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

IEC 60539-2:2019 is available as IEC 60539-2:2019 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.IEC 60539-2:2019 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.
This edition includes the following significant technical changes with respect to the previous edition:
a) revision for the structure in accordance with ISO/IEC Directives, Part 2:2016 (seventh edition) to the extent practicable, and for harmonizing with IEC 60539-1:2016;
b) the upper category temperatures of 175 °C, 200 °C, 250 °C, 315 °C, 400 °C in Table 1 have been added;
c) the dimensions of 0402M in Annex A have been added.

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

IEC 60539-2:2019 est disponible sous forme de IEC 60539-2:2019 RLV qui contient la Norme internationale et sa version Redline, illustrant les modifications du contenu technique depuis l'édition précédente.L'IEC 60539-2:2019 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 brasure et sont destinées à être montées directement sur des substrats pour circuits hybrides ou sur des cartes imprimées.
La présente édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) révision de la structure conformément aux directives ISO/IEC, Partie 2:2016 (septième édition), dans la mesure du possible, et pour l'harmonisation avec l'IEC 60539-1:2016;
b) les températures maximales de catégorie 175 °C, 200 °C, 250 °C, 315 °C, 400 °C ont été ajoutées dans le Tableau 1;
c) les dimensions de 0402M à l'Annexe A ont été ajoutées.

General Information

Status
Published
Publication Date
18-Jul-2019
Current Stage
PPUB - Publication issued
Completion Date
19-Jul-2019
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IEC 60539-2
Edition 2.0 2019-07
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
IEC 60539-2:2019-07(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 60539-2
Edition 2.0 2019-07
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
INTERNATIONALE
ICS 31.040.30 ISBN 978-2-8322-7098-1

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 60539-2:2019  IEC 2019
CONTENTS

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

1 Scope .............................................................................................................................. 6

2 Normative references ...................................................................................................... 6

3 Terms and definitions ...................................................................................................... 6

4 Information to be given in a detail specification ................................................................ 7

4.1 General ................................................................................................................... 7

4.2 Outline drawing and dimensions ............................................................................. 7

4.3 Mounting ................................................................................................................. 7

4.4 Ratings and characteristics ..................................................................................... 7

4.4.1 Particular characteristics ................................................................................. 7

4.4.2 Marking ........................................................................................................... 7

5 Preferred ratings and characteristics ............................................................................... 7

5.1 Tolerances on rated zero-power resistance ............................................................. 7

5.2 Climatic categories ................................................................................................. 8

6 Quality assessment procedures ....................................................................................... 8

7 Test and measurement procedures .................................................................................. 8

7.1 Mounting ................................................................................................................. 8

7.2 Drying and recovery ................................................................................................ 8

7.2.1 Drying .............................................................................................................. 8

7.2.2 Recovery ......................................................................................................... 8

7.3 Visual examination and check of dimensions .......................................................... 8

7.3.1 Visual examination .......................................................................................... 8

7.3.2 Requirements .................................................................................................. 9

7.3.3 Marking ......................................................................................................... 10

7.3.4 Dimensions .................................................................................................... 11

7.4 Electrical tests ...................................................................................................... 11

7.4.1 Zero-power resistance ................................................................................... 11

7.4.2 B-value or resistance ratio ............................................................................. 11

7.4.3 Resistance/temperature characteristic ........................................................... 11

7.5 Thermal tests ........................................................................................................ 12

7.5.1 Dissipation factor (δ) ...................................................................................... 12

7.5.2 Thermal time constant by cooling after self-heating (τ ) ................................. 12

7.6 Resistance to soldering heat ................................................................................. 12

7.6.1 General ......................................................................................................... 12

7.6.2 Initial measurement ....................................................................................... 12

7.6.3 Test conditions .............................................................................................. 12

7.6.4 Recovery ....................................................................................................... 12

7.6.5 Final inspection, measurements and requirements......................................... 12

7.7 Solderability .......................................................................................................... 13

7.7.1 General ......................................................................................................... 13

7.7.2 Test conditions .............................................................................................. 13

7.7.3 Recovery ....................................................................................................... 13

7.7.4 Final inspection, measurements and requirements......................................... 13

7.8 Rapid change of temperature ................................................................................ 13

7.9 Thermal shock ...................................................................................................... 13

---------------------- Page: 4 ----------------------
IEC 60539-2:2019  IEC 2019 – 3 –

7.10 Damp heat, steady state ....................................................................................... 14

7.11 Endurance ............................................................................................................ 14

7.11.1 Endurance at T and P ............................................................................. 14

3 max

7.11.2 Endurance at upper category temperature ..................................................... 15

7.12 Shear (adhesion) test ............................................................................................ 15

7.13 Substrate bending test .......................................................................................... 15

7.14 Component solvent resistance .............................................................................. 15

7.15 Solvent resistance of marking ............................................................................... 15

Annex A (normative) Guide for the specification and coding of dimensions of surface

mount negative temperature coefficient thermistors .............................................................. 16

Annex B (normative) Quality assessment procedure ............................................................ 17

B.1 Primary stage of manufacture ............................................................................... 17

B.2 Structurally similar components ............................................................................ 17

B.3 Qualification approval procedures ......................................................................... 17

B.4 Quality conformance inspection ............................................................................ 17

B.4.1 General ......................................................................................................... 17

B.4.2 Qualification approval on the basis of the fixed sample size procedure .......... 17

B.5 Quality conformance inspection ............................................................................ 19

B.5.1 Formation of inspection lots ........................................................................... 19

B.5.2 Test schedule ................................................................................................ 20

B.5.3 Delayed delivery ............................................................................................ 20

B.5.4 Assessment level ........................................................................................... 20

Figure 1 – Fault: fissure or defect ........................................................................................... 9

Figure 2 – Fault: crack ............................................................................................................ 9

Figure 3 – Separation or delamination .................................................................................... 9

Figure 4 – Exposed electrodes .............................................................................................. 10

Figure 5 – Principal faces ..................................................................................................... 10

Figure 6 – Principal terminations – Gull wing ........................................................................ 11

Figure 7 – Principal terminations – Round termination .......................................................... 11

Figure A.1 – Dimensioning of surface mount thermistors ....................................................... 16

Table 1 – Upper and lower category temperatures and duration of the damp heat test ............ 8

Table A.1 – Dimensions ........................................................................................................ 16

Table B.1 – Fixed sample size test schedule for qualification approval of surface mount

negative temperature coefficient thermistors Assessment level EZ ....................................... 19

Table B.2 – Lot-by-lot inspection ........................................................................................... 20

Table B.3 – Periodic test ....................................................................................................... 21

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– 4 – IEC 60539-2:2019  IEC 2019
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

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2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international

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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.

International Standard IEC 60539-2 has been prepared by IEC technical committee 40:

Capacitors and resistors for electronic equipment.

This second edition cancels and replaces the first edition published in 2003 and Amendment

1:2010. This edition constitutes a technical revision.

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

edition:

a) revision for the structure in accordance with ISO/IEC Directives, Part 2:2016 (seventh

edition) to the extent practicable, and for harmonizing with IEC 60539-1:2016;

b) the upper category temperatures of 175 °C, 200 °C, 250 °C, 315 °C, 400 °C in Table 1

have been added;
c) the dimensions of 0402M in Annex A have been added.
---------------------- Page: 6 ----------------------
IEC 60539-2:2019  IEC 2019 – 5 –
The text of this International Standard is based on the following documents:
FDIS Report on voting
40/2672/FDIS 40/2680/RVD

Full information on the voting for the approval of this International Standard can be found in

the report on voting indicated in the above table.

This document has been drafted in accordance with the ISO/IEC Directives, Part 2.

A list of all parts in the IEC 60539 series, published under the general title Directly heated

negative temperature coefficient thermistors, can be found on the IEC website.

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

stability date indicated on the IEC website under "http://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.

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.
---------------------- Page: 7 ----------------------
– 6 – IEC 60539-2:2019  IEC 2019
DIRECTLY HEATED NEGATIVE TEMPERATURE
COEFFICIENT THERMISTORS –
Part 2: Sectional specification –
Surface mount negative temperature coefficient thermistors
1 Scope

This part of IEC 60539 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.
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.
IEC 60068-2-2:2007, Environmental testing – Part 2-2: Tests – Tests B: Dry heat

IEC 60068-2-14:2009, Environmental testing – Part 2-14: Tests – Test N: Change of

temperature

IEC 60068-2-58:2015, 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 60068-2-58:2015/AMD1:2017

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

state

IEC 60539-1:2016, Directly heated negative temperature coefficient thermistors – Part 1:

Generic specification

IEC 61193-2:2007, Quality assessment systems – Part 2: Selection and use of sampling plans

for inspection of electronic components and packages
3 Terms and definitions

For the purposes of this document, the terms and definitions given in IEC 60539-1 apply.

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
---------------------- Page: 8 ----------------------
IEC 60539-2:2019  IEC 2019 – 7 –
4 Information to be given in a detail specification
4.1 General

Detail specifications shall be derived from the relevant blank detail specification.

Detail specifications shall not specify requirements inferior to those of the generic, sectional

or blank detail specification. When more severe requirements are included, they shall be

listed in 1.9 of the detail specification and indicated in the test schedules, for example, by an

asterisk.
The information given in 4.2 may for convenience, be presented in tabular form.

The information in 4.2 to 4.4 shall be given in each detail specification and the values quoted

shall preferably be selected from those given in the appropriate clause of this sectional

specification.
4.2 Outline drawing and dimensions

There shall be an illustration of the thermistor as an aid to easy recognition and for

comparison with others. Dimensions and their associated tolerances, which affect inter-

changeability and mounting, shall be given in the detail specification. All dimensions shall

preferably be stated in millimetres; however, when the original dimensions are given in inches,

the converted metric dimensions in millimetres shall be added.

Normally, the numerical values shall be given for the length, width and height of the body.

When necessary, for example when a number of items are covered by a detail specification,

the dimensions and their associated tolerances shall be placed in a table below the drawing.

When the configuration is other than described above, the detail specification shall state such

dimensional information as will adequately describe the thermistor.
4.3 Mounting

The detail specification shall give guidance on methods of mounting for normal use. Mounting

for test and measurement purposes (when required) shall be in accordance with
IEC 60539-1:2016, 5.4.
4.4 Ratings and characteristics
4.4.1 Particular characteristics

Additional characteristics may be listed when they are considered necessary to specify the

component adequately for design and application purposes.
4.4.2 Marking
See IEC 60539-1:2016, 4.3.
5 Preferred ratings and characteristics
5.1 Tolerances on rated zero-power resistance
Preferred values of tolerances on zero-power resistance are:
±0,5 %, ±1 %, ±2 %, ±3 %, ±5 %, ±10 %.
---------------------- Page: 9 ----------------------
– 8 – IEC 60539-2:2019  IEC 2019
5.2 Climatic categories

The upper and lower category temperatures and the duration of the damp-heat steady-state

test shall be selected from Table 1.

Table 1 – Upper and lower category temperatures and duration of the damp heat test

Lower category temperature
−55, −40, −25, −10, −5, +5
Upper category temperature
70, 85, 100, 105, 125, 150, 155, 175, 200, 250, 315, 400
Damp heat, steady state
21, 42, 56
days
The detail specification shall prescribe the appropriate category.
6 Quality assessment procedures
See Annex B.
7 Test and measurement procedures
7.1 Mounting
See IEC 60539-1:2016, 5.4.
7.2 Drying and recovery
7.2.1 Drying

Where drying is called for in this specification, the thermistor shall be conditioned as follows.

For 96 h ± 4 h in an oven at a temperature of 100 °C ± 5 °C, the thermistor shall then be

allowed to cool in a desiccator using a suitable desiccant, such as activated alumina or

silicagel, and shall be kept therein from the time of removal from the oven to the beginning of

the specified tests.
7.2.2 Recovery

Unless otherwise specified, recovery shall take place under the standard atmospheric

conditions for testing (see IEC 60539-1:2016, 5.3.2).
7.3 Visual examination and check of dimensions
7.3.1 Visual examination

Visual examination shall be carried out with suitable equipment with approximately 10×

magnification and lighting appropriate to the specimen under test and the quality level

required.

The operator should have facilities available for incident or transmitted illumination as well as

an appropriate measuring facility.
---------------------- Page: 10 ----------------------
IEC 60539-2:2019  IEC 2019 – 9 –
7.3.2 Requirements
7.3.2.1 General

Quantitative values for the requirements below may be given in the detail or in the

manufacturer’s specification.
The thermistor shall conform to the following requirements.
7.3.2.2 Requirements for ceramic
Requirements for the ceramic are as follows:
1) Bulk type

a) It shall be free of fissures of coating glass longer than 25 % of dimension L (see

Annex A, Figure A.1) and defects of glass coating on each face greater than 10 % of

the area of that face (see Figure 1).
NOTE Fissure on a corner and defect on one side.
Figure 1 – Fault: fissure or defect

b) It shall be free of cracks, except for small damage on the surface, which does not

impair the performance of the thermistor (see Figure 2).
NOTE Crack on one side or extending from one face to another over a corner.
Figure 2 – Fault: crack
2) Layered type

a) It shall not exhibit visible separation or delamination between the layers of the

thermistor (see Figure 3). Excluding the case when a few things which do not influence

a characteristic of the surface implementation form an NTC thermistor, the surface

shall not be cracked (see Figure 3).
Figure 3 – Separation or delamination

b) It shall not exhibit exposed electrodes between the two terminations (see Figure 4).

It shall not exhibit any visible detachment of the metallized terminations nor any

exposed electrodes (see Figure 4).
---------------------- Page: 11 ----------------------
– 10 – IEC 60539-2:2019  IEC 2019
Figure 4 – Exposed electrodes
7.3.2.3 Requirements for the metallization
Requirements for the metallization are as follows:
The principal faces are those noted A, B, C, D and E (see Figure 5).
a) Termination on bottom is the principal face noted C.
b) Terminations on 3 sides are the principal faces noted A, B and C.
c) Terminations on 5 sides a
...

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