IEC 62421:2007

IEC 62421
Edition 1.0 2007-08
INTERNATIONAL
STANDARD
Electronics assembly technology – Electronic modules

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.

IEC Central Office
3, rue de Varembé
CH-1211 Geneva 20
Switzerland
Email: inmail@iec.ch
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It also gives information on projects, withdrawn and replaced publications.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: csc@iec.ch
Tel.: +41 22 919 02 11
Fax: +41 22 919 03 00
IEC 62421
Edition 1.0 2007-08
INTERNATIONAL
STANDARD
Electronics assembly technology – Electronic modules

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
P
ICS 31.190 ISBN 2-8318-9300-3
– 2 – 62421 © IEC:2007(E)
CONTENTS
FOREWORD.4

1 Scope and object.6
2 Normative references .6
3 Terms and definitions .7
4 Business model and interface between supplier and user .7
4.1 Business model (see Figure 1 and Figure 2).7
4.1.1 General .7
4.1.2 E-type business model .8
4.1.3 M-type business model.9
4.1.4 F-type business model.9
4.2 S-U interface (see Figure 1) .9
4.2.1 S-U interface –1 .9
4.2.2 S-U interface–2 .9
4.2.3 S-U interface–3 .9
4.3 Standardization areas .9
5 Preferred ratings .10
5.1 General .10
5.2 Preferred operating temperature range.11
5.3 Preferred rated voltage.11
6 Tests and measuring methods .11
6.1 Standard atmospheric conditions.11
6.1.1 Standard atmospheric conditions for testing .11
6.1.2 Referee conditions .11
6.1.3 Reference conditions.12
6.2 Electrical performance tests .12
6.2.1 General .12
6.2.2 Protection of electronic modules and test equipment .12
6.2.3 Accuracy of measurement .12
6.3 Mechanical performance tests .13
6.3.1 Robustness of terminations and integral mounting devices .13
6.3.2 Resistance to soldering heat .14
6.3.3 Solderability .14
6.3.4 Shock .14
6.3.5 Vibration (sinusoidal).14
6.3.6 Resistance to solvents.15
6.4 Climatic performance tests .15
6.4.1 Dry heat .15
6.4.2 Cold .15
6.4.3 Damp heat, steady state.16
6.4.4 Change of temperature.16

62421 © IEC:2007(E) – 3 –
Figure 1 – S-U interfaces in each business model.8
Figure 2 – Standardization areas in M-type and F-type business models .10

Table 1 – Preferred temperatures to be selected for temperature ranges (°C).11
Table 2 – Referee conditions .12
Table 3 – Application .14

– 4 – 62421 © IEC:2007(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
______________
ELECTRONICS ASSEMBLY TECHNOLOGY –
ELECTRONIC MODULES
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 Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
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 62421 has been prepared by IEC technical committee 91:
Electronics assembly technology.
The text of this standard is based on the following documents:
FDIS Report on voting
91/689/FDIS 91/722/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

62421 © IEC:2007(E) – 5 –
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result 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.
A bilingual version of this publication may be issued at a later date.

– 6 – 62421 © IEC:2007(E)
ELECTRONICS ASSEMBLY TECHNOLOGY –
ELECTRONIC MODULES
1 Scope and object
This International Standard provides a generic standard of electronic modules on which their
sectional standards are based.
This standard provides a definition, business model, interface between the trading partners,
and related areas of standardization of electronic modules. In addition a generic set of test
method is provided.
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 60068 (all parts), Environmental testing
IEC 60068-1:1988, Environmental testing – Part 1: General and guidance
IEC 60068-2-1: Environmental Testing – Part 2-1: Tests – Test 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 60068-2-14: Environmental testing – Part 2-14: Tests – Test N: Change of temperature
IEC 60068-2-20: Environmental testing – Part 2-20: Tests – Test T: Soldering
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 60068-2-45: Environmental testing – 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
ISO 3: Preferred numbers – Series of preferred numbers

62421 © IEC:2007(E) – 7 –
3 Terms and definitions
For the purposes of this document, the terms and definitions given in the IEC 60068 series, as
well as the following, apply.
3.1
electronic module
functional block which contains individual electronic elements and /or electronic packages, to
be used in a next level assembly
NOTE An individual module having an application-specific function, including electronic, optoelectronic,
mechanical or other elements. The module typically provides protection of its elements and packages to assure the
required level of reliability.
Electronic modules may be categorized by signa
...