EN 61709:1998
(Main)Electronic components - Reliability - Reference conditions for failure rates and stress models for conversion
Electronic components - Reliability - Reference conditions for failure rates and stress models for conversion
Gives guidance on the use of failure rate data for the reliability prediction of components in electronic equipment. Reference conditions for failure rate data are specified, so that data from different sources can be compared. The reference conditions adopted are typical of the majority of applications of components in equipment (e.g. telecommunication use, data processing). In this standard it is assumed that the failure rate used under reference conditions is specific to the component i.e. it includes the effect of complexity, technology of the casing, dependence on manufacturers and the manufacturing process, etc.
Bauelemente der Elektronik - Zuverlässigkeit - Referenzbedingungen für Ausfallraten und Beanspruchungsmodelle zur Umrechnung
Composants électroniques - Fiabilité - Conditions de référence pour les taux de défaillance et modèles d'influence des contraintes pour la conversion
Donne des recommandations pour l'emploi de taux de défaillance destinés à des prévisions de fiabilité de composants d'équipements électroniques. Il est défini des conditions de référence pour les taux de défaillance de façon à permettre des comparaisons de données de taux de défaillance ayant différentes origines. Les conditions de référence choisies sont représentatives de la plupart des applications des composants dans les équipements (par exemple les télécommunications, les calculateurs). On suppose dans cette norme que le taux de défaillances donné dans les conditions de référence est représentatif du composant, c'est-à-dire ui'il tient compte des effets de la complexité, du type de boitier, de l'influence des fabricants et des procédés de fabrication etc.
Electronic components - Reliability - Reference conditions for failure rates and stress models for conversion (IEC 61709:1996)
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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Electronic components - Reliability - Reference conditions for failure rates and stress models for conversion (IEC 61709:1996)Bauelemente der Elektronik - Zuverlässigkeit - Referenzbedingungen für Ausfallraten und Beanspruchungsmodelle zur UmrechnungComposants électroniques - Fiabilité - Conditions de référence pour les taux de défaillance et modèles d'influence des contraintes pour la conversionElectronic components - Reliability - Reference conditions for failure rates and stress models for conversion31.020Elektronske komponente na splošnoElectronic components in general21.020Characteristics and design of machines, apparatus, equipmentICS:Ta slovenski standard je istoveten z:EN 61709:1998SIST EN 61709:2002en01-september-2002SIST EN 61709:2002SLOVENSKI
STANDARD
NORMEINTERNATIONALECEIIECINTERNATIONALSTANDARD1709Première éditionFirst edition1996-10Ó CEI 1996
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catalogueXComposants électroniques
–Fiabilité –Conditions de référence pour les taux dedéfaillance et modèles d’influence descontraintes pour la conversionElectronic components –Reliability –Reference conditions for failure ratesand stress models for conversionSIST EN 61709:2002
1709 ã IEC:1996- 3 -CONTENTSPageFOREWORD.5INTRODUCTION.7Clause1 Scope.92 Normative references.93 Definitions.94 Symbols.115 Reference conditions.156 Generic stress models.217 Specific stress models.27AnnexesA
Limitations of reliability models and predictions.67B Examples.77C Bibliography.83SIST EN 61709:2002
1709 ã IEC:1996- 5 -INTERNATIONAL ELECTROTECHNICAL COMMISSION_________ELECTRONIC COMPONENTS -Reliability -Reference conditions for failure ratesand stress models for conversionFOREWORD1)The IEC (International Electrotechnical Commission) is a worldwide organization for standardizationcomprising all national electrotechnical committees (IEC National Committees). The object of the IEC is topromote international co-operation on all questions concerning standardization in the electrical and electronicfields. To this end and in addition to other activities, the IEC publishes International Standards. Theirpreparation is entrusted to technical committees; any IEC National Committee interested in the subject dealtwith may participate in this preparatory work. International, governmental and non-governmental organizationsliaising with the IEC also participate in this preparation. The IEC collaborates closely with the InternationalOrganization for Standardization (ISO) in accordance with conditions determined by agreement between thetwo organizations.2)The formal decisions or agreements of the IEC on technical matters, express as nearly as possible, aninternational consensus of opinion on the relevant subjects since each technical committee has representationfrom all interested National Committees.3)The documents produced have the form of recommendations for international use and are published in theform of standards, technical reports or guides and they are accepted by the National Committees in thatsense.4)In order to promote international unification, IEC National Committees undertake to apply IEC InternationalStandards transparently to the maximum extent possible in their national and regional standards. Anydivergence between the IEC Standard and the corresponding national or regional standard shall be clearlyindicated in the latter.5)The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for anyequipment 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 thesubject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights.International Standard IEC 1709 has been prepared by IEC technical committee 56:Dependability.The text of this standard is based on the following documents:FDISReport on voting56/494/FDIS56/534/RVDFull information on the voting for the approval of this standard can be found in the report onvoting indicated in the above table.Annexes A, B and C are for information only.SIST EN 61709:2002
1709 ã IEC:1996- 7 -INTRODUCTIONFailure rate data are useful in the design phase of electronic equipment. They can be used toidentify potential reliability problems, the planning of logistic support strategies and theevaluation of designs and reliability predictions. Predictions are essentially probabilitystatements which are based on the failure rates of electronic components. These predictionsshould be carried out before hardware realization and/or the procurement process of anequipment.Unsubstantiated failure rate data used in reliability predictions can cause inaccuracies. Theseinaccuracies can be reduced by post processing supplied failure data to remove information onreplacements that are not real failures. Failure rate data should include knowledge of the failurecriteria and the mechanical and electrical stresses which have resulted in the componentfailure. This International Standard serves as a guide to describe reference conditions for whichfield failure rates should be stated. This then allows, by the use of stress models, extrapolationto other operating conditions. Some of the limitations of the models are outlined in annex A. Itis not intended to replace other valid handbooks.The reference conditions adopted are typical of the majority of applications of components inequipment (e.g. telecommunication use, data processing). In this standard it is assumed thatthe failure rate used under reference conditions is specific to the component i.e. it includes theeffect of complexity, technology of the casing, dependence on manufacturers and themanufacturing process, etc.The component failure rates to be used with this standard are to be determined based uponagreement between the component manufacturer and the component user, using one or moreof the following sources: equipment manufacturer data book, equipment user data book,component manufacturer data book or data from an independent third body. Sources should bethe latest available that are applicable to the product and its specific use conditions. Ideally,failure rate data should be obtained from the field.The stress factors for different conditions are specified in this standard. They are typical valuesfor the individual component classes from various manufacturers. When actual conditions ofuse are in close agreement with reference conditions, then as a first approximation the agreedcomponent failure rates can be used. The stress factors should be used, when they are knownto be correct or as an approximation, if nothing else is known. Where they are applied, their useshould be clearly stated. If other factors are known to be correct, they should be stated andused.SIST EN 61709:2002
1709 ã IEC:1996- 9 -ELECTRONIC COMPONENTS -Reliability -Reference conditions for failure ratesand stress models for conversion1 ScopeThis International Standard gives guidance on the use of failure rate data for the reliabilityprediction of components in electronic equipment. Reference conditions for failure rate data arespecified, so that data from different sources can be compared on a uniform basis. If failurerate data are given in accordance with this standard then no additional information on thespecified conditions is required.The stress models described in this standard should be used as a basis for conversion of thefailure rate data at reference conditions to the actual operating conditions. Conversion of failurerate data are only permissible within the specified functional limits of the components (seeannex A).2 Normative referencesThe following normative documents contain provisions which, through reference in this text,constitute provisions of this International Standard. At the time of publication, the editionsindicated were valid. All normative documents are subject to revision, and parties toagreements based on this International Standard are encouraged to investigate the possibilityof applying the most recent editions of the normative documents indicated below. Members ofIEC and ISO maintain registers of currently valid International Standards.IEC 50(191): 1990, International Electrotechnical Vocabulary (IEV) -
Chapter 191: Depend-ability and quality of serviceIEC 721-3-3: 1994,
Classification of environmental conditions - Part 3: Classification of groupsof environmental parameters and their severities - Section 3: Stationary use at weather-protected locations3 DefinitionsFor the purpose of this International Standard, the following definitions apply:3.1failure: Termination of the ability of an item to perform a required function. [IEV 191-04-01]3.2failure rate: Limit, if this exists, of the ratio of the conditional probability that the instant oftime, T, of a failure of an item falls within a given time interval, (t, t + DT) and the length of thisinterval, DT, when DT tends to zero, given that the item is in an up state at the beginning of thetime interval. [IEV 191-12-02].The characteristic preferred for reliability data of electronic components is the failure rate asdefined in IEV 191-12-02 (see also A.3).NOTE
In this definition T may also denote the time to failure or the time to first failure, as the case may be.SIST EN 61709:2002
1709 ã IEC:1996- 11 -3.3mean failure rate: Mean of the failure rate over a given time interval. [IEV 191-12-03,modified]3.4reference conditions: Reference conditions selected so as to correspond to the majorityof applications of components in equipment.3.5reference failure rate: Failure rate stated under the reference conditions given in thisstandard.NOTE – Reference failure rates are not necessarily equal because of the unquantifiable nature of themanufacturing processes and the assembly stages of components into equipment. However, failure ratevalues are found in practice to have similarities from one analysis to another. It is therefore suggested thatthe use of reference failure rate values can provide comparative information between different componentcategories and act as a useful guide for reliability calculations.3.6
failure criterion: Condition for the presence of a failure.NOTE – The failure criterion will also depend on the application of the component.3.7operating mode: Operating mode states whether components are continuously stressedduring their operation. A distinction is made between continuous duty and intermittent duty.Continuous duty is defined as operation for a long duration with constant or changing loads(e.g. process controls, telephone switch).Intermittent duty is defined as operation with constant or changing loads during up state (e.g.numerical controls for machinery, road traffic signals).3.8
prediction: Process of computation used to obtain the predicted value(s) of a quantity.[IEV 191-16-01]NOTE – The term “prediction” may also be used to denote the predicted values of a quantity.4 SymbolsIn this standard, the following symbols are used:lfailure rate under operating conditionslreffailure rate under reference conditionspUvoltage dependence factorpIcurrent dependence factorpTtemperature dependence factorpESelectrical stress dependence factorpSswitching rate dependence factorqambambient temperature in degrees CelsiusTambambient temperature in kelvinsqamb,refreference ambient temperature in degrees CelsiusTamb,refreference ambient temperature in kelvinsqrefreference temperature in degrees CelsiusTrefreference temperature in kelvinsSIST EN 61709:2002
1709 ã IEC:1996- 13 -DTrefreference self-heating in degrees CelsiusDTactual self-heating in degrees Celsiusq1 in degrees Celsius:–for integrated circuits the reference virtual (equivalent) junctiontemperature*;–for discrete semiconductors and optoelectronic components the referencejunction temperature;–for resistors the average reference temperature of the resistor element;–for inductors the average reference temperature of the winding;–for capacitors the reference temperature of the capacitor;–for other electronic components the reference temperature of thecomponent.q2 in degrees Celsius:–for integrated circuits the actual virtual (equivalent) junction temperature;–for discrete semiconductors and optoelectronic components the actualjunction temperature;–for resistors the average actual resistor element temperature;–for inductors the average actual winding temperature;–for capacitors the actual capacitor temperature;–for other electronic components the actual ambient temperature.Uoperating voltageUrefreference voltageUratrated voltageIoperating currentIrefreference currentIratrated currentPoperating power dissipationPrefreference power dissipationPratrated power dissipationRththermal resistanceRth,ambthermal resistance (to the environment)_________* In IEC 747-1, the virtual temperature Tvj i
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