IEC 60539-2:2003

Directly heated negative temperature coefficient thermistors - Part 2: Sectional specification - Surface mount negative temperature coefficient thermistors

IEC 60539-2:2003 is applicable to surface mount directly heated negative temperature coefficient thermistors, typically made from transition metal oxide materials with semiconducting properties. These thermistors have metallized connecting pads or soldering strips and are intended to be mounted directly on to substrates for hybrid circuits or on to printed boards.

Thermistances à coefficient de température négatif à chauffage direct - Partie 2: Spécification intermédiaire - Thermistances à coefficient de température négatif pour montage en surface

La CEI 60539-2:2003 s'applique aux thermistances à coefficient de température négatif à chauffage direct pour montage en surface, typiquement constituées de matériaux faits d'oxyde de métal de transition dotés de propriétés semi-conductrices. Ces thermistances sont équipées de contacts de connexion métallisés ou de bandes de soudure et sont destinées à être montées directement sur des substrats pour circuits hybrides ou sur des cartes imprimées.

General Information

• Status: Published
• Publication Date: 28-Nov-2010
• ICS: 31.040.30 - Thermistors
• Technical Committee: TC 40 - Capacitors and resistors for electronic equipment
• Current Stage: DELPUB - Deleted Publication
• Start Date: 31-Jul-2017
• Completion Date: 19-Jul-2019

Relations

• Amended By: IEC 60539-2:2003/AMD1:2010 - Amendment 1 - Directly heated negative temperature coefficient thermistors - Part 2: Sectional specification - Surface mount negative temperature coefficient thermistors
• Effective Date: 05-Sep-2023
• Revised: IEC 60539-2:2019 - Directly heated negative temperature coefficient thermistors - Part 2: Sectional specification - Surface mount negative temperature coefficient thermistors
• Effective Date: 05-Sep-2023

Standards Content (Sample)

INTERNATIONAL IEC
STANDARD
60539-2
First edition
2003-11
Directly heated negative temperature
coefficient thermistors –
Part 2:
Sectional specification –
Surface mount negative temperature
coefficient thermistors
Reference number
Publication numbering
As from 1 January 1997 all IEC publications are issued with a designation in the

60000 series. For example, IEC 34-1 is now referred to as IEC 60034-1.

Consolidated editions
The IEC is now publishing consolidated versions of its publications. For example,

edition numbers 1.0, 1.1 and 1.2 refer, respectively, to the base publication, the

base publication incorporating amendment 1 and the base publication incorporating

amendments 1 and 2.
Further information on IEC publications
The technical content of IEC publications is kept under constant review by the IEC,
thus ensuring that the content reflects current technology. Information relating to
this publication, including its validity, is available in the IEC Catalogue of
publications (see below) in addition to new editions, amendments and corrigenda.
Information on the subjects under consideration and work in progress undertaken
by the technical committee which has prepared this publication, as well as the list
of publications issued, is also available from the following:
• IEC Web Site (www.iec.ch)
• Catalogue of IEC publications
The on-line catalogue on the IEC web site (www.iec.ch/searchpub) enables you to
search by a variety of criteria including text searches, technical committees
and date of publication. On-line information is also available on recently issued
publications, withdrawn and replaced publications, as well as corrigenda.
• IEC Just Published
This summary of recently issued publications (www.iec.ch/online_news/ justpub)
is also available by email. Please contact the Customer Service Centre (see
below) for further information.
• Customer Service Centre
If you have any questions regarding this publication or need further assistance,
please contact the Customer Service Centre:

Email: [e-mail]
Tel: [phone]
Fax: [phone]
INTERNATIONAL IEC
STANDARD
60539-2
First edition
2003-11
Directly heated negative temperature
coefficient thermistors –
Part 2:
Sectional specification –
Surface mount negative temperature
coefficient thermistors
 IEC 2003  Copyright - all rights reserved
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 the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: [phone] Telefax: [phone] E-mail: [e-mail]  Web: www.iec.ch
PRICE CODE
Commission Electrotechnique Internationale
S
International Electrotechnical Commission
Международная Электротехническая Комиссия
For price, see current catalogue

– 2 – 60539-2  IEC:2003(E)
CONTENTS
FOREWORD . 4

1 General . 6

1.1 Scope . 6

1.2 Normative references . 6

1.3 Information to be given in a detail specification. 6

1.3.1 Outline drawing and dimensions . 7

1.3.2 Mounting. 7
1.3.3 Ratings and characteristics. 7
1.4 Terminology. 7
2 Preferred ratings and characteristics. 7
2.1 Tolerances on rated zero-power resistance . 7
2.2 Climatic categories . 7
3 Quality assessment procedures . 8
3.1 Primary stage of manufacture . 8
3.2 Structurally similar components . 8
3.3 Qualification approval procedures. 8
3.3.1 The manufacturer shall comply with 3.4 of IEC 60539-1. 8
3.4 Quality conformance inspection . 8
3.4.1 Qualification approval on the basis of the fixed sample size
procedure . 8
3.5 Quality conformance inspection .10
3.5.1 Formation of inspection lots .10
3.5.2 Test schedule .11
3.5.3 Delayed delivery .11
3.5.4 Assessment level.11
4 Test and measurement procedures .12
4.1 Mounting .12
4.2 Drying and recovery.12
4.2.1 Drying.12
4.2.2 Recovery .12
4.3 Visual examination and check of dimensions .12
4.3.1 Visual examination.12
4.3.2 Requirements .12
4.3.3 Marking.14
4.3.4 Dimensions.14
4.4 Electrical tests .14
4.4.1 Zero-power resistance .14
4.4.2 B-value or resistance ratio .14
4.4.3 Resistance/temperature characteristic .15
4.5 Thermal tests.15
4.5.1 Dissipation factor (δ).15
4.5.2 Thermal time constant by cooling after self-heating (τ ).15
c
60539-2  IEC:2003(E) – 3 –
4.6 Resistance to soldering heat .15

4.6.1 Initial measurement .15

4.6.2 Test conditions .15

4.6.3 Recovery .16

4.6.4 Final inspection, measurements and requirements .16

4.7 Solderability .16

4.7.1 Test conditions .16

4.7.2 Recovery .17

4.7.3 Final inspection, measurements and requirements .17

4.8 Rapid change of temperature .17

4.9 Thermal shock.17
4.10 Climatic sequence .18
4.10.1 Initial measurements .18
4.10.2 Dry heat .18
4.10.3 Damp heat (cyclic), first cycle.18
4.10.4 Cold .18
4.10.5 Damp heat (cyclic), remaining cycles.18
4.10.6 Final measurements .19
4.11 Damp heat, steady state.19
4.12 Endurance.19
4.12.1 Endurance at θ and P .19
3 max.
4.12.2 Endurance at upper category temperature .19
4.13 Shear (adhesion) test .20
4.14 Substrate bending test .20
4.15 Component solvent resistance.20
4.16 Solvent resistance of marking.20
Annex A (normative) Guide for the specification and coding of dimensions of surface
mount negative temperature coefficient thermistors .21
Table 1 – Upper and lower category temperatures and duration of the damp heat test.8
Table 2 – Fixed sample size test schedule for qualification approval of surface mount
negative temperature coefficient thermistors Assessment level EZ .10
Table 3 – Lot-by-lot inspection.11
Table 4 – Periodic test .12

Table 5 – Number of cycles .18
Table A.1 – Dimensions .21
Figure 1 – Fault: fissure or defect .13
Figure 2 – Fault: crack .13
Figure 3 – Separation or delamination .13
Figure 4 – Exposed electrodes.13
Figure 5 – Principal faces .14
Figure A.1 – Dimensioning of surface mount thermistors.21

– 4 – 60539-2  IEC:2003(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
DIRECTLY HEATED NEGATIVE TEMPERATURE

COEFFICIENT THERMISTORS –
Part 2: Sectional specification –

Surface mount negative temperature coefficient thermistors

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, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with 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.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC
...

IEC 60539-2 ®
Edition 1.0 2003-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Directly heated negative temperature coefficient thermistors –
Part 2: Sectional specification – Surface mount negative temperature coefficient
thermistors
Thermistances à coefficient de température négatif à chauffage direct –
Partie 2: Spécification intermédiaire – Thermistances à coefficient de
température négatif pour montage en surface

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 la CEI ou du Comité national de la CEI du pays du demandeur.

Si vous avez des questions sur le copyright de la CEI ou si vous désirez obtenir des droits supplémentaires sur cette

publication, utilisez les coordonnées ci-après ou contactez le Comité national de la CEI de votre pays de résidence.

IEC Central Office
3, rue de Varembé
CH-1211 Geneva 20
Switzerland
Email: [e-mail]
Web: www.iec.ch
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 corrigenda or an amendment might have been published.
ƒ Catalogue of IEC publications: www.iec.ch/searchpub
The IEC on-line Catalogue enables you to search by a variety of criteria (reference number, text, technical committee,…).
It also gives information on projects, withdrawn and replaced publications.
ƒ IEC Just Published: www.iec.ch/online_news/justpub
Stay up to date on all new IEC publications. Just Published details twice a month all new publications released. Available
on-line and also by email.
ƒ Electropedia: www.electropedia.org
The world's leading online dictionary of electronic and electrical terms containing more than 20 000 terms and definitions
in English and French, with equivalent terms in additional languages. Also known as the International Electrotechnical
Vocabulary online.
ƒ Customer Service Centre: www.iec.ch/webstore/custserv
If you wish to give us your feedback on this publication or need further assistance, please visit the Customer Service
Centre FAQ or contact us:
Email: [e-mail]
Tel.: [phone]
Fax: [phone]
A propos de la CEI
La Commission Electrotechnique Internationale (CEI) 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 CEI
Le contenu technique des publications de la CEI est constamment revu. Veuillez vous assurer que vous possédez
l’édition la plus récente, un corrigendum ou amendement peut avoir été publié.
ƒ Catalogue des publications de la CEI: www.iec.ch/searchpub/cur_fut-f.htm
Le Catalogue en-ligne de la CEI vous permet d’effectuer des recherches en utilisant différents critères (numéro de référence,
texte, comité d’études,…). Il donne aussi des informations sur les projets et les publications retirées ou remplacées.
ƒ Just Published CEI: www.iec.ch/online_news/justpub
Restez informé sur les nouvelles publications de la CEI. Just Published détaille deux fois par mois les nouvelles
publications parues. Disponible en-ligne et aussi par email.
ƒ Electropedia: www.electropedia.org
Le premier dictionnaire en ligne au monde de termes électroniques et électriques. Il contient plus de 20 000 termes et
définitions en anglais et en français, ainsi que les termes équivalents dans les langues additionnelles. Egalement appelé
Vocabulaire Electrotechnique International en ligne.
ƒ Service Clients: www.iec.ch/webstore/custserv/custserv_entry-f.htm
Si vous désirez nous donner des commentaires sur cette publication ou si vous avez des questions, visitez le FAQ du
Service clients ou contactez-nous:
Email: [e-mail]
Tél.: [phone]
Fax: [phone]
IEC 60539-2 ®
Edition 1.0 2003-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Directly heated negative temperature coefficient thermistors –
Part 2: Sectional specification – Surface mount negative temperature coefficient
thermistors
Thermistances à coefficient de température négatif à chauffage direct –
Partie 2: Spécification intermédiaire – Thermistances à coefficient de
température négatif pour montage en surface

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
S
CODE PRIX
ICS 31.040.30 ISBN 978-2-88912-044-4
– 2 – 60539-2 © IEC:2003
CONTENTS
FOREWORD.4

1 General .6

1.1 Scope.6

1.2 Normative references .6

1.3 Information to be given in a detail specification .6

1.3.1 Outline drawing and dimensions .7

1.3.2 Mounting .7

1.3.3 Ratings and characteristics.7
1.4 Terminology .7
2 Preferred ratings and characteristics .7
2.1 Tolerances on rated zero-power resistance .7
2.2 Climatic categories.7
3 Quality assessment procedures.8
3.1 Primary stage of manufacture.8
3.2 Structurally similar components.8
3.3 Qualification approval procedures .8
3.3.1 The manufacturer shall comply with 3.4 of IEC 60539-1.8
3.4 Quality conformance inspection.8
3.4.1 Qualification approval on the basis of the fixed sample size
procedure .8
3.5 Quality conformance inspection.10
3.5.1 Formation of inspection lots.10
3.5.2 Test schedule .11
3.5.3 Delayed delivery.11
3.5.4 Assessment level.11
4 Test and measurement procedures.12
4.1 Mounting .12
4.2 Drying and recovery .12
4.2.1 Drying .12
4.2.2 Recovery .12
4.3 Visual examination and check of dimensions.12
4.3.1 Visual examination .12
4.3.2 Requirements .12

4.3.3 Marking .14
4.3.4 Dimensions .14
4.4 Electrical tests.14
4.4.1 Zero-power resistance .14
4.4.2 B-value or resistance ratio .14
4.4.3 Resistance/temperature characteristic .15
4.5 Thermal tests .15
4.5.1 Dissipation factor (δ).15
4.5.2 Thermal time constant by cooling after self-heating (τ ).15
c
4.6 Resistance to soldering heat .15
4.6.1 Initial measurement .15
4.6.2 Test conditions .15
4.6.3 Recovery .16

60539-2 © IEC:2003 – 3 –
4.6.4 Final inspection, measurements and requirements .16

4.7 Solderability .16

4.7.1 Test conditions .16

4.7.2 Recovery .17

4.7.3 Final inspection, measurements and requirements .17

4.8 Rapid change of temperature .17

4.9 Thermal shock.17

4.10 Climatic sequence .18

4.10.1 Initial measurements .18

4.10.2 Dry heat .18
4.10.3 Damp heat (cyclic), first cycle.18
4.10.4 Cold .18
4.10.5 Damp heat (cyclic), remaining cycles.18
4.10.6 Final measurements .19
4.11 Damp heat, steady state.19
4.12 Endurance.19
θ and P .19
4.12.1 Endurance at
3 max.
4.12.2 Endurance at upper category temperature .19
4.13 Shear (adhesion) test .20
4.14 Substrate bending test .20
4.15 Component solvent resistance.20
4.16 Solvent resistance of marking.20
Annex A (normative) Guide for the specification and coding of dimensions of surface
mount negative temperature coefficient thermistors .21
Figure 1 – Fault: fissure or defect .13
Figure 2 – Fault: crack .13
Figure 3 – Separation or delamination .13
Figure 4 – Exposed electrodes.13
Figure 5 – Principal faces .14
Figure A.1 – Dimensioning of surface mount thermistors.21
Table 1 – Upper and lower category temperatures and duration of the damp heat test.8
Table 2 – Fixed sample size test schedule for qualification approval of
...

IEC 60539-2 ®
Edition 1.1 2010-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Directly heated negative temperature coefficient thermistors –
Part 2: Sectional specification – Surface mount negative temperature coefficient
thermistors
Thermistances à coefficient de température négatif à chauffage direct –
Partie 2: Spécification intermédiaire – Thermistances à coefficient de
température négatif pour montage en surface

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 la CEI ou du Comité national de la CEI du pays du demandeur.

Si vous avez des questions sur le copyright de la CEI ou si vous désirez obtenir des droits supplémentaires sur cette

publication, utilisez les coordonnées ci-après ou contactez le Comité national de la CEI de votre pays de résidence.

IEC Central Office
3, rue de Varembé
CH-1211 Geneva 20
Switzerland
Email: [e-mail]
Web: www.iec.ch
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 corrigenda or an amendment might have been published.
§ Catalogue of IEC publications: www.iec.ch/searchpub
The IEC on-line Catalogue enables you to search by a variety of criteria (reference number, text, technical committee,…).
It also gives information on projects, withdrawn and replaced publications.
§ IEC Just Published: www.iec.ch/online_news/justpub
Stay up to date on all new IEC publications. Just Published details twice a month all new publications released. Available
on-line and also by email.
§ Electropedia: www.electropedia.org
The world's leading online dictionary of electronic and electrical terms containing more than 20 000 terms and definitions
in English and French, with equivalent terms in additional languages. Also known as the International Electrotechnical
Vocabulary online.
§ Customer Service Centre: www.iec.ch/webstore/custserv
If you wish to give us your feedback on this publication or need further assistance, please visit the Customer Service
Centre FAQ or contact us:
Email: [e-mail]
Tel.: [phone]
Fax: [phone]
A propos de la CEI
La Commission Electrotechnique Internationale (CEI) 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 CEI
Le contenu technique des publications de la CEI est constamment revu. Veuillez vous assurer que vous possédez
l’édition la plus récente, un corrigendum ou amendement peut avoir été publié.
§ Catalogue des publications de la CEI: www.iec.ch/searchpub/cur_fut-f.htm
Le Catalogue en-ligne de la CEI vous permet d’effectuer des recherches en utilisant différents critères (numéro de référence,
texte, comité d’études,…). Il donne aussi des informations sur les projets et les publications retirées ou remplacées.
§ Just Published CEI: www.iec.ch/online_news/justpub
Restez informé sur les nouvelles publications de la CEI. Just Published détaille deux fois par mois les nouvelles
publications parues. Disponible en-ligne et aussi par email.
§ Electropedia: www.electropedia.org
Le premier dictionnaire en ligne au monde de termes électroniques et électriques. Il contient plus de 20 000 termes et
définitions en anglais et en français, ainsi que les termes équivalents dans les langues additionnelles. Egalement appelé
Vocabulaire Electrotechnique International en ligne.
§ Service Clients: www.iec.ch/webstore/custserv/custserv_entry-f.htm
Si vous désirez nous donner des commentaires sur cette publication ou si vous avez des questions, visitez le FAQ du
Service clients ou contactez-nous:
Email: [e-mail]
Tél.: [phone]
Fax: [phone]
IEC 60539-2 ®
Edition 1.1 2010-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Directly heated negative temperature coefficient thermistors –
Part 2: Sectional specification – Surface mount negative temperature coefficient
thermistors
Thermistances à coefficient de température négatif à chauffage direct –
Partie 2: Spécification intermédiaire – Thermistances à coefficient de
température négatif pour montage en surface

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CH
CODE PRIX
ICS 31.040.30 ISBN 978-2-88912-248-6
– 2 – 60539-2 Ó IEC:2003+A1:2010

CONTENTS
FOREW ORD . 4

1 General . 6

1.1 Scope . 6

1.2 Normative references . 6

1.3 Information to be given in a detail specification . 7

1.3.1 Outline drawing and dimensions . 7

1.3.2 Mounting . 7

1.3.3 Ratings and characteristics . 7
1.4 Terminology . 7
2 Preferred ratings and characteristics . 7
2.1 Tolerances on rated zero-power resistance . 7
2.2 Climatic categories . 8
3 Quality assessment procedures . 8
3.1 Primary stage of manufacture . 8
3.2 Structurally similar components . 8
3.3 Qualification approval procedures . 8
3.3.1 The manufacturer shall comply with 3.4 of IEC 60539-1. . 8
3.4 Quality conformance inspection . 8
3.4.1 Qualification approval on the basis of the fixed sample size
p roced u re . 9
3.5 Quality conformance inspection . 10
3.5.1 Formation of inspection lots . 10
3.5.2 Test schedule . 11
3.5.3 Delayed delivery . 11
3.5.4 Assessment level . 11
4 Test and measurement procedures . 12
4.1 Mounting . 12
4.2 Drying and recovery . 12
4.2.1 Drying . 12
4.2.2 Recov ery . 12
4.3 Visual examination and check of dimensions. 12
4.3.1 Visual examination . 12
4.3.2 Requirements . 12

4.3.3 Marking . 14
4.3.4 Dimensions . 14
4.4 Electrical tests . 14
4.4.1 Zero-power resistance . 14
4.4.2 B-value or resistance ratio. 14
4.4.3 Resistance/temperature characteristic . 15
4.5 Thermal tests. 15
4.5.1 Dissipation factor (d) . 15
4.5.2 Thermal time constant by cooling after self-heating (t
) . 15
c
4.6 Resistance to soldering heat . 15
4.6.1 Initial measurement . 15
4.6.2 Test conditions . 15
4.6.3 Recov ery . 16

60539-2 Ó IEC:2003+A1:2010 – 3 –

4.6.4 Final inspection, measurements and requirements . 16

4.7 Solderability . 16

4.7.1 Test conditions . 16

4.7.2 Recov ery . 17

4.7.3 Final inspection, measurements and requirements . 17

4.8 Rapid change of temperature . 17

4.9 Thermal shock . 18

4.10 Climatic sequence . 18

4.10.1 Initial measurements . 18

4.10.2 Dry heat . 18

4.10.3 Damp heat (cyclic), first cycle . 18
4.10.4 Cold . 18
4.10.5 Damp heat (cyclic), remaining cycles . 18
4.10.6 Final measurements . 19
4.11 Damp heat, steady state . 19
4.12 Endurance . 19
4.12.1 Endurance at q and P . 19
3 max.
4.12.2 Endurance at upper category temperature . 20
4.13 Shear (adhesion) test . 20
4.14 Substrate bending test . 20
4.15 Component solvent resistance . 20
4.16 Solvent resistance of marking . 20
Annex A (normative) Guide for the specification and coding of dimensions of surface
mount negative temperature coefficient thermistors. 21

Figure 1 – Fault: fissure or defect . 13
Figure 2 – Fault: crack . 13
Figure 3 – Separation or delamination . 13
Figure 4 – Exposed electrodes . 13
Figure 5 – Principal faces . 14
Figure A.1 – Dimensioning of surface mount thermistors . 21

Table 1 – Upper and lower category temperatures and duration of the damp heat test . 8
Table 2 – Fixed sample size test schedule for qualification approval of surface mount

negative temperature coefficient thermistors Assessment level EZ . 10
Table 3 – Lot-by-lot inspection . 11
Table 4 – Periodic
...