SIST EN 61643-321:2002

SLOVENSKI STANDARD
SIST EN 61643-321:2002
01-november-2002
6HVWDYQLGHOL]DQL]NRQDSHWRVWQHQDSUDYH]D]DãþLWRSUHGSUHQDSHWRVWQLPLXGDUL
GHO6SHFLILNDFLMH]DGLRGHVSOD]RYLWLPSUHERMHP$%',(&
Components for low-voltage surge protective devices -- Part 321: Specifications for
Avalanche Breakdown Diode (ABD)
Bauelemente für Überspannungsschutzgeräte für Niederspannung -- Teil 321:
Festlegungen für Avalanche-Dioden (ABD)
Composants pour parafoudres basse tension -- Partie 321: Spécifications pour les
diodes à avalanche (ABD)
Ta slovenski standard je istoveten z: EN 61643-321:2002
ICS:
29.120.50 9DURYDONHLQGUXJD Fuses and other overcurrent
PHGWRNRYQD]DãþLWD protection devices
31.080.10 Diode Diodes
SIST EN 61643-321:2002 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 61643-321:2002

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SIST EN 61643-321:2002
EUROPEAN STANDARD EN 61643-321
NORME EUROPÉENNE
EUROPÄISCHE NORM February 2002
ICS 31.080.10
English version
Components for low-voltage surge protective devices
Part 321: Specifications for avalanche breakdown diode (ABD)
(IEC 61643-321:2001)
Composants pour parafoudres Bauelemente für Überspannungs-
basse tension schutzgeräte für Niederspannung
Partie 321: Spécifications pour Teil 321: Festlegungen für
les diodes à avalanche (ABD) Avalanche-Dioden (ABD)
(CEI 61643-321:2001) (IEC 61643-321:2001)
This European Standard was approved by CENELEC on 2002-02-01. CENELEC members are bound to
comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and
notified to the Central Secretariat has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic,
Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands,
Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2002 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 61643-321:2002 E

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SIST EN 61643-321:2002
EN 61643-321:2002 - 2 -
Foreword
The text of document 37B/59/FDIS, future edition 1 of IEC 61643-321, prepared by SC 37B, Specific
components for surge arresters and surge protective devices, of IEC TC 37, Surge arresters, was
submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 61643-321 on
2002-02-01.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2002-11-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2005-02-01
Annexes designated "normative" are part of the body of the standard.
In this standard, annex ZA is normative.
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 61643-321:2001 was approved by CENELEC as a
European Standard without any modification.
__________

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SIST EN 61643-321:2002
- 3 - EN 61643-321:2002
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
This European Standard incorporates by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text and the
publications are listed hereafter. For dated references, subsequent amendments to or revisions of any
of these publications apply to this European Standard only when incorporated in it by amendment or
revision. For undated references the latest edition of the publication referred to applies (including
amendments).
NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
Publication Year Title EN/HD Year
IEC 60068 Series Environmental testing EN 60068 Series
IEC 60364 Series Electrical installations of buildings HD 384 S2 Series
(mod)
IEC 60364-3 1993 Electrical installations of buildings HD 384.3 S2 1995
(mod) Part 3: Assessment of general
characteristics
IEC 60721 Series Classification of environmental EN 60721 Series
conditions
IEC 60747-2 2000 Semiconductor devices - Discrete--
devices and integrated circuits
Part 2: Rectifier diodes
IEC 60749 1996 Semiconductor devices - Mechanical EN 60749 1999
and climatic test methods

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SIST EN 61643-321:2002

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SIST EN 61643-321:2002
NORME CEI
INTERNATIONALE IEC
61643-321
INTERNATIONAL
Première édition
STANDARD
First edition
2001-12
Composants pour parafoudres
basse tension –
Partie 321:
Spécifications pour les diodes
à avalanche (ABD)
Components for low-voltage surge
protective devices –
Part 321:
Specifications for avalanche
breakdown diode (ABD)
 IEC 2001 Droits de reproduction réservés  Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in
utilisée sous quelque forme que ce soit et par aucun procédé, any form or by any means, electronic or mechanical,
électronique ou mécanique, y compris la photocopie et les including photocopying and microfilm, without permission in
microfilms, sans l'accord écrit de l'éditeur. writing from the publisher.
International Electrotechnical Commission 3, rue de Varembé Geneva, Switzerland
Telefax: +41 22 919 0300 e-mail: inmail@iec.ch IEC web site http://www.iec.ch
CODE PRIX
Commission Electrotechnique Internationale
P
PRICE CODE
International Electrotechnical Commission
Pour prix, voir catalogue en vigueur
For price, see current catalogue

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SIST EN 61643-321:2002
61643-321 © IEC:2001 – 3 –
CONTENTS
FOREWORD.3
1 Scope.7
2 Normative references .7
3 Definitions and symbols.7
4 Basic function and description for ABDs .13
5 Service conditions .17
6 Standard test methods and procedures.17
6.1 Standard design test criteria.17
6.2 Test conditions .17
6.3 Clamping voltage V (see figure 2).19
C
6.4 Rated peak impulse current I (see figure 2) .19
PPM
6.5 Maximum working voltage V and maximum working r.m.s. voltage V
WM WMrms
(see figure 3).19
6.6 Stand-by current I (see figure 3) .21
D
6.7 Breakdown (avalanche) voltage V (see figure 4) .21
BR
6.8 Capacitance C .23
j
6.9 Rated peak impulse power dissipation P .23
PPM
6.10 Rated forward surge current I (see figure 1c).23
FSM
6.11 Forward voltage V .23
FS
6.12 Temperature coefficient of breakdown voltage αV .25
BR
6.13 Temperature derating (see figure 5) .25
6.14 Thermal resistance R or R or R .25
thJA thJC thJL
6.15 Transient thermal impedance Z or Z or Z .25
thJA thJC thJL
6.16 Rated average power dissipation P .27
MAV
6.17 Peak overshoot voltage V (see figure 7) .27
OS
6.18 Overshoot duration (see figure 7) .27
6.19 Response time (see figure 7).27
7 Fault and failure modes .31
7.1 Degradation fault mode .31
7.2 Short-circuit failure mode.31
7.3 Open-circuit failure mode .31
7.4 "Fail-safe" operation .31
Figure 1 – Structure, bias condition and V-I characteristics for a unidirectional ABD .13
Figure 2 – Test circuit for clamping voltage V , peak impulse current I , and rated
C PP
forward surge current I .19
FSM
Figure 3 – Test circuit for verifying maximum working voltage V stand-by current I
WM D
and maximum working r.m.s. voltage V .21
WMrms
Figure 4 – Test circuit for verifying breakdown (avalanche) voltage V .21
BR
Figure 5 – Test circuit for verifying forward voltage V .23
FS
Figure 6 – Derating curve for ABD components.27
Figure 7 – Graph illustrating voltage overshoot, response time and overshoot duration.29
Figure 8 – Impulse current waveform .29

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SIST EN 61643-321:2002
61643-321 © IEC:2001 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
COMPONENTS FOR LOW-VOLTAGE SURGE PROTECTIVE DEVICES –
Part 321: Specifications for avalanche breakdown diode (ABD)
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the 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, the IEC publishes International Standards. 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. The 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 the 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 National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61643-321 has been prepared by subcommittee 37B: Specific
components for surge arresters and surge protective devices, of IEC technical committee 37:
Surge arresters.
The text of this standard is based on the following documents:
FDIS Report on voting
37B/59/FDIS 37B/62/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 3.
The committee has decided that the contents of this publication will remain unchanged
until 2005. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.

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SIST EN 61643-321:2002
61643-321 © IEC:2001 – 7 –
COMPONENTS FOR LOW-VOLTAGE SURGE PROTECTIVE DEVICES –
Part 321: Specifications for avalanche breakdown diode (ABD)
1 Scope
This part of IEC 61643 is applicable to avalanche breakdown diodes (ABDs) which represent
one type of surge protective device component (hereinafter referred to as SPDC) used in the
design and construction of surge protective devices connected to low-voltage power
distribution systems, transmission, and signalling networks. Test specifications in this
standard are for single ABDs consisting of two terminals. However, multiple ABDs may be
assembled within a single package defined as a diode array. Each diode within the array can
be tested to this specification.
This standard contains a series of test criteria for determining the electrical characteristics of
the ABD. From the standard test methods described herein, the performance characteristics
and ratings of the ABD can be verified or established for specific packaged designs.
2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this part of IEC 61643. For dated references, subsequent amend-
ments to, or revisions of, any of these publications do not apply. However, parties to
agreements based on this part of IEC 61643 are encouraged to investigate the possibility of
applying the most recent editions of the normative documents indicated below. For undated
references, the latest edition of the normative document referred to applies. Members of IEC
and ISO maintain registers of currently valid International Standards.
IEC 60068 (all parts), Environmental testing
IEC 60364 (all parts), Electrical installations of buildings
IEC 60364-3:1993, Electrical installations of buildings – Part 3: Assessment of general
characteristics
IEC 60721 (all parts), Classification of environmental conditions
IEC 60747-2:2000, Semiconductor devices – Discrete devices and integrated circuits – Part 2:
Rectifier diodes
IEC 60749:1996, Semiconductor devices – Mechanical and climatic test methods
3 Definitions and symbols
For the purpose of this part of IEC 61643, the following definitions and symbols apply.
NOTE These definitions apply to one type of SPDC known as an ABD, having both symmetrical and asymmetrical
voltage-current (V-I) characteristics. Such definitions are for a unidirectional element (see figure 1). If the ABD is
considered bidirectional, definitions in the third quadrant will apply in both directions of the V-I characteristic curve.
3.1
avalanche breakdown diode ABD
component intended to limit transient voltages and divert surge currents. This is a two-
terminal diode that may be packaged with multiple elements having a common terminal

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SIST EN 61643-321:2002
61643-321 © IEC:2001 – 9 –
3.2
clamping voltage V
C
peak voltage measured across the ABD during the application of a peak impulse current I
PP
for a specified waveform
NOTE Due to the thermal, reactive, or other effects, peak voltage and peak pulse current are not necessarily
coincident in time. Also shown as V .
CL
3.3
rated peak impulse current I
PPM
rated maximum value of peak impulse current I that may be applied without causing diode
PP
failure
NOTE The impulse waveshape used for diode characterization is 10/1 000 μs unless otherwise specified.
3.4
maximum working voltage (maximum d.c. voltage) V
WM
maximum peak working or d.c. voltage which may be continuously applied to the ABD without
degradation or damaging effects. For a.c. applied voltages, the maximum working r.m.s.
voltage is V
WMrms
NOTE  It is also shown as V (rated maximum) and known as rated stand-off voltage.
RM
3.5
stand-by current I
D
maximum current that flows through the ABD at maximum working voltage for a specified
temperature
NOTE Also shown as I for reverse leakage current.
R
3.6
breakdown (avalanche) voltage V
BR
voltage measured across the ABD at a specified pulsed d.c. current I (or I ) on the V-I
T BR
characteristics curve at, or near, the place where the avalanche occurs
3.7
capacitance C
j
capacitance between two terminals of the ABD measured at a specific frequency and bias
NOTE Also shown as C.
3.8
rated peak impulse power dissipation P
PPM
peak pulse power dissipation resulting from the product of rated peak impulse current I
PPM
and clamping voltage V
C
P = I × V
PPM PPM C
NOTE Also shown as P .
P
3.9
rated forward surge current I
FSM
maximum peak current for an 8,3 ms or 10 ms half-sine wave without causing device failure.
(This definition applies to unidirectional ABDs only.)

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SIST EN 61643-321:2002
61643-321 © IEC:2001 – 11 –
3.10
forward voltage V
FS
peak voltage measured across the ABD for a specified forward surge current I . (This defi-
FS
nition applies to unidirectional ABDs only.)
NOTE Also shown as V .
F
3.11
temperature coefficient of breakdown voltage ααααV
BR
ratio of the change in breakdown voltage V to changes in temperature
BR
NOTE Expressed as either millivolts per degree Kelvin or per cent per degree Kelvin (mV/K or %/K).
3.12
temperature derating
derating above a specified base temperature for either peak impulse current or peak impulse
power
NOTE Expressed in percentage of the current or power.
3.13
thermal resistance R , R , R
thJA thJC thJL
junction to ambient, case or lead terminal temperature rise per unit input of applied power
expressed as degrees Kelvin per watt (K/W)
3.14
transient thermal impedance Z , Z , Z
thJA thJC thJL
change in the difference between the virtual junction temperature and the temperature of a
specific reference point or region (ambient, case or lead) at the end of a time interval. This
change is divided by the step function change in power dissipation at the beginning of the
same time interval which causes the change of temperature difference.
NOTE Thermal resistance is expressed as degrees Kelvin per watt (K/W).
3.15
rated average power dissipation P
M(AV)
rated average power dissipation in the device due to repetitive pulses at a specified current
and temperature without causing device failure
3.16
peak overshoot voltage V
OS
excess voltage above the clamping voltage V of the device for a given current that occurs
C
when current waves of less than, or equal to, 10 μs virtual front duration are applied
NOTE This value may be expressed as a percentage of the clamping voltage V for a 10/1 000 μs current wave.
C
3.17
pulsed d.c. test current I
T
test current for measurement of the breakdown voltage V . This is defined by t
...