IEC 60539-1:2022

Directly heated negative temperature coefficient thermistors - Part 1: Generic specification

IEC 60539-1:2022 is applicable to directly heated negative temperature coefficient thermistors, typically made from transition metal oxide materials with semiconducting properties.
It establishes standard terms, inspection procedures and methods of test for use in sectional and detail specifications of electronic components for quality assessment or any other purpose.
This edition includes the following significant technical changes with respect to the previous edition:  
Restructured completely to comply to ISO/IEC directives; categorization and reorganization of test methods into these categories;
Annex X added for comparison to the previous edition;
Some wordings, figures and references have been revised.

Thermistances à coefficient de température négatif à chauffage direct - Partie 1: Spécification générique

L’IEC 60539-1:2022 s’applique aux thermistances à coefficient de température négatif à chauffage direct, généralement constituées d’oxydes de métaux de transition présentant des propriétés semi-conductrices.
Elle établit des termes, des procédures d’inspection et des méthodes d’essai normaux à utiliser dans les spécifications intermédiaires et particulières des composants électroniques, pour l’assurance de la qualité ou pour tout autre usage.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l’édition précédente:  
cette édition a été entièrement remaniée conformément aux Directives ISO/IEC; différentes catégories ont été définies et les méthodes d’essai ont été réorganisées en fonction de ces catégories;
l’Annexe X a été ajoutée à titre de comparaison par rapport à l’édition précédente;
certaines formulations, figures et références ont été révisées.

General Information

• Status: Published
• Publication Date: 14-Dec-2022
• ICS: 31.040.30 - Thermistors
• Technical Committee: TC 40 - Capacitors and resistors for electronic equipment
• Drafting Committee: MT 60539-1 - TC 40/MT 60539-1
• Current Stage: PPUB - Publication issued
• Start Date: 06-Jan-2023
• Completion Date: 15-Dec-2022

Relations

• Revises: IEC 60539-1:2016 - Directly heated negative temperature coefficient thermistors - Part 1: Generic specification
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 60539-1
®

Edition 4.0 2022-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE


Directly heated negative temperature coefficient thermistors –
Part 1: Generic specification

Thermistances à coefficient de température négatif à chauffage direct –
Partie 1: Spécification générique

IEC 60539-1:2022-12(en-fr)

---------------------- Page: 1 ----------------------
THIS PUBLICATION IS COPYRIGHT PROTECTED
Copyright © 2022 IEC, Geneva, Switzerland

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.


Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite ni
utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie et
les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des
questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.

IEC Secretariat Tel.: [phone]
3, rue de Varembé [e-mail]
CH-1211 Geneva 20 www.iec.ch
Switzerland

About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform IEC Products & Services Portal - products.iec.ch
The advanced search enables to find IEC publications by a Discover our powerful search engine and read freely all the
variety of criteria (reference number, text, technical publications previews. With a subscription you will always have
committee, …). It also gives information on projects, replaced access to up to date content tailored to your needs.
and withdrawn publications.

Electropedia - www.electropedia.org
IEC Just Published - webstore.iec.ch/justpublished
The world's leading online dictionary on electrotechnology,
Stay up to date on all new IEC publications. Just Published
containing more than 22 300 terminological entries in English
details all new publications released. Available online and once
and French, with equivalent terms in 19 additional languages.
a month by email.
Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Customer Service Centre - webstore.iec.ch/csc
If you wish to give us your feedback on this publication or need
further assistance, please contact the Customer Service
Centre: [e-mail].


A propos de l'IEC
La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des
Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications IEC
Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la
plus récente, un corrigendum ou amendement peut avoir été publié.

Recherche de publications IEC - Découvrez notre puissant moteur de recherche et consultez
webstore.iec.ch/advsearchform gratuitement tous les aperçus des publications. Avec un
La recherche avancée permet de trouver des publications IEC abonnement, vous aurez toujours accès à un contenu à jour
en utilisant différents critères (numéro de référence, texte, adapté à vos besoins.
comité d’études, …). Elle donne aussi des informations sur les
projets et les publications remplacées ou retirées. Electropedia - www.electropedia.org

Le premier dictionnaire d'électrotechnologie en ligne au monde,
IEC Just Published - webstore.iec.ch/justpublished
avec plus de 22 300 articles terminologiques en anglais et en
Restez informé sur les nouvelles publications IEC. Just
français, ainsi que les termes équivalents dans 19 langues
Published détaille les nouvelles publications parues.
additionnelles. Egalement appelé Vocabulaire
Disponible en ligne et une fois par mois par email.
Electrotechnique International (IEV) en ligne.


Service Clients - webstore.iec.ch/csc
Si vous désirez nous donner des commentaires sur cette
publication ou si vous avez des questions contactez-nous:
[e-mail].
IEC Products & Services Portal - products.iec.ch

---------------------- Page: 2 ----------------------
IEC 60539-1

®


Edition 4.0 2022-12




INTERNATIONAL



STANDARD




NORME


INTERNATIONALE











Directly heated negative temperature coefficient thermistors –

Part 1: Generic specification



Thermistances à coefficient de température négatif à chauffage direct –

Partie 1: Spécification générique
















INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE


INTERNATIONALE




ICS 31.040.30 ISBN 978-2-8322-6192-7




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 60539-1:2022 © IEC 2022
CONTENTS
FOREWORD . 8
1 Scope . 10
2 Normative references . 10
3 Terms and definitions . 11
4 General items . 21
4.1 Units and symbols. 21
4.2 Preferred values and appropriate category . 21
4.2.1 General . 21
4.2.2 Appropriate category . 21
4.3 Marking . 21
4.3.1 General . 21
4.3.2 Marking for small size types such as surface mount NTC thermistors . 22
4.3.3 Coding . 22
4.4 Quality assessment procedures . 22
5 General provisions for measurements and test methods . 22
5.1 General . 22
5.2 Standard atmospheric conditions for testing . 22
5.3 Drying and recovery . 23
5.3.1 Drying . 23
5.3.2 Recovery . 23
5.4 Mounting (for surface mount thermistors only) . 23
5.4.1 General . 23
5.4.2 Printed wiring board and land pattern . 23
5.4.3 Mounting on board . 23
6 Electrical tests and measurements . 25
6.1 Zero-power resistance . 25
6.1.1 General . 25
6.1.2 Measurement procedures . 25
6.1.3 Requirements . 25
6.2 B-value or resistance ratio . 25
6.2.1 General . 25
6.2.2 Requirements . 25
6.3 Insulation resistance (for insulated types only) . 26
6.3.1 General . 26
6.3.2 Test methods . 26
6.3.3 Applied voltage . 29
6.3.4 Requirements . 29
6.4 Voltage proof (for insulated types only) . 29
6.4.1 General . 29
6.4.2 Test voltage . 29
6.4.3 Requirements . 29
6.5 Resistance/temperature characteristic . 29
6.5.1 General . 29
6.5.2 Test methods . 29
6.5.3 Requirements . 29
6.6 Dissipation factor (δ) . 30

---------------------- Page: 4 ----------------------
IEC 60539-1:2022 © IEC 2022 – 3 –
6.6.1 General . 30
6.6.2 Initial measurements . 30
6.6.3 Test methods . 30
6.6.4 Requirements . 31
6.7 Thermal time constant by ambient temperature change (τ ) . 31
a
6.7.1 The hot to cold thermal time constant for ambient temperature change . 31
6.7.2 The cold to hot thermal time constant for ambient temperature change . 32
6.7.3 Final measurements and requirements . 32
6.7.4 Requirements . 33
6.8 Thermal time constant by cooling after self-heating (τ ) . 33
c
6.8.1 General . 33
6.8.2 Initial measurements . 33
6.8.3 Preconditioning . 33
6.8.4 Test method . 34
6.8.5 Final measurements and requirements . 34
7 Mechanical test and measurements . 34
7.1 Visual examination and check of dimensions . 34
7.1.1 Visual examination . 34
7.1.2 Dimensions . 35
7.2 Robustness of terminations (not applicable to surface mount thermistors) . 35
7.2.1 General . 35
7.2.2 Initial measurements . 35
7.2.3 Test methods . 35
7.2.4 Test Ua – Tensile . 35
1
7.2.5 Test Ub – Bending (half the number of terminations) . 36
7.2.6 Test Uc – Torsion (remaining terminations). 36
7.2.7 Final measurements and requirements . 36
7.3 Vibration . 36
7.3.1 General . 36
7.3.2 Initial measurements . 36
7.3.3 Test procedures . 36
7.3.4 Final inspection, measurements and requirements. 37
7.4 Shock . 37
7.4.1 General . 37
7.4.2 Initial measurements . 37
7.4.3 Mounting . 37
7.4.4 Test procedures . 37
7.4.5 Final inspection, measurements and requirements. 37
7.5 Free fall . 37
7.5.1 General . 37
7.5.2 Initial measurements . 37
7.5.3 Test procedures . 38
7.5.4 Final inspection, measurements and requirements. 38
7.6 Shear (adhesion) test (for surface mount NTC thermistors only) . 38
7.6.1 General . 38
7.6.2 Initial measurements . 38
7.6.3 Test conditions . 38
7.6.4 Final inspection, measurements and requirements. 38

---------------------- Page: 5 ----------------------
– 4 – IEC 60539-1:2022 © IEC 2022
7.7 Substrate bending test (for surface mount NTC thermistors only) . 38
7.7.1 General . 38
7.7.2 Initial measurements . 38
7.7.3 Test procedures . 38
7.7.4 Final inspection, measurements and requirements. 39
8 Environmental and climatic tests . 39
8.1 Rapid change of temperature . 39
8.1.1 General . 39
8.1.2 Initial measurements . 39
8.1.3 Test procedures . 39
8.1.4 Final inspection, measurements and requirements. 39
8.2 Thermal shock . 40
8.2.1 General . 40
8.2.2 Initial measurements . 40
8.2.3 Test procedures . 40
8.2.4 Final inspection, measurements and requirements. 40
8.3 Cold . 40
8.3.1 General . 40
8.3.2 Initial measurements . 40
8.3.3 Test procedures . 40
8.3.4 Final inspection, measurements and requirements. 41
8.4 Dry heat . 41
8.4.1 General . 41
8.4.2 Initial measurements . 41
8.4.3 Test procedures . 41
8.4.4 Final inspection, measurements and requirements. 41
8.5 Damp heat, steady state . 42
8.5.1 General . 42
8.5.2 Initial measurements . 42
8.5.3 Test procedures . 42
8.5.4 Recovery . 42
8.5.5 Final inspection, measurements and requirements. 42
8.6 Endurance . 42
8.6.1 General . 42
8.6.2 Endurance at room temperature with applied continuous maximum
current (I ) (for inrush current-limiting thermistors only) . 43
max25
8.6.3 Endurance at room temperature with applied cyclic maximum current
(I ) (for inrush current-limiting thermistors only) . 44
max25
8.6.4 Endurance at T and P (for other than inrush current-limiting
3 max

thermistors only) . 45
8.6.5 Endurance at upper category temperature . 46
8.6.6 Maximum permissible capacitance (for inrush current-limiting
thermistors only) . 47
8.7 Salt mist . 49
8.7.1 General . 49
8.7.2 Initial measurements . 49
8.7.3 Test conditions . 49
8.7.4 Final inspection, measurements and requirements. 49
8.8 Sealing . 49

---------------------- Page: 6 ----------------------
IEC 60539-1:2022 © IEC 2022 – 5 –
8.9 Composite temperature/humidity cycle . 49
8.9.1 General . 49
8.9.2 Initial measurements . 49
8.9.3 Test conditions . 50
8.9.4 Final inspection, measurements and requirements. 50
9 Tests related to component assembly . 50
9.1 Resistance to soldering heat . 50
9.1.1 General . 50
9.1.2 Preconditioning . 50
9.1.3 Initial measurements . 50
9.1.4 Test procedure . 50
9.1.5 Recovery . 50
9.1.6 Final inspection, measurement and requirements . 51
9.2 Solderability . 51
9.2.1 General . 51
9.2.2 Initial measurements . 51
9.2.3 Test procedure . 51
9.2.4 Final inspection, measurements and requirements. 51
9.3 Component solvent resistance . 52
9.3.1 General . 52
9.3.2 Initial measurements . 52
9.3.3 Test conditions . 52
9.3.4 Requirements . 52
9.4 Solvent resistance of marking . 52
9.4.1 General . 52
9.4.2 Initial measurements . 52
9.4.3 Test conditions . 52
9.4.4 Requirements . 52
Annex A (normative) Rules for the preparation of detail specifications for directly
heated NTC thermistors for electronic equipment for use within quality assessment
systems . 53
A.1 Drafting . 53
A.2 Reference standard . 53
A.3 Circulation . 53
Annex B (informative) Typical examples of mountings for measurements of directly
heated thermistors . 54
Annex Q (informative) Quality assessment procedures . 56
Q.1 General . 56
Q.1.1 Scope of this annex . 56
Q.1.2 Quality assessment definitions . 57
Q.1.3 Rework . 57
Q.1.4 Alternative test methods . 57
Q.1.5 Certified test records of released lots . 58
Q.1.6 Unchecked parameters . 58
Q.1.7 Delayed delivery . 58
Q.1.8 Repair . 58
Q.1.9 Registration of approvals . 58
Q.1.10 Manufacture outside the geographical limits . 59
Q.2 Qualification approval (QA) procedures . 59

---------------------- Page: 7 ----------------------
– 6 – IEC 60539-1:2022 © IEC 2022
Q.2.1 Eligibility for qualification approval . 59
Q.2.2 Application for qualification approval . 59
Q.2.3 Subcontracting . 59
Q.2.4 Test procedure for the initial product qualification approval. 59
Q.2.5 Granting of qualification approval . 59
Q.2.6 Maintenance of qualification approval . 59
Q.2.7 Quality conformance inspection . 60
Q.3 Capability approval (CA) procedures . 60
Q.3.1 General . 60
Q.3.2 Eligibility for capability approval . 60
Q.3.3 Application for capability approval .
...