IEC 60938-1:2021

Fixed inductors for electromagnetic interference suppression - Part 1: Generic specification

IEC 60938-1:2021 applies to inductors designed for electromagnetic interference suppression intended for use within all kind of electric and electronic equipment.
In this generic specification, normative references and terms and definitions are given. It also prescribes general requirements and the suitable test and measurement procedures for interference suppression inductors. Annex B states special requirements for earth inductors.
This edition includes the following significant technical changes with respect to the previous edition:
a) material tests added;
b) improved readability and clear separation between test descriptions in the generic spec and requirements in the sectional specification;
c) creepage and clearance requirements are now defined in sectional specifications only;
d) AC testing for voltage test included.

Inductances fixes d’antiparasitage - Partie 1: Spécification générique

L’IEC 60938-1:2021 s'applique à des inductances conçues pour l’antiparasitage et destinées à être utilisées dans tous les types d’équipements électriques et électroniques.
La présente spécification générique comporte des références normatives ainsi que des termes et définitions. Elle spécifie également les exigences générales et les modes opératoires d’essai et de mesure appropriés pour les inductances d’antiparasitage. L’Annexe B précise les exigences particulières applicables aux inductances de terre.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) ajout d’essais de matériaux;
b) amélioration de la lisibilité et séparation claire entre les descriptions des essais dans la spécification générique et les exigences dans la spécification intermédiaire;
c) les exigences de ligne de fuite et de distance d’isolement sont désormais définies uniquement dans les spécifications intermédiaires;
d) Les essais de tension en courant alternatif sont inclus.

General Information

• Status: Published
• Publication Date: 15-Jun-2021
• ICS: 29.100.10 - Magnetic components
• ICS: 31.020 - Electronic components in general
• Technical Committee: TC 40 - Capacitors and resistors for electronic equipment
• Current Stage: PPUB - Publication issued
• Completion Date: 16-Jun-2021

Standards Content (sample)

IEC 60938-1
Edition 3.0 2021-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Fixed inductors for electromagnetic interference suppression –
Part 1: Generic specification
Inductances fixes d’antiparasitage –
Partie 1: Spécification générique
IEC 60938-1:2021-06(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 60938-1
Edition 3.0 2021-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Fixed inductors for electromagnetic interference suppression –
Part 1: Generic specification
Inductances fixes d’antiparasitage –
Partie 1: Spécification générique
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.100.10; 31.020 ISBN 978-2-8322-9883-1

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – IEC 60938-1:2021 © IEC 2021
CONTENTS

FOREWORD ........................................................................................................................... 4

INTRODUCTION ..................................................................................................................... 6

1 Scope .............................................................................................................................. 8

2 Normative references ...................................................................................................... 8

3 Terms, definitions and conventions .................................................................................. 9

3.1 Terms and definitions .............................................................................................. 9

3.2 Conventions .......................................................................................................... 11

4 General requirements .................................................................................................... 11

4.1 General ................................................................................................................. 11

4.2 Preferred values ................................................................................................... 12

4.2.1 General ......................................................................................................... 12

4.2.2 Rated current ................................................................................................. 12

4.2.3 Temperature de-rated current ........................................................................ 12

4.3 Information to be given in a detail specification ..................................................... 12

4.3.1 General ......................................................................................................... 12

4.3.2 Outline drawing and dimensions .................................................................... 12

4.3.3 Mounting ....................................................................................................... 13

4.3.4 Ratings and characteristics ............................................................................ 13

4.4 Insulated inductors ................................................................................................ 13

4.5 Marking ................................................................................................................. 13

5 Tests and measurement procedures .............................................................................. 14

5.1 General ................................................................................................................. 14

5.2 Standard atmospheric conditions .......................................................................... 14

5.3 Visual examination ................................................................................................ 14

5.4 Insulation resistance ............................................................................................. 14

5.5 Voltage test .......................................................................................................... 15

5.6 Inductance ............................................................................................................ 16

5.7 Resistance ............................................................................................................ 16

5.8 Insertion loss ........................................................................................................ 16

5.9 Temperature rise .................................................................................................. 16

5.10 Impulse voltage..................................................................................................... 16

5.11 Endurance ............................................................................................................ 17

5.12 Robustness of terminations ................................................................................... 17

5.13 Vibration ............................................................................................................... 17

5.14 Shock ................................................................................................................... 17

5.15 Resistance to soldering heat ................................................................................. 18

5.16 Solderability .......................................................................................................... 20

5.16.1 General ......................................................................................................... 20

5.16.2 Preconditioning .............................................................................................. 20

5.16.3 Test procedure .............................................................................................. 21

5.16.4 Final inspection, measurements, and requirements........................................ 21

5.17 Rapid change of temperature ................................................................................ 21

5.18 Container sealing .................................................................................................. 21

5.19 Climatic sequence................................................................................................. 21

5.19.1 General ......................................................................................................... 21

5.19.2 Dry heat ........................................................................................................ 21

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IEC 60938-1:2021 © IEC 2021 – 3 –

5.19.3 Damp heat, cyclic, test Db, first cycle ............................................................ 22

5.19.4 Cold............................................................................................................... 22

5.19.5 Low air pressure ............................................................................................ 22

5.19.6 Damp heat, cyclic, test Db, remaining cycles ................................................. 22

5.20 Damp heat, steady state ....................................................................................... 23

5.21 Passive flammability ............................................................................................. 23

5.22 Glow wire .............................................................................................................. 23

5.23 Ball pressure......................................................................................................... 23

5.24 Component solvent resistance .............................................................................. 23

5.25 Solvent resistance of marking ............................................................................... 24

Annex A (normative) Measuring points for electrical tests and measurements ...................... 25

A.1 General ................................................................................................................. 25

A.2 Foil method ........................................................................................................... 25

A.3 Method for inductors with mounting devices .......................................................... 25

A.4 V-block method ..................................................................................................... 26

Annex B (normative) Requirements for earth inductors ........................................................ 27

Annex C (normative) Example of a suitable circuit for the voltage endurance test ................ 28

Annex X (informative) Cross-references to the previous edition of this document ................. 29

Bibliography .......................................................................................................................... 31

Figure 1 – Relevant specification ............................................................................................ 7

Figure 2 – Relation between ambient temperature and applied current ................................. 12

Figure 3 – Temperature profile for reflow simulation.............................................................. 19

Figure A.1 – Examples how to connect electrical tests .......................................................... 26

Figure C.1 – Test circuit for endurance voltage ..................................................................... 28

Table 1 – Standard atmospheric conditions ........................................................................... 14

Table 2 – Measuring voltage for insulation resistance testing ................................................ 15

Table 3 – Temperatures for reflow simulation with different solder paste alloy types ............. 20

Table 4 – Number of remaining cycles for damp heat ............................................................ 22

Table A.1 – Measuring points for electrical tests ................................................................... 25

Table B.1 – Minimum copper cross-sectional area of earth inductor’s winding ...................... 27

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– 4 – IEC 60938-1:2021 © IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FIXED INDUCTORS FOR ELECTROMAGNETIC
INTERFERENCE SUPPRESSION –
Part 1: Generic specification
FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international

co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and

in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,

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may participate in this preparatory work. International, governmental and non-governmental organizations liaising

with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for

Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.

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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

indispensable for the correct application of this publication.

9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent

rights. IEC shall not be held responsible for identifying any or all such patent rights.

IEC 60938-1 has been prepared by IEC technical committee 40: Capacitors and resistors for

electronic equipment. It is an International Standard.

This third edition cancels and replaces the second edition published in 1999. This edition

constitutes a technical revision.

This edition includes the following significant technical changes with respect to the previous

edition:
a) material tests added;

b) improved readability and clear separation between test descriptions in the generic spec and

requirements in the sectional specification;

c) creepage and clearance requirements are now defined in sectional specifications only;

d) AC testing for voltage test included.
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IEC 60938-1:2021 © IEC 2021 – 5 –
The text of this International Standard is based on the following documents:
FDIS Report on voting
40/2834/FDIS 40/2851/RVD

Full information on the voting for its approval can be found in the report on voting indicated in

the above table.
The language used for the development of this International Standard is English.

A list of all parts in the IEC 60938 series, published under the general title Fixed inductors for

electromagnetic interference suppression, can be found on the IEC website.

This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in

accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available

at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are

described in greater detail at www.iec.ch/standardsdev/publications.

The committee has decided that the contents of this document will remain unchanged until the

stability date indicated on the IEC website under webstore.iec.ch in the data related to the

specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
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– 6 – IEC 60938-1:2021 © IEC 2021
INTRODUCTION

The specification system for fixed inductors for electromagnetic interference suppression is

structured in a hierarchical system consisting of the following specification types.

Generic specification

The generic specification covers all subjects mainly common to the family of fixed inductors for

electromagnetic interference suppression, such as terminology, methods of measurement and

tests. Where the individual subjects require the prescription conditions or parameters specific

to the particular sub-family or type of inductor, such prescriptions are required to be given by

one of the subordinate specifications.

For the scope of fixed inductors, the numeric reference to the generic specification is

IEC 60938-1.
Sectional specification

Sectional specifications cover all subjects additional to those given in the generic specification,

which are specific to a defined sub-group of fixed inductors for electromagnetic interference

suppression. These subjects normally are preferred values for dimensions and characteristics,

relevant prescriptions for test methods given in the generic specification, prescriptions for

sampling and for the preparation of specimen, recommended test severities and preferred

acceptance criteria. The sectional specification also outlines the structure and scope of the test

schedules, which are to be applied in all subordinate detail specifications.

For the scope of fixed inductors for electromagnetic interference suppression, the numeric

reference to the only sectional specification is 60938-2 for line chokes.
Detail specification

Detail specifications give directly, or by making reference to other specifications, all information

necessary to completely describe a given type and range of fixed inductors for electromagnetic

interference suppression, including prescriptions of all values for dimensions and

characteristics. They also give all information required for all applied test severities and

acceptance criteria, and the completed test schedules.

Detail specifications can be either specifications within the IEC system, another specification

system linked to IEC, or specified by the manufacturer or user.
Blank detail specification

The hierarchical system of specifications can be supplemented by one or more blank detail

specifications to a sectional specification, which are used to ensure a uniform presentation of

detail specifications. The blank detail specifications provide the specification writer with a

template on the layout to be adopted and on the information to be given and with guidance for

the preparation of detail specifications in line with the requirements of the superior generic or

sectional specifications. Blank detail specifications are not considered to be relevant

specifications since they do not themselves describe any particular component.

The presence of an established hierarchical specification system with blank detail specifications

permits the preparation of detail specifications, even outside of the relevant IEC technical

committee.

For the scope of fixed inductors for electromagnetic interference suppression, the numeric

references to blank detail specifications are, for example, IEC 60938-2-1, if related to the

sectional specification IEC 60938-2.
---------------------- Page: 8 ----------------------
IEC 60938-1:2021 © IEC 2021 – 7 –
Relevant specification

In this system, the term "relevant specification" addresses subordinate specifications containing

specific requirements, where applicable (see Figure 1).

Any generic or sectional specification can use abstract and universal references to subordinate

specifications of either hierarchical level by use of the expression "relevant specification".

Key

1) Indicates the range of "relevant specifications" to the superior generic specification, where applicable.

2) Indicates the range of "relevant specifications" to the superior sectional specification, where applicable.

Figure 1 – Relevant specification
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– 8 – IEC 60938-1:2021 © IEC 2021
FIXED INDUCTORS FOR ELECTROMAGNETIC
INTERFERENCE SUPPRESSION –
Part 1: Generic specification
1 Scope

This part of IEC 60938 applies to inductors designed for electromagnetic interference

suppression intended for use within all kind of electric and electronic equipment.

In this generic specification, normative references and terms and definitions are given. It also

prescribes general requirements and the suitable test and measurement procedures for

interference suppression inductors. Annex B states special requirements for earth inductors.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies.

For undated references, the latest edition of the referenced document (including any

amendments) applies.

CISPR 17, Methods of measurement of the suppression characteristics of passive EMC filtering

devices
IEC 60027 (all parts), Letter symbols to be used in electrical technology

IEC 60050 (all parts), International Electrotechnical Vocabulary (IEV) (available at

www.electropedia.org)

IEC 60060-1, High-voltage test techniques – Part 1: General definitions and test requirements

IEC 60062, Marking codes for resistors and capacitors
IEC 60068-1, Environmental testing – Part 1: General and guidance
IEC 60068-2-1, Environmental testing – Part 2-1: Tests – Tests A: Cold
IEC 60068-2-2, Environmental testing – Part 2-2: Tests – Tests B: Dry Heat

IEC 60068-2-6, Environmental testing – Part 2-6: Tests – Test Fc: Vibration (sinusoidal)

IEC 60068-2-13, Environmental testing – Part 2-13: Tests – Test M: Low air pressure

IEC 60068-2-14, Environmental testing – Part 2-14: Tests – Test N: Change of temperature

IEC 60068-2-17, Basic environmental testing procedures – Part 2-17: Tests – Test Q: Sealing

IEC 60068-2-20, Environmental testing – Part 2-20: Tests – Test T: Test methods for

solderability and resistance to soldering heat of devices with leads
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IEC 60938-1:2021 © IEC 2021 – 9 –

IEC 60068-2-21, Environmental testing – Part 2-21: Tests – Test U: Robustness of terminations

and integral mounting devices

IEC 60068-2-27, Environmental testing – Part 2-27: Tests – Test Ea and guidance: Shock

IEC 60068-2-30, Environmental testing – Part 2-30: Tests – Test Db: Damp heat, cyclic

IEC 60068-2-45, Basic environmental testing procedures – Part 2-45: Tests – Test XA and

guidance: Immersion in cleaning solvents

IEC 60068-2-58, Environmental testing – Part 2-58: Tests – Test Td: Test methods for

solderability, resistance to dissolution of metallization and to soldering heat of surface mounting

devices (SMD).

IEC 60068-2-78, Environmental testing – Part 2-78: Tests – Test Cab: Damp heat, steady state

IEC 60335-1, Household and similar electrical appliances – Part 1: General requirements

IEC 60617, Graphical symbols for diagrams (available at http://std.iec.ch/iec60617)

IEC 60695-2-11, Fire hazard testing – Part 2-11: Glowing/hot-wire based test methods – Glow-

wire flammability test method for end-products (GWEPT)

IEC 60695-2-12, Fire hazard testing – Part 2-12: Glowing/hot-wire based test methods – Glow-

wire flammability index (GWFI) test method for materials

IEC 60695-2-13, Fire hazard testing – Part 2-13: Glowing/hot-wire based test methods – Glow-

wire ignition temperature (GWIT) test method for materials

IEC 60695-10-2, Fire hazard testing – Part 10-2: Abnormal heat – Ball pressure test method

IEC 60695-11-10, Fire hazard testing – Part 11-10: Test flames – 50 W horizontal and vertical

flame test methods

IEC 60695-11-20, Fire hazard testing – Part 11-20: Test flames – 500 W flame test method

ISO 80000-6, Quantities and units – Part 6: Electromagnetism
3 Terms, definitions and conventions

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
For the purposes of this document, the following terms and definitions apply.
3.1 Terms and definitions
3.1.1
choke
inductor

construction that employs one or more windings for a frequency-dependent impedance

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– 10 – IEC 60938-1:2021 © IEC 2021
3.1.2
rated voltage

maximum RMS operating voltage of the rated frequency or the maximum DC operating voltage

that can be applied continuously to the terminations of the inductor

Note 1 to entry: Because the rated voltage against any surrounding conducting surface is defined by the mounting

in the application, an inductor with only one winding can have no rated voltage.
3.1.3
lower category temperature

minimum surface temperature for which the inductor has been designed to operate continuously

3.1.4
upper catego
...