

77166

-

 

 

 

 

165 SIZE  PAGE 4-35

165 SIZE  PAGE 4-35

55167

58167

-

-

  OD 

ID  HT  MPP  High Flux  Kool Mµ

®

  XF

LUX

®

337 SIZE  PAGE 4-34

VIII 

MAGNETICS

www.mag-inc.com

 1-1

General Information

Introduction

Magnetics Molypermalloy Powder (MPP)

 cores are 

distributed air gap toroidal cores made from a 81% nickel, 
17% iron, and 2% molybdenum alloy powder for the lowest 
core losses of any powder core material.  MPP cores (and all 
powder cores) exhibit soft saturation, which is a significant 
design advantage compared with gapped ferrites.  Also, 
unlike ferrites, the MPP saturation curve does not need to 
be derated with increasing device temperature.

MPP cores possess many outstanding magnetic 
characteristics, such as high resistivity, low hysteresis and 
eddy current losses, excellent inductance stability after high 
DC magnetization or under high DC bias conditions and 
minimal inductance shift under high AC excitation.

MPP THINZ

®

, or washer cores, put the premium 

performance of Magnetics’ superior MPP material into 
robust, low height toroid form, for low profile inductors.  
With MPP THINZ, exact permeability and height are 
easily adjusted to result in the optimum design for each 
application.

Magnetics High Flux

 powder cores are distributed air 

gap toroidal cores made from a 50% nickel - 50% iron alloy
powder for the highest biasing capability of any powder 
core material. High Flux cores have advantages that result 
in superior performance in certain applications involving high 
power, high DC bias, or high AC excitation amplitude.  The 
High Flux alloy has saturation flux density that is twice that 
of MPP alloy, and three times or more than that of ferrite.  As 
a consequence, High Flux cores can support significantly 
more DC Bias current or AC flux density.

High Flux offers much lower core losses and superior DC 
bias compared with powdered iron cores.  High Flux cores 
offer lower core losses and similar DC bias compared with 
XF

LUX

 cores.

Frequently, High Flux allows the designer to reduce the size 
of an inductive component compared with MPP, powdered 
iron, or ferrite.

Magnetics Kool Mµ

®

 powder cores are distributed air gap 

cores made from a ferrous alloy powder for low losses at 
elevated frequencies.  The near zero magnetostriction alloy 
makes Kool Mµ ideal for eliminating audible frequency noise in 
filter inductors.  In high frequency applications, core losses of 
powdered iron, for instance, can be a major factor in contributing 
to undesirable temperature rises.  Kool Mµ cores are superior 
because their losses are significantly less, resulting in lower 
temperature rises.  Kool Mµ cores generally offer a reduction 
in core size, or an improvement in efficiency, compared with 
powdered iron cores.

Inductors built with Kool Mµ cores do not have several of the 
disadvantages that are inherent with gapped ferrite cores:

1.

Ferrite saturation flux density is 0.5T or less, which is less 
than half of the flux density of Kool Mµ alloy.  This results 
in much less energy storage possible in the same volume 
with ferrite.

2.

Moreover, saturation flux density in ferrites is reduced 
significantly at elevated temperatures, but in Kool Mµ it is 
not.

3.

Ferrites exhibit sharp saturation, and thus risk complete 
collapse of inductance above a certain safe current level.  
Kool Mµ’s saturation is soft, allowing for safe design to 
much higher currents.

4.

 

Fringing losses at the discrete air gap in a ferrite inductor 
can be disastrous, a problem that is completely absent 
with Kool Mµ.

Kool Mµ is available in a variety of core types, for maximum 
flexibility.  Toroids offer compact size and self-shielding.   E cores 
and U cores afford lower cost of winding, use of foil inductors, 
and ease of fixturing. Very large cores and structures are available 
to support very high current applications.  These include toroids 
and racetrack shapes up to 102 mm, 133 mm and 165 mm; 
jumbo E cores; stacked shapes; and blocks.

Magnetics XF

LUX

®

 distributed air gap cores are made from 

6.5% silicon iron powder.  A true high temperature material, with 
no thermal aging, XF

LUX

 offers lower losses than powdered iron 

cores and superior DC bias performance.  The soft saturation 
of X

F

LUX

 material offers an advantage over ferrite cores.  XF

LUX

 

cores are ideal for low and medium frequency chokes where   
inductance at peak load is critical.

MAGNETICS

1-2

General Information

Applications

Magnetics powder cores are most commonly used in power 
inductor applications, specifically in switch-mode power 
supply (SMPS), filter inductors, also known as DC inductors, 
or chokes.  Other Power applications include differential 
inductors, boost inductors, buck inductors and flyback 
transformers.

While all four materials are used in these applications, each 
has its own advantage.  For the lowest loss inductor, MPP 
material should be used since it has the lowest core loss.  
For the smallest core size in a DC bias dominated design, 

High Flux material should be used since it has the highest 
flux capacity.  XF

LUX

®

 can be a lower cost alternative to High 

Flux, in situations where the higher core losses and more 
limited permeability availability of XF

LUX

 is acceptable.

The unique advantages of Magnetics’ powder cores are 
used in a variety of other applications, including:  High Q 
filters, temperature stabilized filters and inductors, high 
reliability inductors and filters, high temperature inductors 
and filters, high current current transformers, telecom filters 
and load coils.

A lower cost family of alternative products to Magnetics’ four premium powder core materials are powdered irons.  Manufacturers 
of powdered iron use a different production process.  For comparison with the above table, powdered irons have permeabilities 
from 10 -100; highest core loss; good perm vs. DC bias; fair temperature stability; lower temperature ratings; soft saturation; 0% 
nickel content; lowest relative cost.

MPP

High Flux

Kool Mµ

®

XF

LUX

®

Permeability

14-550

14-160

26-125

60

Core Loss

Lowest

Moderate

Low

High

Perm vs. DC Bias

Better

Best

Good

Best

Temperature Stability

Best

Very Good

Very Good

Good

Temperature Rating

200° C continuous

200° C continuous

200° C continuous

200° C continuous

Saturation Characteristic 

Soft

Soft

Soft

Soft

Nickel Content

81%

50%

0%

0%

Relative Cost

High 

Medium

Low

Low

www.mag-inc.com

 1-3

Core Identification

General Information

All Magnetics powder cores have unique part numbers that provide important information about the characteristics of the cores. A 
description of each type of part number is provided below.

Core Finish Code

Voltage Breakdown* Material Availability

OD Size Availability

Permeability Availability

1,000 volts min

MPP, High Flux

1,000 volts min

MPP, High Flux

All

All

A7

1,000 volts min

Kool Mµ

1,000 volts min

Kool Mµ

®

, XF

LUX

®

All

All

AY

600 volts min

All

3.56 - 16.5 mm

14µ - 300µ

A5

2,000 volts min

MPP, High Flux

2,000 volts min

MPP, High Flux

>4.65 mm

All

A9

8,000 volts min

MPP, High Flux

8,000 volts min

MPP, High Flux

>4.65 mm

All

D4

1,000 volts min

MPP

>4.65 mm

60µ - 200µ

W4

1,000 volts min

MPP

>4.65 mm

60µ - 200µ

M4

1,000 volts min

MPP

>4.65 mm

60µ - 200µ

L6

1,000 volts min

MPP

>4.65 mm

60µ - 300µ

T O R O I D S

CO55206A2

E CORES and THINZ

00K5528E060

LARGE E CORES and SEGMENTS

00K130LE026 

* No voltage breakdown min for A2 or A7 with OD 

)

 4.65mm

   
Catalog Number (designates size and permeability)
Material Code  . . . .  55 = MPP

58 = High Flux

77 = Kool Mµ

78 = XF

LUX

Grading Code . . . . .  CO = Graded into 2% inductance bands – OD <5 mm, 5% bands

00 = Not graded

Permeability Code ... Permeability, e.g. 060 for 60µ
Shape Code . . . . . . E = E Core

T = Toroid

T = T

T = T

U = U Core

P = I Core/Plate

B = Block

Size Code . . . . . . . First two digits equal approximate length 

or OD in mm / Last two digits equal 

approximate height or ID in mm

Material Code . . . . . M = MPP

H = High Flux
K = Kool Mµ
X = XF

LUX

Grading Code . . . . .  00 = Not graded

Permeability Code . . Permeability, e.g. 026 for 26µ
Shape Code . . . . . . LE = Large E Core

TC = Toroid

TC = T

TC = T

RT = Race Track

IS = I Segment

AR = Arc Segment

Size Code
Material Code . . . . . M = MPP

H = High Flux

K = Kool Mµ

X = XF

LUX

Grading Code . . . . . 00 = Not graded

Size 

(O.D. mm)

6-digit  

Shop Order Number

2-digit  

Material Code

3-digit 

Catalog Number

2-digit 

Core Finish Code

Inductance  

Code

Inductance  

Example

6.35 - 6.86

123456  020 +6

7.87 - 12.7

123456  050A2 +6

> 12.7

123456  55120A2 +6

Powder Core Toroid Stamping Summary

s )NDUCTANCE #ODE IS ONLY STAMPED ON -00 TOROIDS WITH #/ 'RADING #ODE

s #ORES WITH /$ LESS THAN  MM ARE NOT STAMPED

s &ULL PART NUMBER AND SHOP ORDER NUMBER ARE STAMPED ON ALL SHAPES

s 3HOP ORDER NUMBER IDENTIlES THE PRODUCT BATCH ENSURING TRACEABILITY OF EVERY

core through the entire manufacturing process, back to raw materials

MAGNETICS

1-4

Core Coating

General Information

Magnetics toroidal powder cores are coated with a special 
epoxy finish that provides a tough, wax tight, moisture 
and chemical resistant barrier having excellent dielectric 
properties.  Parylene coating is also offered.

The finish is tested for voltage breakdown by inserting the core 
between two weighted wire mesh pads. Force is adjusted 
to produce a uniform pressure of 10 psi, simulating winding 
pressure. The test condition for each core in the random 
sample set, to guarantee minimum breakdown voltage in each 
production batch, is 60 Hz rms voltage at 1.25 the guaranteed 
limit. A2 and A7 samples are tested to 1250 V min wire-to-wire. 
AY samples are tested to 750 V min wire-to-wire.

Magnetics powder cores are precision manufactured to 
an inductance tolerance of ± 8%*, using standard Kelsall 
Permeameter Cup measurements and a precision series 
inductance bridge.

MPP and High Flux cores with outside diameters > 4.65 
mm are graded into 2% inductance bands as a standard 
practice at no additional charge.  Core grading can reduce 
winding costs by minimizing turns adjustments when 
building high turns inductors to very tight inductance 
specifications.  MPP cores 4.65 mm and smaller are graded 
into 5% bands.  14µ cores, 26µ cores, MPP THINZ

®

 and 

parylene coated cores are not graded.

Graded Magnetics MPP cores and High Flux cores are also 
available with tolerances tighter than the standard ± 8%.

*Kool Mµ cores with outside diameters less than 12.7 mm 

have wider tolerances.

Material

Color

Core Finish Codes

MPP

Gray

A2, A5, A9, D4, M4, W4, L6

High Flux

Khaki

High Flux

Khaki

A2, A5, A9

Kool Mµ

®

 

Black

 

Black

A7

XF

LUX

®

Brown

A7

Brown

A7

Higher minimum breakdown coatings can be applied upon 
request for cores larger than 4.65 mm.

Toroids as large as 16.5 mm outside diameter can be 
coated with parylene to minimize the constriction of the 
inside diameter.  All finished dimensions in this catalog are 
for epoxy coating (A2 or A7).  For a parylene coated toroid 
(AY), the maximum OD and HT are reduced by 0.18 mm 
(0.007”), and the minimum ID is increased by 0.18 mm 
(0.007”).

The maximum steady-state operating temperature for epoxy 
coating is 200°C.  The maximum steady-state operating 
temperature for parylene coating is 130°C, but it can be 
used as high as 200°C for short periods, such as during 
board soldering. High temperature operation of Magnetics 
powder cores does not affect magnetic properties. 

MPP, High Flux, Kool Mµ, and XF

LUX

 materials can be 

operated continuously at 200°C with no aging or damage.

Core Inductance Tolerance and Grading

+8

+8

+7

-4.0

-3.5

+8

+8

+7

-4.0

-3.5

+8

+8

+7

-4.0

-3.5

+8

+8

+7

-4.0

-3.5

+8

+8

+7

-4.0

-3.5

+6

+7

+5

-3.5

-2.5

+6

+7

+5

-3.5

-2.5

+6

+7

+5

-3.5

-2.5

+6

+7

+5

-3.5

-2.5

+6

+7

+5

-3.5

-2.5

+4

+5

+3

-2.5

-1.5

+4

+5

+3

-2.5

-1.5

+4

+5

+3

-2.5

-1.5

+4

+5

+3

-2.5

-1.5

+4

+5

+3

-2.5

-1.5

+2

+3

+1

-1.5

-0.5

+2

+3

+1

-1.5

-0.5

+2

+3

+1

-1.5

-0.5

+2

+3

+1

-1.5

-0.5

+2

+3

+1

-1.5

-0.5

+0

+1

-1

-0.5

+0.5

+0

+1

-1

-0.5

+0.5

+0

+1

-1

-0.5

+0.5

+0

+1

-1

-0.5

+0.5

+0

+1

-1

-0.5

+0.5

-2

-1

-3

+0.5

+1.5

-2

-1

-3

+0.5

+1.5

-2

-1

-3

+0.5

+1.5

-2

-1

-3

+0.5

+1.5

-2

-1

-3

+0.5

+1.5

-4

-3

-5

+1.5

+2.5

-4

-3

-5

+1.5

+2.5

-4

-3

-5

+1.5

+2.5

-4

-3

-5

+1.5

+2.5

-4

-3

-5

+1.5

+2.5

-6

-5

-7

+2.5

+3.5

-6

-5

-7

+2.5

+3.5

-6

-5

-7

+2.5

+3.5

-6

-5

-7

+2.5

+3.5

-6

-5

-7

+2.5

+3.5

-8

-7

-8

+3.5

+4.0

-8

-7

-8

+3.5

+4.0

-8

-7

-8

+3.5

+4.0

-8

-7

-8

+3.5

+4.0

-8

-7

-8

+3.5

+4.0

GRADE 

Stamped 

on Core 

OD

INDUCTANCE 

% Deviation 

from Nominal

From

From

To

To

TURNS 

% Deviation 

from Nominal

www.mag-inc.com

 1-5

General Information

A

L

 and Inductance Calculation

The nominal inductance of a wound core can be calculated 
from the core geometry by using the following equation:

Magnetics inductance standards are measured in a Kelsall 
Permeameter Cup.  Actual wound inductance measured 
outside a Kelsall Cup is greater than the nominal calculated 
value due to leakage flux and flux developed by the current 
in the winding. The difference depends on many variables;  
core size, permeability, core coating thickness, wire size 
and number of turns, in addition to the way in which the 
windings are put on the core.  The difference is negligible 
for permeabilities above 125 and turns greater than 500.  
However, the lower the permeability and/or number of turns, 
the more pronounced this deviation becomes.

Example : C055930A2 (26.9 mm, 125µ)

The following formula can be used to approximate the leakage 
flux to add to the expected inductance.  This formula was 
developed from historical data of cores tested at Magnetics.  
Be aware that this will only give an approximation based on 
evenly spaced windings.  You may expect as much as a ±50% 
deviation from this result.

Example C055930A2 with 25 turns (p. 4-19)

The inductance for a given number of turns is related to the 
inductance factor listed in the catalog by:

Measured vs. Calculated Inductance

where:

L =  inductance (µH)

µ  = core permeability

N  =  number of turns

A

e

=  core cross section (mm

2

)

l

e

=  core magnetic path length (mm)

where:

L

LK

=  leakage inductance adder (µH)

N  =  number of turns

A

e

=  core cross section (mm

2

)

l

e

=  core magnetic path length (mm)

where:

L

N

=  inductance for N turns (µH)

A

L

= inductance factor (nH/T

2

) 

N  =  number of turns

        0.292 N

1.065

 A

e

                  l

e

L

N

 =         A

L

N

2

10

-3

Number  

of Turns

Calculated  

Inductance

Measured  

Inductance

157 mH

+0.0%

500

39.3 mH

+0.5%

300

14.1 mH

+1%

100

1.57 mH

+3%

50

393 µH

+5%

25

98.1 µH

+9%

Catalog Data

Calculated  

Inductance

Leakage 

Adder

Estimated 

Measured  

Inductance

A

L

 = 157 nH/T

2

A

e

 = 65.4 mm

2

l

e

 = 63.5 mm

L

N

 = (157)(25)

2

10

-3

= 98.1 µH

         0.292(25)

1.065

(65.4)

63.5 

=    9.3 µH

L = L

N

 + L

LK

= 98.1 + 9.3

= 107 µH

L

LK

 =

L

         0.292(25)

         0.292(25)

LK

 =

MAGNETICS

1-6

General Information

MPP Temperature Stabilization 

Magnetics MPP cores are provided in three basic 
temperature stabilizations: Standard, Controlled and Linear.

The core finish code is used to designate the stabilization, 
although the coating itself has no influence on the 
temperature stabilization performance of the core.  A2, A7, 
AY, A5 and A9 are standard; D4, W4, and M4 are controlled 
stabilization, and L6 is linear stabilization.  See page 1-3 for 
size and permeability availability.

Inductance of standard MPP cores exhibits a small, positive 
temperature coefficient.  This is due to the permeability vs. 
temperature characteristic of the magnetic alloy, and to 
the thermal expansion response of the distributed air gap 
formed by the insulating material surrounding metal powder 
grains.

The inductance of controlled stabilization MPP cores (codes 
D4, W4 and M4) exhibits nearly flat temperature coefficient 
within defined temperature ranges.  This is accomplished 
with adjustments in the alloy chemistry, unique to Magnetics.  
Cost is higher than for standard cores, but there is no 

M4 cores meet the W4 limits and may be substituted in place of W4.

Stability limit example:  When the 2mT, 10kHz inductance of a W4 stabilized core is measured at all temperature stops between 
-55°C and +85°C, the difference between the highest value and the lowest value cannot exceed 0.50% of the inductance at 25°C.  
L6 ppm slopes are referenced to 25°C.

impact on any electrical or physical properties apart from the 
flattened inductance curve.

The typical applications for stabilized cores are tuned 
filters, where very consistent inductance over temperature 
is required.  The flat inductance performance of controlled 
stabilization cores is apparent only at low drive levels, less 
than 10 mT. Consequently, there is no performance benefit 
to using stabilized cores at higher drive levels, for example in 
power chokes.

L6 code, linear stabilization, was originally developed to 
match the temperature coefficient of polystyrene capacitors, 
permitting the design of passive filters that are very stable 
over a wide temperature range, even though the capacitors 
shift.

Initial inductance and initial inductance stability are sensitive 
to external factors such as moisture and physical stress.  
See Precision Inductor Processing on page 1-7.

Part Number Suffix

Stabilization Type

Guaranteed Inductance Stability Limits

Stabilized Temperature Range

D4

Controlled

±0.1%

0° to +55°C

W4

Controlled

±.25%

-55°C to +85°C

M4

Controlled

±.25%

-65°C to +125°C

L6

Linear

+25 to +90 ppm/°C 

+65 to +150 ppm/°C

-55°C to +25°C 

+25°C to +85°C

L6

Linear (300µ)

+25 to +110 ppm/°C 
+65 to +180 ppm/°C

-55°C to +25°C 

+25°C to +85°C

www.mag-inc.com

 1-7

General Information

Precision Inductor Processing

Magnetics MPP cores possess excellent stability.  Under 
typical shelf life conditions the initial inductance of an 
unpotted core will shift less than 0.5%.

If maximum stability is desired, the following procedures 
will remove physical stresses and core moisture, leading to 
inductance stabilities better than 0.05%

The application where these precautions are used is typically 
high turns precision filter inductors, operating at low drive 
levels.  Power inductors would see no benefit, as they do 
not operate near the initial permeability of the core, nor do 
they generally require the same precision.  

1.

Wind cores to the approximate specified inductance 
(slightly over the desired value).

2.

Cool wound cores to -60°C.  
Maintain at temperature for 20 minutes to help relieve 
winding stresses caused by high winding tension, large 
wire, or many turns.

3.

Heat cores slowly (<2°C/minute) to 115°C.  
Maintain at temperature for 20 minutes.

4.

Steps 2 and 3 should be repeated twice. 

5.

Bake at 115°C for 16 hours.

6.

Cool to room temperature and adjust turns to obtain 
specified inductance.

7.

Cores must be kept dry until potted or hermetically 
sealed.

8.

If the cores are to be potted, they should be covered 
first with cushioning material, such as silicone rubber.  
This material minimizes the possibility of the potting 
compound stressing the core and changing the 
inductance value.

9.

Potting compounds should be chosen with care, as 
even semi-flexible resins can cause core stresses and 
reduce stability.  Selection should be based on minimum 
shrinkage and minimum moisture absorption.

Cor

e Selection

2-1

MAGNETICS

Only two parameters of the design application must be 
known to select a core for a current-limited inductor;  induc-
tance required with DC bias and the DC current.  Use the 
following procedure to determine the core size and number 
of turns.

1. 

 Compute the product of LI

2

 where:  

L = inductance required with DC bias (mH)  
I = DC current (A)

2. 

 Locate the LI

2

 value on the Core Selector Chart 

(page 2-3, 2-4, & 2-5).  Follow this coordinate to the 
intersection with the first core size that lies above the 
diagonal permeability line. This is the smallest core size 
that can be used.

3. 

 The permeability line is sectioned into standard avail-
able core permeabilities.  Selecting the permeability 
indicated will tend to be the best trade-off between A

L

 

and DC bias.

4. 

 Inductance, core size, and permeability are now 
known.  Calculate the number of turns by using the 
following procedure:

 

(a)       The inductance factor (A

L

 in nH/T

2

) for the core 

is obtained from the core data sheet.  Determine 
the minimum A

L 

by using the worst case negative 

tolerance (generally -8%).  With this information, 
calculate the number of turns needed to obtain 
the required inductance from:

 

       Where L is required inductance (µH)

 

(b)     Calculate the bias in A·T/cm from:

 

    

 

(c)      From the Permeability vs. DC Bias curves (pages 

3-18 through 3-20 & 4-39 through 4-41), deter-
mine the rolloff in per unit of initial permeability 
for the previously calculated bias level.  Curve fit 
equations shown in the catalog can simplify this 
step. 

 

(d)      Multiply the required inductance by the per unit 

rolloff to find the inductance with bias current 
applied.

 

(e)  Increase the number of turns by dividing the initial 

number of turns (from step 4(a)) by the per unit 
initial value of permeability.  This will yield an induc-
tance close to the required value after steps 4 (b), 
(c) and (d) are repeated.

 

(f)   Iterate steps 4 (b), (c) and (d) if needed to adjust 

biased inductance up or down until it is satisfacto-
rily close to the target.

5.   Choose the correct wire size using the Wire Table 

(page 3-28).  Duty cycles below 100% allow smaller 
wire sizes and lower winding factors, but do not allow 
smaller core sizes.

6.   To calculate winding factor, multiply the number of 

turns by the wire area found on page 3-28 to find the 
total wire area. Divide the total wire area by the core 
window area to obtain the winding factor of the design. 
Verify that the winding factor is acceptable by referenc-
ing the various winding approaches described on page 
2-7.

7. 

 

If a significant ripple current will be present, estimate 
the core losses using the Core Loss Calculation pro-
cedure on pages 2-8 through 2-13.  If AC core losses 
will result in too much heating, or efficiency below 
requirements, then the inductor may be loss-limited 
rather than saturation-limited.  Design options for this 
core are to consider a larger core, a lower permeability 
material, a lower loss material or some combination of 
these three.

Inductor Core  

Selection Procedure

 2-2

www.mag-inc.com

Cor
e Selection

Core Selection Example

The core selector charts are a quick guide to finding the 
optimum permeability and smallest core size for DC bias 
applications.  These charts are based on a permeability 
reduction of not more than 50% with DC bias, typical winding 
factors of 40% for toroids and 60% for shapes, and an AC 
current that is small relative to the DC current.  These charts 
are based on the nominal core inductance and a current 
density 500-600 A/cm

2

.

If a core is being selected for use with a large AC current 
relative to any DC current, such as a flyback inductor or 
buck/boost inductor, frequently a larger core will be needed 
to limit the core losses due to AC flux. In other words, the 
design becomes loss-limited rather than bias-limited.

For additional power handling capability, stacking of cores will 
yield a proportional increase in power handling. For example, 
double stacking of the 55908 core will result doubled power 
handling capability to about 400 mH·A

2

.

Cores with increased heights are easily ordered. Contact 
Magnetics for more information.

Core Selector Charts

Determine core size and number of turns to meet the following 
requirement:

(a)    Minimum inductance with DC bias of 0.6 mH (600 uH)
(b)   DC current of 5.0 A

 
1.     LI

2

= 0.6 X 5.0

2

=15.0 mH·A

2

 
2.      Using the Kool Mµ LI

2

 chart found on page 2-4, locate 

15 mH·A

2

 on the bottom axis. Following this coordinate 

vertically results in the selection of 0077083A7 as an 
appropriate core for the above requirements.

 
3.      From the 0077083A7 core data page (4-23), the 

inductance factor (A

L

) of this core is 81 nH/T

2

 

±

 

8%. The 

minimum A

L

 of this core is 74.6 nH/T

2

.  

 
4.      The number of turns needed to obtain 600 µH at no load 

is 90 turns. To calculate the number of turns required at full 
load, determine the DC Bias level:  H= N·I/l

e

= A·T/cm where 

l

e

 is the path length in cm. The DC bias is 45.7 A·T/cm, 

yielding 69% of initial permeability.  
The adjusted turns are       =131 Turns.

5.      Re-calculate the DC bias level in A·T/cm: The permeability 

versus DC bias curve shows 54% of initial permeability at 
66.6 A·T/cm.

 
6.      Multiply the minimum A

L

 74.6 nH/T

2

 by 0.54 to yield 

effective A

L

 = 40.3 nH/T

2

. The inductance of this core with 

131 turns and with 66.6 A·T/cm will be 691 µH minimum. 
The minimum inductance requirement of 600 µH has been 
achieved with full DC bias.

 
7.      The wire table indicates that 17 AWG is needed to carry 

5.0 A with a current carrying capacity of 500 A/cm

2

. 

131 turns of 17 AWG (wire area = 1.177 mm

2

) equals 

a total wire area of 154.2 mm

2

. The window area of a 

0077083A7 is 427 mm

2

. Calculating window fill, 154.2 

mm

2

/427 mm

2

 corresponds to an approximate 36% 

winding factor. A 0077083A7 with 131 turns of 17 AWG 
will meet the all requirements for this inductor.

90

0.69

Cor

e Selection

2-3

MAGNETICS

Core Selector Charts

High Flux Toroids

MPP Toroids

0.0001

0.001

0.01

0.1

1

10

100

1000

LI², (mH·A²)

55135, pg 4-1 

55175, pg 4-3

55235, pg 4-5

55025, pg 4-8

55275, pg 4-9

55035, pg 4-11

55047, pg 4-13

55377, pg 4-15

55310, pg 4-17

55930, pg 4-19

55586, pg 4-21

55083, pg 4-23

55090, pg 4-25

55192, pg 4-27

55617, pg 4-29

55908, pg 4-32

55102, pg 4-33

55164, pg 4-35

55145, pg 4-2 

55015, pg 4-4

55265, pg 4-6

55405, pg 4-7

55285, pg 4-10

55125, pg 4-12

55117, pg 4-14

55206, pg 4-16

55350, pg 4-18

55071, pg 4-20

55076, pg 4-22

55439, pg 4-24

55716, pg 4-26

55111, pg 4-28

55868, pg 4-31

55735, pg 4-30

55336, pg 4-34

300µ

200µ

125µ

26µ

60µ

14µ

125  perm
90

100

75

60

40

50

26

25

160

147

14

173

200

250

300

550

500

0.001

0.01

0.1

1

10

100

1000

10000

LI², (mH·A²)

58165, pg 4-35

58737, pg 4-30

58907, pg 4-32

58617, pg 4-29

58195, pg 4-27

58438, pg 4-24

58254, pg 4-23

58548, pg 4-20

58929, pg 4-19

58309, pg 4-17

58118, pg 4-14

58048, pg 4-13

58038, pg 4-11

58278, pg 4-9

58028, pg 4-8

58238, pg 4-5

58337, pg 4-34

58099, pg 4-33

58867, pg 4-31

58110, pg 4-28

58716, pg 4-26

58090, pg 4-25

58324, pg 4-22

58585, pg 4-21

58349, pg 4-18

58204, pg 4-16

58378, pg 4-15

58128, pg 4-12

58288, pg 4-10

58408, pg 4-7

58268, pg 4-6

58018, pg 4-4

160µ

147µ

125µ

60µ

26µ

125  perm
90

100

75

60

40

50

26

25

160

147

14

173

200

250

300

550

500

 2-4

www.mag-inc.com

Cor
e Selection

Core Selector Charts

Kool Mµ

® 

E Cores

Kool Mµ

® 

Toroids & Race Tracks

0.0001

0.001

0.01

0.1

1

10

100

1000

LI², (mH·A²)

125µ

90µ

60µ

40µ

26µ

133RT026, pg 4-39
102RT026, pg 4-39
77735, pg 4-30
77868, pg 4-31

77212, pg 4-28

77721, pg 4-26
77095, pg 4-25
77076, pg 4-22
77586, pg 4-21
77354, pg 4-18
77210, pg 4-16

77380, pg 4-15
77130, pg 4-12

77290, pg 4-10
77410, pg 4-7
77270, pg 4-6
77020, pg 4-4
77150, pg 4-2

77165, pg 4-35

77337, pg 4-34

77102, pg 4-33
77908, pg 4-32
77616, pg 4-29
77192, pg 4-27
77439, pg 4-24

77083, pg 4-23
77071, pg 4-20

77934, pg 4-19
77314, pg 4-17
77120, pg 4-14

77050, pg 4-13

77040, pg 4-11
77280, pg 4-9

77030, pg 4-8

77240, pg 4-5
77180, pg 4-3
77140, pg 4-1

125  perm
90

100

75

60

40

50

26

25

160

147

14

173

200

250

300

550

500

LI², (mH·A²)

0.1

1

10

100

1000

K160LE026, pg 4-36

K8044E026, pg 4-36

K6527E040, pg 4-36

K5530E060, pg 4-36

K4022E090, pg 4-36

K4020E060, pg 4-36

K3515E090, pg 4-36

K2510E090, pg 4-36

K130LE026, pg 4-36

K8020E040, pg 4-36

K7228E040, pg4-36

K5528E060, pg 4-36

K4017E060, pg 4-36

K4317E090, pg 4-36

K3007E090, pg 4-36

K1808E090, pg 4-36

26µ

90µ

60µ

40µ

125  perm
90

100

75

60

40

50

26

25

160

147

14

173

200

250

300

550

500

Cor

e Selection

2-5

MAGNETICS

Core Selector Charts

XF

LUX

® 

 Toroids

Kool Mµ

® 

U Cores

78907, pg 4-32

78110, pg 4-28

78716, pg 4-26

78439, pg 4-24

78076, pg 4-22

78071, pg 4-20

78351, pg 4-18

78848, pg 4-16

78381, pg 4-15

78867, pg 4-31

78192, pg 4-27

78090, pg 4-25

78083, pg 4-23

78586, pg 4-21

78894, pg 4-19

78059, pg 4-17

78121, pg 4-14

78051, pg 4-13

LI², (mH·A²)

0.1

1

10

100

60µ

125  perm
90

100

75

60

40

50

26

25

160

147

14

173

200

250

300

550

500

LI², (mH·A²)

1

10

100

1000

26µ

90µ

K8020U026, pg 4-38

K7236U026, pg 4-38

K5529U026, pg 4-38

K4119U090, pg 4-38

K4110U090, pg 4-38

K8038U026, pg 4-38

K6527U026, pg 4-38

K6533U026, pg 4-38

K5527U026, pg 4-38

K4111U090, pg 4-38

K3112U090, pg 4-38

125  perm
90

100

75

60

40

50

26

25

160

147

14

173

200

250

300

550

500

 2-6

www.mag-inc.com

Cor
e Selection

Designing With Magnetics 

Powder Cores

Winding Factor

Winding factor, also called fill factor, is the ratio of total 

conductor cross section (usually copper cross section) to the 

area of the core window.  In other words, in a toroid, winding 

factor is given by:

 

 

  

 

N·A

w 

/ W

A

 

 

 

N = Number of turns

where:  

A

w

 = Area of the wire 

 

 

W

A

 = Window Area of the core 

p

 ·ID

2

Toroid Core Winding factors can vary from 20-60%, a typical 

value in many applications being 35-40%.

In practice, several approaches to toroid winding are used:

Single layer: 

-­‐   



The number of turns is limited by the 

inside circumference of the core divided by the wire 

diameter.  Advantages are lower winding capacitance, 

more repeatable parasitics, good cooling, and low 

cost.  Disadvantages are reduced power handling and 

higher flux leakage. 

Low fill:

-­‐   



 For manufacturing ease and reduced 

capacitance, winding factor between single layer and 

30% may be used. 

Full winding:

-­‐   



 factors between 30% and 45% are 

normally a reasonable trade off between fully utilizing 

the space available for a given core size, while 

avoiding excessive manufacturing cost. 

High fill: 

-­‐   



Winding factors up to about 65% are 

achievable, but generally only with special expensive 

measures, such as completing each coil by hand after 

the residual hole becomes too small to fit the winding 

shuttle.

Mean Length of Turn

Winding turn lengths have been computed for each core size, 

using empirical relationships, for ten winding factors.  This 

permits an estimate of actual length/turn for any winding factor.

MLT (Mean Length Turn) DCR Calculation 

Calculating nominal DC Resistance for a single layer winding 

is straightforward.  The mean length of turn (MLT) is simply the 

length of any turn along the surface of the core.  MLT data can 

be found on each core data page. Then,

DCR = (MLT)(N) (

Ɵ

/length of wire)

Even easier, Magnetics has calculated the single layer DCR for a 

range of wire gauges for each core size.  See Winding Tables on 

pages 6-1 to 6-6.

Calculation Method

Calculate the winding factor for the core, wire gauge, and 

number of turns selected.  On the wire table look up resistance 

per unit of length for the gauge selected.

On the data page for the core selected, consult the Winding 

Turn Length chart.  Unless the winding factor is exactly one of 

the values listed, interpolate to find the MLT.

4

Wound Coil Dimensions

Wound coil dimensions are listed for 70% winding factor, as these 

are the largest dimensions necessary for packaging the wound 

coil.  These dimensions are attainable. As a 70% winding factor 

(no residual hole) yields the same overall coil dimensions as a 

100% (unity) winding factor (no interstices).  Coil dimensions for 

coils wound to 40% winding factor can be estimated as follows.

 

 

OD

40%

 = 0.5(OD

core

 + OD

70%

)

where:  

OD

core 

= core OD after finish

 

 

OD

70% 

= wound coil OD

HT

40%

 = 0.45(HT

core

 + HT

70%

)

where:  

HT

core 

= core OD after finish

 

 

HT

70% 

= wound coil OD

For other winding factors, OD dimension can be approximated by:

where:  

 r

x

=radius at unique winding factor

 

 

x=winding factor

 

 

OD

x

=2r

x

Heat to be dissipated in a magnetic component arises from 

energy losses due to DC resistance in the coil (I

2

R); AC copper 

losses, if high frequency AC current is present; and AC core 

losses, if AC current is present.  (DC current does not result in 

any core losses, regardless of the magnitude.)  Heat dissipa-

tion and temperature rise (

∆

T) depend on many factors, so 

there is no simple way to predict 

∆

T precisely.  But the follow-

ing formula is useful for approximating 

∆

T for a component in 

still air.

Surface Area is that of the wound component.  In this catalog, 

surface area is presented in two ways:

Unwound, coated core

1.   



Wound core, assuming 40% winding factor

2.   



Temperature Rise Calculation

Cor

e Selection

2-7

MAGNETICS

Designing With Magnetics 

Powder Cores

 2-8

www.mag-inc.com

Cor
e Selection

Powder Core Loss Calculation

Magnetizing Force, H(A·T/cm)

1

10

100

800

0.6
0.5

0.3

0.1

0.4

0.2

0

0.8
0.7

1

1.1

0.9

Flux Density

, (Tesla)

100  perm
50
20
10
5
2
1
100
60

H

AC min

H

AC max

B

AC max

B

AC min

B

Core loss is generated by changing magnetic flux field within a material, since no magnetic materials exhibit perfectly efficient 

magnetic response.  Core loss density (PL) is a function of half of the AC flux swing (½     B

I

B

pk

) and frequency 

(f)

. It can be 

approximated from core loss charts or the curve fit loss equation:

where a, b, c are constants determined from curve fitting, and B

pk

 is defined as half of the AC flux swing:

Units typically used are (mW/cm

3

) for PL; Tesla(T) for B

pk

; and (kHz) for 

f

.

The task of core loss calculation is to determine B

pk

 from known design parameters. 

Method 1 – Determine B

pk

 from DC Magnetization Curve. B

pk

= 

f(H)

Flux density (B) is a non-linear function of magnetizing field (H), which in turn is a function of winding number of turns (N), current (I), and 

magnetic path length (

l

e

). The value of B

pk

 can typically be determined by first calculating 

H

 at each AC extreme:

Units typically used are (A·T/cm) for H. 

From H

AC max

, H

AC min

, and the BH curve (or BH curve fit equation), B

AC max

, B

AC min

 and therefore B

pk

 can be determined.

Cor

e Selection

2-9

MAGNETICS

Powder Core Loss Calculation

Example 1 – AC current is 10% of DC current:

Approximate the core loss of an inductor with 20 turns wound on Kool Mµ p/n 77894A7 (60µ, l

e

=6.35cm, A

e

=0.654cm

2

, A

L

=75nH/T

2

). 

Inductor current is 20 Amps DC with ripple of 2 Amps peak-peak at 100kHz.

1.) Calculate 

H

 and determine 

B

 from BH curve or curve fit equation:

 

2.) Determine Core Loss density from chart or calculate from loss equation:

3.) Calculate core loss:

Example 2 – AC current is 40% of DC current:

Approximate the core loss for the same 20-turn inductor, with same inductor current of 20 Amps DC but ripple of 8 Amps peak-

peak at 100kHz.

1.) Calculate 

H

 and determine 

B

 from BH curve:

2.) Determine Core Loss density from chart or calculate from loss equation: 

3.) Calculate core loss:

 2-10

www.mag-inc.com

Cor
e Selection

Powder Core Loss Calculation

Magnetizing Force, H (A·T/cm)

60

µ

 Kool M

µ

 DC Magnetization Curve

0

20

40

60

80

100

-20

0.3

0.2

0.1

0

-0.1

-0.2

0.4

0.5

0.6

Flux Density

, (Tesla)

100  perm
50
20
10
5
2
1
100
60

Example 1

H

AC max

=66.14

B

AC max

=0.44

Example 2

H

AC min

=50.39

B

AC min

=0.36

Example 3
H

AC min

= -12.6

B

AC min

= -0.11

Example 3
H

AC max

=12.6

B

AC max

=0.11

Example 1

H

AC min

=59.84

B

AC min

=0.41

Example 2

H

AC max

=75.59

B

AC max

=0.48

H

DC

=63

Example 1&2

H

DC

=0

Example 3

Example 3 – pure AC, no DC:

Approximate the core loss for the same 20-turn inductor, now with 0 Amps DC and 8 Amps peak-peak at 100kHz.

1.) Calculate 

H

 and determine 

B

 from BH curve:

2.) Determine Core Loss density from chart or calculate from loss equation: 

3.) Calculate core loss:

Note the significant influence of DC bias on core loss, comparing Example 3 with Example 2. Lower permeability results in less B

pk

, 

even if the current ripple is the same. This effect can be achieved with DC bias, or by selecting a lower permeability material.

Where AC is small, the following methods (2 and 3) can be used to approximate B

pk

.

2-11

MAGNETICS

Cor

e Selection

Powder Core Loss Calculation

where

Method 2, Determine B

pk

 from effective perm at DC bias. B

pk 

= 

f

(µ

e

,     H)

The instantaneous slope of the BH curve is defined as the absolute permeability, which is the product of permeability of free space 

(µ

0

=4

p

 x10

-7

) and the material permeability (µ), which varies along the BH curve. For small AC, this slope can be modeled as a constant 

throughout AC excitation, with µ approximating the effective perm at DC bias (µ

e

):

The effective perm with DC bias is more commonly written in terms of % of initial perm and can be obtained from the DC bias curve or 
curve fit equation:

Reworking Example 1 (20 Amps DC, 2 Amps p-p)

Reworking Example 2 (20 Amps DC, 8 Amps p-p) 

 

From example 1,

Reworking Example 3 (0 Amps DC, 8 Amps p-p) 

 

From example 2,

 2-12

www.mag-inc.com

Cor
e Selection

Powder Core Loss Calculation

Method 3, Determine B

pk

 from biased inductance. B

pk=

=

f

(L,I)

B can be rewritten in terms of inductance by considering Faraday’s equation and its effect on inductor current:

Where L varies non-linearly with H. For small AC, the slope of the BH curve is assumed constant throughout AC excitation, and L 

approximates the biased inductance (L

DC

).

Substituting (dH/dI)  with (N/l

e

)  and A with A

e

:

Another way of looking at this is by rewriting the relationship between B and L as:

Where L varies non-linearly with I. For small AC, L is assumed constant throughout AC excitation and approximates biased 

inductance (L

DC

).

Cor

e Selection

2-13

MAGNETICS

Powder Core Loss Calculation

Magnetizing Force, H(A·T/cm)

45

55

60

65

50

70

75

80

0.42

0.38

0.36

0.4

0.34

0.44

0.5

0.48

0.46

Flux Density

, (Tesla)

100  perm
50
20
10
5
2
1
100
60

DC Bias

B

Method 1

Example 2

Method 2

Example 2

REF only. µ

e

 is best 

approximated from 

DC Bias curve.

Example 1

Example 2

B

Reworking Example 1:

Reworking Example 2:

Reworking Example 3:

60µ Kool Mµ DC Magnetization Curve

Technical Data

www.mag-inc.com

 3-1

Material Properties

PERMEABILITY VS. T, B, & f - TYPICAL

Permeability (µ)

µ vs. T dynamic range 

(-50º C TO +100º C)

MATERIALS RATED TO 200º C

µ vs. B dynamic range 

0 to 400 mT

µ vs.f. 

flat to...

MPP

14µ

0.7%

+0.4%

4 MHz

26µ

0.9%

+0.4%

3 MHz

60µ

1.0%

+0.8%

2 MHz

125µ

1.3% 

+1.4%

300 kHz

147µ, 160µ, 173µ

1.5%

+1.9%

200 kHz

200µ

1.6%

+2.8%

100 kHz

300µ

1.6%

+4.5%

90 kHz

550µ

8.7%

+21.0%

20 kHz

High Flux

14µ

1.5%

+5.0%

3 MHz

26µ

2.0%

+9.0%

1.5 MHz

60µ

2.6%

+13.5%

1 MHz

125µ

3.6%

+19.0%

700 kHz

147µ

4.8%

+22.0%

500 kHz

160µ

5.5%

+25.0%

400 kHz

Kool Mµ

®

26µ

1.7%

+1.0%

2 MHz

40µ

2.2%

+1.1%

1 MHz

60µ

3.4%

+1.4%

900 kHz

75µ

4.5%

+2.0%

500 kHz

90µ

5.2%

+2.8%

500 kHz

125µ

8.3%

+3.4%

300 kHz

X

F

LUX

®

60µ

3.0%

+14.5%

500 kHz

Curie 

Temperature

Density

Coefficient of  

Thermal Expansion

MPP

460

°

C

8.0 grams/cm

3

12.9 x 10

-6

/

°

C

High Flux

500

°

C

7.6 grams/cm

3

5.8 x 10

-6

/

°

C

 Kool Mµ

500

°

C

5.5 grams/cm

3

10.8 x 10

-6

/

°

C

X

F

LUX

700

°

C

7.5 grams/cm

3

11.6 x 10

-6

/

°

C

Technical Data

3-2

MAGNETICS

Conversion Tables

To obtain number of

Multiply number of

By

A·T/cm

oersteds

0.795

oersteds

A·T/cm

1.26

tesla

gauss

0.0001

cm

2

in

2

6.452

cm

2

circular mils

5.07 x 10

-6

Gauss

mT(milli Tesla)

10

Gauss

Tesla

10,000

Permeability

14µ

26µ

40µ

60µ

75µ

90µ

125µ

147µ 

160µ 

173µ

200µ 

300µ

550µ

x Factor

0.80

0.86

0.90

0.94

0.96

0.97

1.00

1.02

1.03

1.04

Core weights listed in this catalog are for 125µ cores.*  
To determine weights for other permeabilities, multiply the 125µ weight by the following factors:

*XF

LUX

®

 

is based on 60 perm weight.

*MPP, High Flux, and Kool Mµ

®

 in sizes 102, 337, and 165 weight based on 26µ.

Technical Data

 3-3

www.mag-inc.com

Normal Magnetization Curves

MPP

High Flux

Magnetizing Force (A·T/cm)

1

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

10

100

800

Flux Density (T

esla)

125  perm

90

75

60

40

26

160

147

14

173

200

250

300

550

500

550µ

300µ

200µ

60µ

26µ

14µ

173µ

160µ

147µ

125µ

Magnetizing Force (A·T/cm)

1

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

1.5

10

100

800

Flux Density (T

esla)

125  perm

90

75

60

40

26

160

147

14

173

200

250

300

550

160µ

147µ,

125µ

60µ

26µ

14µ

Technical Data

3-4

MAGNETICS

Normal Magnetization Curves

Kool Mµ

®

X

F

LUX

®

Magnetizing Force (A·T/cm)

1

0

0.2

0.1

0.3

0.5

0.7

0.9

1.1

0.4

0.6

0.8

1.0

10

100

800

Flux Density (T

esla)

125  perm

90

75

60

40

26

160

147

14

173

200

250

300

550

125µ

90µ

75µ

60µ

40µ

26µ

Magnetizing Force (A·T/cm)

1

0

0.2

0.4

0.6

0.8

1.0

1.2

1.6

1.4

10

100

800

Flux Density (T

es

la)

125  perm

90

75

60

40

26

160

147

14

173

200

250

300

550

500

60µ

Technical Data

 3-5

www.mag-inc.com

Normal Magnetization Curve

a

b

c

d

e

x

MPP

14µ

-7.507E+00

6.573E+00

4.619E-01

7.777E+01

4.987E-01

2

26µ

6.679E-02

1.105E-02

-1.136E-05

1.112E-02

-1.233E-05

2

60µ

8.146E-02

2.345E-02

6.032E-05

2.476E-02

7.185E-05

2

125µ

6.420E-04

-6.271E-04

3.253E-04

9.901E-03

5.366E-04

0.5

147µ

6.530E-04

-7.301E-04

4.516E-04

1.583E-02

7.185E-04

0.5

160µ

4.470E-04

-5.579E-04

5.211E-04

1.002E-02

8.164E-04

0.5

173µ

5.450E-04

-7.716E-04

6.506E-04

6.875E-03

1.019E-03

0.5

200µ

1.001E-03

-1.450E-03

9.127E-04

6.057E-03

1.428E-03

0.5

300µ

9.400E-04

-1.543E-03

1.990E-03

2.400E-02

3.073E-03

0.5

550µ

7.300E-04

-1.509E-03

6.482E-03

6.371E-02

9.933E-03

0.5

High 

Flux

14µ

-5.945E-02

8.703E-03

3.623E-04

5.290E-02

3.474E-04

2

26µ

-4.067E-02

1.637E-02

3.742E-04

5.316E-02

3.413E-04

2

60µ

-1.695E-01

1.215E-01

1.213E-02

6.938E-01

1.016E-02

2

125µ

5.320E-04

-6.811E-04

3.506E-04

1.052E-02

1.694E-04

0.5

147µ

2.670E-04

-7.829E-04

5.290E-04

2.215E-03

2.606E-04

0.5

160µ

2.670E-04

-7.829E-04

5.290E-04

2.215E-03

2.606E-04

0.5

Kool 

Mµ

®

26µ

5.868E-05

9.362E-05

9.011E-06

-3.682E-04

8.747E-06

0.5

40µ

8.870E-05

5.592E-05

2.700E-05

2.928E-04

2.574E-05

0.5

60µ

1.658E-04

2.301E-05

7.297E-05

5.906E-03

6.053E-05

0.5

75µ

1.433E-05

9.724E-05

1.323E-04

7.255E-03

1.131E-04

0.5

90µ

5.660E-04

-1.216E-04

1.974E-04

7.278E-03

1.698E-04

0.5

125µ

7.808E-05

5.088E-04

2.595E-04

3.922E-03

2.285E-04

0.5

X

F

LUX

®

60µ

-1.695E-01

1.315E-01

1.220E-02

7.434E-01

8.891E-03

2

where:

1 + dH + eH

2

a + bH + cH

2

X

B =

Fit Formula 

(refer to curves for units)

Technical Data

3-6

MAGNETICS

Core Loss Density Curves

MPP 14µ

High Flux 14µ

Flux Density (Tesla)

0.01

0.1

0.7

1

0.1

0.01

10

100

1000

10000

Core Loss (mW/cm

3

)

300  khz
100  khz
50  khz

20  khz

25  khz

10  khz
5  khz  
2  khz
100  hz  
60  hz
500  hz

P

L 

= 115.9B

2.5

F

1.87

300 kHz

100 kHz

50 kHz

20 kHz

10 kHz

5 kHz

2 kHz

Flux Density (

Tesla

)

0.01

0.1

1

1

0.1

10

100

1000

3000

Core Loss (mW/

cm

3

)

P

L 

= 388.8B

2.31

F

1.54

100 kHz

50 kHz

20 kHz

10 kHz

5 kHz

2 kHz

1 kHz

100 Hz

60 Hz

300  khz
100  khz
50  khz

20  khz

25  khz

10  khz
5  khz  
2  khz
1  khz
100  hz  
60  hz
500  hz

Technical Data

 3-7

www.mag-inc.com

Core Loss Density Curves

MPP 26µ

High Flux 26µ

Flux Density (Tesla)

0.01

0.1

0.7

1

0.1

10

100

1000

10000

Core Loss (mW/cm

3

)

300  perm
100
50
20
10
5
2

P

L 

= 70.83B

2.34

F

1.65

300 kHz

100 kHz

50 kHz

20 kHz

10 kHz

5 kHz

300  khz
100  khz
50  khz

20  khz

25  khz

10  khz
5  khz  
2  khz
100  hz  
60  hz
500  hz

Flux Density (Tesla)

0.01

0.1

1

1

0.1

10

100

1000

3000

Core Loss (mW/cm

3

)

P

L 

= 374.9B

2.21

F

1.49

100 kHz

50 kHz

20 kHz

10 kHz

5 kHz

2 kHz

1 kHz

100 Hz

60 Hz

300  khz
100  khz
50  khz

20  khz

25  khz

10  khz
5  khz  
2  khz
1  khz
100  hz  
60  hz
500  hz

Technical Data

3-8

MAGNETICS

Core Loss Density Curves

MPP 60µ

High Flux 60µ

Flux Density (Tesla)

0.01

0.1

0.7

1

10

100

1000

10000

Core Loss (mW/cm

3

)

P

L 

= 357.1B

2.05

F

1.12

300 kHz

100 kHz

50 kHz

20 kHz

10 kHz

5 kHz

300  khz
100  khz
50  khz

20  khz

25  khz

10  khz
5  khz  
2  khz
1  khz
100  hz  
60  hz
500  hz

Flux Density (Tesla)

0.01

0.1

1

1

0.1

10

100

1000

Core Loss (mW/cm

3

)

P

L 

= 492B

2.22

F

1.32

100 kHz

50 kHz

20 kHz

10 kHz

5 kHz

2 kHz

1 kHz

100 Hz

60 Hz

300  khz
100  khz
50  khz

20  khz

25  khz

10  khz
5  khz  
2  khz
1  khz
100  hz  
60  hz
500  hz

Technical Data

 3-9

www.mag-inc.com

Core Loss Density Curves

MPP 125µ

High Flux 125µ

Flux Density (Tesla)

0.1

0.01

1

0.1

0.01

1

10

100

1000

10000

Core Loss (mW/cm

3

)

300  khz
100  khz
50  khz

20  khz

25  khz

10  khz
5  khz  
2  khz
1  khz
100  hz  
60  hz
500  hz

P

L 

= 53.05B

2.06

F

1.56

300 kHz

100 kHz

25 kHz

50 kHz

10 kHz

5 kHz

2 kHz

1 kHz

500 Hz

Flux Density (Tesla)

0.01

0.1

1

1

0.1

10

100

1000

3000

Core Loss (mW/cm

3

)

P

L 

= 246B

2.23

F

1.47

100 kHz

50 kHz

20 kHz

10 kHz

5 kHz

2 kHz

1 kHz

100 Hz

60 Hz

300  khz
100  khz
50  khz

20  khz

25  khz

10  khz
5  khz  
2  khz
1  khz
100  hz  
60  hz
500  hz

Technical Data

3-10

MAGNETICS

Core Loss Density Curves

MPP 147µ, 160µ, 173µ

High Flux 147µ, 160µ

Flux Density (Tesla)

0.1

0.7

0.1

0.01

0.01

1

10

100

1000

10000

Core Loss (mW/cm

3

)

P

L 

= 52.16B

2

F

1.57

300 kHz

100 kHz

50 kHz

25 kHz

10 kHz

5 kHz

2 kHz

1 kHz

500 Hz

300  khz
100  khz
50  khz

20  khz

25  khz

10  khz
5  khz  
2  khz
1  khz
100  hz  
60  hz
500  hz

Flux Density (Tesla)

0.01

0.1

1

1

0.1

10

100

1000

Core Loss (mW/cm

3

)

P

L 

= 447.6B

2.3

F

1.41

100 kHz

50 kHz

20 kHz

10 kHz

5 kHz

2 kHz

1 kHz

100 Hz

100  perm
50
20
10
5
2
1
100
60

300  khz

500  khz

100  khz
50  khz

20  khz

25  khz

10  khz
5  khz  
2  khz
1  khz
100  hz  
60  hz
500  hz

200  khz

Technical Data

 3-11

www.mag-inc.com

Core Loss Density Curves

Flux Density (Tesla)

0.1

0.7

0.1

0.01

0.01

1

10

100

1000

10000

Core Loss (mW/cm

³)

P

L 

= 37.97B

2.09

F

1.68

300 kHz

100 kHz

50 kHz

25 kHz

10 kHz

5 kHz

2 kHz

1 kHz

500 Hz

300  khz
100  khz
50  khz

20  khz

25  khz

10  khz
5  khz  
2  khz
1  khz
100  hz  
60  hz
500  hz

MPP 200µ, 300µ

MPP 550µ

Flux Density (Tesla)

0.01

0.7

0.1

0.1

0.01

1

10

100

1000

10000

Core Loss (mW/cm

3

)

300  khz

500  khz

100  khz
50  khz

20  khz

25  khz

10  khz
5  khz  
2  khz
1  khz
100  hz  
60  hz
500  hz

200  khz

P

L 

= 181B

2.13

F

1.47

300 kHz

100 kHz

50 kHz

25 kHz

10 kHz

5 kHz

2 kHz

1 kHz

500 Hz

Technical Data

3-12

MAGNETICS

Core Loss Density Curves

Kool Mµ

® 

26µ, 40µ

Kool Mµ

® 

60µ, 75µ, 90µ

Flux Density (Tesla)

0.01

0.1

1

10

1

100

1000

10000

Core Loss (mW/cm

3

)

100 kHz

200 kHz

50 kHz

25 kHz

P

L 

= 120B

2.09

F

1.46

300  khz

100  khz

200  khz

50  khz

20  khz

25  khz

10  khz
5  khz  
2  khz
1  khz
100  hz  
60  hz
500  hz

Flux Density (Tesla)

0.01

0.1

1

10

1

100

1000

10000

Core Loss (mW/cm

3

)

500 kHz

300 kHz

200 kHz

100 kHz

50 kHz

25 kHz

P

L 

= 193B

2.01

F

1.29

300  khz

500  khz

100  khz
50  khz

20  khz

25  khz

10  khz
5  khz  
2  khz
1  khz
100  hz  
60  hz
500  hz

200  khz