IEC 60738-1:2006+AMD1:2009 CSV

Thermistors - Directly heated positive temperature coefficient -Part 1: Generic specification

IEC 60738-1:2006+A1:2009 Prescribes terms and methods of test for positive step-function temperature coefficient thermistors, insulated and non-insulated types typically made from ferro-electric semi-conductor materials. It establishes standard terms, inspection procedures and methods of test for use in detail specifications for Qualification Approval and for Quality Assessment Systems for electronic components.
This consolidated version consists of the third edition (2006) and its amendment 1 (2009). Therefore, no need to order amendments in addition to this publication.

Thermistances - Coefficient de température positif à chauffagedirect - Partie 1: Spécification générique

L'IEC 60738-1:2006+A1:2009 décrit des termes et des méthodes d'essais pour les thermistances à basculement à coefficient de température positif, de type isolés ou non isolés, normalement fabriqués à partir de matériaux semiconducteurs ferroélectriques. Elle établit des termes normalisés, des procédures de contrôle et des méthodes d'essais destinés aux spécifications particulières pour l'homologation et pour les systèmes d'assurance de la qualité des composants électroniques. Cette troisième édition annule et remplace la deuxième édition parue en 1998 dont elle constitue une révision mineure. Les modifications par rapport à l'édition antérieure portent sur les tableaux, les figures et les références.  Cette version consolidée comprend la première édition (2006) et son amendement 1 (2009). Il n'est donc pas nécessaire de commander l'amendement avec cette publication.

General Information

• Status: Published
• Publication Date: 29-Jul-2009
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 31.040.30 - Thermistors
• Technical Committee: TC 40 - Capacitors and resistors for electronic equipment
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 14-Oct-2022

Standards Content (Sample)

IEC 60738-1
®

Edition 3.1 2009-07
CONSOLIDATED
VERSION
VERSION
CONSOLIDÉE
colour
inside


Thermistors – Directly heated positive temperature coefficient –
Part 1: Generic specification

Thermistances – Coefficient de température positif à chauffage direct –
Partie 1: Spécification générique

IEC 60738-1:2006-04+AMD1:2009-05 CSV(EN-FR)

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IEC 60738-1

®


Edition 3.1 2009-07




CONSOLIDATED



VERSION




VERSION



CONSOLIDÉE
colour

inside










Thermistors – Directly heated positive temperature coefficient –

Part 1: Generic specification




Thermistances – Coefficient de température positif à chauffage direct –

Partie 1: Spécification générique
















INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE

INTERNATIONALE



ICS 31.040.30 ISBN 978-2-8322-1370-4




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 ----------------------
IEC 60738-1
®

Edition 3.1 2009-07
REDLINE VERSION
VERSION REDLINE
colour
inside


Thermistors – Directly heated positive temperature coefficient –
Part 1: Generic specification

Thermistances – Coefficient de température positif à chauffage direct –
Partie 1: Spécification générique

IEC 60738-1:2006-04+AMD1:2009-05 CSV(EN-FR)

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– 2 – 60738-1  IEC:2006+A1:2009
CONTENTS
FOREWORD . 5

1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Units and symbols . 16
5 Preferred values . 17
5.1 Climatic categories . 17
5.2 Marking . 17
5.3 Spacings . 18
6 Quality assessment procedures . 18
6.1 General . 18
6.2 Primary stage of manufacture . 19
6.3 Subcontracting . 19
6.4 Structurally similar components . 19
6.5 Qualification approval procedures . 20
6.6 Rework and repair . 27
6.7 Release for delivery . 27
6.8 Certified test records of released lots . 28
6.9 Delayed delivery . 28
6.10 Alternative test methods . 28
6.11 Manufacture outside the geographical limits of IECQ NSIs . 28
6.12 Unchecked parameters . 28
7 Test and measurement procedures . 28
7.1 General . 28
7.2 Standard conditions for testing . 29
7.3 Drying and recovery . 29
7.4 Visual examination and check of dimensions . 30
7.5 Zero-power resistance . 30
7.6 Temperature coefficient of resistance . 31
7.7 Insulation resistance (for insulated types only) . 31
7.8 Voltage proof (for insulated types only) . 32
7.9 Resistance/temperature characteristic . 32
7.10 Dissipation factor at U (δ) . 33
max
7.11 Response time by ambient temperature change (t ) . 34
a
7.12 Response time by power change (t ) . 34
p
7.13 Thermal time constant by ambient temperature change (τ ) . 35
a
7.14 Thermal time constant by cooling (τ ). 35
c
7.15 Robustness of terminations . 37
7.16 Solderability . 38
7.17 Resistance to soldering heat . 39
7.18 Rapid change of temperature . 40
7.19 Vibration. 40
7.20 Bump . 40
7.21 Shock . 41

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60738-1  IEC:2006+A1:2009 – 3 –
7.22 Climatic sequence . 41
7.23 Damp heat, steady state . 42
7.24 Endurance . 43
7.25 Tripping current and tripping time . 47
7.26 Non-tripping current . 47
7.27 Residual current . 47
7.28 Surface temperature . 48
7.29 Inrush current . 49
7.30 Mounting (for surface mount thermistors only) . 49
7.31 Shear (adhesion) test . 50
7.32 Substrate bending test . 51

Annex A (normative) Interpretation of sampling plans and procedures as described in
IEC 60410 for use within the IEC quality assessment system for electronic
components (IECQ) . 52
Annex B (informative) Mounting for electrical measurements (except surface mount
types) . 53
Annex C (informative) Mounting for temperature measurements . 56

Figure 1 – Typical resistance-temperature characteristic and definitions for PTC
thermistors (at zero power) . 10
Figure 2 – Typical R-TNF characteristic for PTC thermistors in sensor applications . 11
Figure 3 – Typical current/voltage characteristic for PTC thermistors . 11
Figure 4 – I against t at U . 14
in dc
Figure 5 – I against t at U . 15
in rms
Figure 6 – Dissipation factor test circuit . 33
Figure 7 – Temperature gradient . 34
Figure 8 – Circuit for measurement of thermal time constant by cooling . 36
Figure 9 – Circuit for endurance at maximum operating temperature and maximum
voltage . 45
Figure 10 – Circuit for surface temperature measurement . 48
Figure 11 – Measuring circuit . 49
Figure B.1 – Example of a preferred mounting method for thermistors without wire
terminations . 53
Figure B.2 – Example of a preferred mounting method for thermistors with wire
terminations . 54
Figure B.3 – Example of a preferred mounting method for surface mount thermistors . 55
Figure C.1 – Example of a preferred mounting method for temperature measurement
on cylindrical heating elements . 56

Table 1 – Creepage distances and clearances . 18
Table 2 – Fixed sample size test schedule for qualification approval of thermistors for
current limitation – Assessment level EZ . 22
Table 3 – Fixed sample size test schedule for qualification approval of thermistors for
use as heating elements – Assessment level EZ . 23
Table 4 – Fixed sample size test schedule for qualification approval of thermistors for
inrush current application – Assessment level EZ . 24
Table 5 – Fixed sample size test schedule for qualification approval of thermistors for
use as temperature sensing elements, Assessment level EZ . 25

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– 4 – 60738-1  IEC:2006+A1:2009
Table 6 – Quality conformance inspection for lot-by-lot inspection . 26
Table 7 – Quality conformance inspection for periodic testing . 27
Table 8 – Tensile force . 37
Table 9 – Number of cycles per climatic category . 42

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60738-1  IEC:2006+A1:2009 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

THERMISTORS – DIRECTLY HEATED POSITIVE
TEMPERATURE COEFFICIENT –

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,
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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.
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consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
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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.

This Consolidated version of IEC 60738-1 bears the edition number 3.1. It consists of
the third edition (2006-04) [documents 40/1651/FDIS and 40/1730/RVD] and its
amendment 1 (2009-05) [documents 40/1940/CDV and 40/1999/RVC]. The technical
content is identical to the base edition and its amendment.
In this Redline version, a vertical line in the margin shows where the technical content
is modified by amendment 1. Additions and deletions are displayed in red, with
deletions being struck through. A separate Final version with all changes accepted is
available in this publication.
This publication has been prepared for user convenience.

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– 6 – 60738-1  IEC:2006+A1:2009
International Standard IEC 60738-1 has been prepared by IEC technical committee 40:
Capacitors and resistors for electronic equipment.
The French version of this standard has not been voted upon.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
IEC 60738 consists of the following parts, under the general title Thermistors – Directly
heated positive step-function coefficient:
Part 1: Generic specification
Part 1-1: Blank detail specification – Current limiting application – Assessment level EZ
Part 1-2: Blank detail specification – Heating element application – Assessment level EZ
Part 1-3: Blank detail specification – Inrush current application – Assessment level EZ
Part 1-4: Blank detail specification – Sensing application – Assessment level EZ
The committee has decided that the contents of the base publication and its amendment will
remain unchanged until the stability date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the
publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.

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60738-1  IEC:2006+A1:2009 – 7 –
THERMISTORS – DIRECTLY HEATED POSITIVE
TEMPERATURE COEFFICIENT –

Part 1: Generic specification



1 Scope
This part of IEC 60738 describes terms and methods of test for positive step-function
temperature coefficient thermistors, insulated and non-insulated types typically made from
ferro-electric semi-conductor materials.
It establishes standard terms, inspection procedures and methods of test for use in detail
specifications for Qualification Approval and for Quality Assessment Systems for electronic
components.
2 Normative references
The following referenced documents are indispensable for the application 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.
IEC 60027 (all parts), Letter symbols to be used in electrical technology
IEC 60050 (all parts), International Electrotechnical Vocabulary (IEV)
IEC 60062, Marking codes for resistors and capacitors
IEC 60068-1:1988, Environmental testing – Part 1: General and guidance
Amendment 1 (1992)
IEC 60068-2-1:1990, Environmental testing – Part 2: Tests – Tests A: Cold
Amendment 1 (1993)
Amendment 2 (1994)
IEC 60068-2-2:1974, Environmental testing – Part 2: Tests – Tests B: Dry heat
Amendment 1 (1993)
IEC 60068-2-6, Environmental testing – Part 2: Tests – Test Fc: Vibration (sinusoidal)
IEC 60068-2-11, Environmental testing – Part 2: Tests – Test Ka: Salt mist
IEC 60068-2-13, Environmental testing – Part 2: Tests – Test M: Low air pressure
IEC 60068-2-14:1984, Environmental testing – Part 2: Tests – Test N: Change of temperature
Amendment 1 (1986)
IEC 60068-2-20:1979, Environmental testing – Part 2: Tests – Test T: Soldering
Amendment 2 (1987)
IEC 60068-2-21, Environmental testing – Part 2-21: Tests – Test U: Robustness of
terminations and integral mounting devices

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– 8 – 60738-1  IEC:2006+A1:2009
IEC 60068-2-27, Environmental testing – Part 2: Tests – Test Ea and guidance: Shock
IEC 60068-2-29, Environmental testing – Part 2: Tests – Test Eb and guidance: Bump
IEC 60068-2-30:2005, Environmental testing – Part 2: Tests – Test Db: Damp heat, cyclic
(12 h + 12-hour cycle)
IEC 60068-2-45:1980, Environmental testing – Part 2: 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 60294, Measurement of the dimensions of a cylindrical component having two axial
terminations
IEC 60410, Sampling plans and procedures for inspection by attributes
1
IEC 60617 (all parts) [DB] : Graphical symbols for diagrams
IEC 60717, Method for determination of the space required by capacitors and resistors with
unidirectional terminations
IEC 61249-2-7, Materials for printed boards and other interconnecting structures – Part 2-7:
Reinforced base materials clad and unclad – Epoxide woven E-glass laminated sheet of
defined flammability (vertical burning test), copper-clad
IEC 61760-1, Surface mounting technology – Part 1: Standard method for the specification of
surface mounting components (SMDs)
IEC QC 001002-3, Rules of Procedure of the IEC Quality Assessment System for Electronic
Components (IECQ) – Part 3: Approval procedures
ISO 1000, SI units and recommendations for the use of their multiples and of certain other
units
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
type
group of components having similar design features and the similarity of whose manufacturing
techniques enables them to be grouped together either for qualification approval or for quality
conformance inspection
They are generally covered by a single detail specification
NOTE Components described in several detail specifications, may, in some cases, be considered as belonging to
the same type but they are generally covered by a single detail specification.
—————————
1
“DB” refers to the IEC on-line database.

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60738-1  IEC:2006+A1:2009 – 9 –
3.2
style
variation within a type having specific nominal dimensions and characteristics
3.3
thermistor
thermally sensitive semiconducting resistor which exhibits a significant change in electrical
resistance with a change in body temperature
3.4
positive temperature coefficient thermistor
thermistor, the resistance of which increases with its increasing temperature throughout the
useful part of its characteristic
3.5
positive step-function temperature coefficient thermistor
PTC
thermistor which shows a step-like increase in its resistance when the increasing temperature
reaches a specific value
A PTC thermistor will show secondary effects which are to be taken into account
3.6
zero-power resistance
R
T
value of the resistance of a PTC thermistor, at a given temperature, under conditions such
that the change in resistance due to the internal generation of heat is negligible with respect
to the total error of measurement
NOTE Any resistance value of a PTC thermistor is dependent on the value and the mode of the applied voltage
(a.c. or d.c.) and, when an a.c. source is used, on the frequency (see 3.8 and 3.9).
3.7
nominal zero-power resistance
R
n
d.c. resistance value of a thermistor measured at a specified temperature, preferably at 25 °C,
with a power dissipation low enough that any further decrease in power will result only in a
negligible change in resistance. Zero-power resist
...