1、Electronic Industries Alliance March 25,2002 SUBJECT: Standards Proposal No. 4900, Proposed New Standard “Use of Semiconductor Devices Outside Manufacturers Specified Temperature Ranges” (if approved, to be published as ANSVEIA-4900) BACKGROUND: The GEN APMC Avionics Process Management Committee aut
2、horized circulation of a letter ballot that was issued May 22, 2001 with the voting period ending June 22, 2001. Because of comments received, the letter ballot was re-circulated on August 1, 2001 with the voting period ending August 3 1, 2001. The document is now being circulated for Standards Prop
3、osal public Review comment. SP-4900 is herewith submitted for ANSI public review and other interested parties for comment as steps towards standardization. NOTE Please provide the following information whether voting or commenting via public review. Number each comment whether it is either editorial
4、 and/or technical. Company Name - Comment No. Type of Comment Reference Suggested Change Rationale for Technical Change - Technical or Editorial - Page No., Clause No., Line - Change From: . To: . Add:, Delete: FOR PURPOSE OF PUBLIC REVIEW: 2002 COMMENT PERIOD EXPIRES MAY 27, Prior to this date, you
5、 may forward your comments to the designated EN contact noted below. Following the expiration of the comment period, this Standards Proposal will be submitted to the EIA Technology Strategy OR; 2. Fax your comments, prior to the deadline, to: 703 907 7968. Include this form with your signature and u
6、pon manufacturers of military- specified devices as device sources. This assured the availability of semiconductor devices specified to operate over the temperature ranges required for electronic equipment in rugged applications. Many device manufacturers have exited the military market in recent ye
7、ars, resulting in decreased availability of devices specified to operate over wide temperature ranges. Following are some typical temperature ranges at which devices are marketed: I Military: I -55C to +125“C Automotive : -40C to +125“C -40C to +85“C Commercial: 0C to +70“C If there are no reasonabl
8、e or practical alternatives, then a potential response is for equipment manufacturers to use devices in temperature ranges that are wider than those specified by the device manufacturer. If properly documented and controlled, this practice may be used by electronic equipment manufacturers to meet th
9、e design goals of their equipment. This document prescribes practices and procedures to select semiconductor devices; to assess their capability to operate; and to assure their intended quality in the wider temperature ranges. It also prescribes the documentation of such usage. The intent of this do
10、cument is to describe processes for thermal uprating only. 1. Scope This document prescribes processes for using semiconductor devices in wider temperature ranges than those specified by the device manufacturer. It applies to any designer or manufacturer of equipment intended to operate under condit
11、ions that require semiconductor devices to function in temperature ranges beyond those for which the devices are marketed. This document is intended for applications in which only the performance of the device is an issue. Even though the device is used at wider temperatures, the wider temperatures
12、will be limited to those that do not compromise the system performance or application-specific reliability of the device in the application. Specifically, this document is not intended for applications that require the device to function at an operating or environmental stress level that significant
13、ly increases the risk of catastrophic device failure, loss of equipment function, or unstable operation of the device. The use of devices outside the parameters specified by the device manufacturer is discouraged; however, such usage may occur if other options prove to be impossible, unreasonable, o
14、r impractical. Note: Alternate means of thermal uprating may have been performed prior to the implementation of this document by the equipment manufacturer. Rationale for decisions made may have been valid considering the application, semiconductor market conditions, experience with the particular c
15、omponent manufacturer, etc. at the times these decisions were made. Field performance using these methods also may validate their use, however, their continued use must take into account the risk of changes to the subject devices such as feature size reductions, material changes, etc. Copyright Gove
16、rnment Electronics or that a certain course of action is preferred but not necessarily required; or that (in the negative form) a certain course of action is deprecated but not prohibited. 3.21 stress balancing: is a process for thermal uprating in which at least one of the device?s electrical param
17、eters is kept below its maximum allowable limit to reduce heat generation, thereby allowing operation at a higher ambient temperature than that specified by the device manufacturer. 3.22 target temperature range: is the operating temperature range of the device in its required application. Copyright
18、 Government Electronics and To ensure that, if it is necessary to use devices outside the manufacturers specified temperature ranges, it is done with documented and controlled processes that assure the integrity of the equipment. 5. Using Devices Outside the Manufacturers Specified Temperature Range
19、s Devices used outside the manufacturers specified temperature range shall be selected (5. i), their capability is assessed (5.2), their quality is assured (5.3), and documented (5.4), as illustrated by the flow chart of Figure 1. Note: The headings of this clause are keyed to the actions and decisi
20、ons of Figure 1. 5.1 The equipment manufacturer shall design so that, initially and throughout life, no absolute-maximum value for the intended service is exceeded for any device under the worst probable operating conditions with respect to supply voltage variation, equipment device variation, equip
21、ment control adjustment, load variations, signal variation, environmental conditions, variation in characteristics of the device under consideration and of all other electronic devices in the equipment. Device Selection, Usage and Alternatives 5.1.1 Device Technology The technology of a device and i
22、ts package shall be identified and understood in sufficient detail to assess the likelihood and consequences of potential failure mechanisms. It is recommended that the device manufacturer be consulted when a device is proposed for use outside manufacturers specified temperature range. 5.1.2 All dev
23、ices considered for use in wider temperature ranges shall be compliant with the equipment manufacturers ECMP. Compliance with the Electronic Component Management Plan Note: EIA Standard EIA-4899 is recommended as a resource for an ECMP The use of devices outside the temperature ranges specified by t
24、he device manufacturer is discouraged; however, such usage may occur if other options prove to be impossible, unreasonable, or impractical. Justification for such usage may be based on availability, functionality, or other relevant criteria. In no case will such usage result in a design that: Requir
25、es the device to operate at an operating or environmental stress level that significantly increases the risk of catastrophic device failure, loss of equipment function, or unstable operation of the device; or Requires the device to operate beyond the devices maximum junction temperature or any other
26、 limiting temperature, as specified by the device manufacturer, or calculated directly from parameters specified by the device manufacturer. Copyright Government Electronics Using a device specified over the required temperature range, with the identical function, but a wider specified temperature r
27、ange; Using a device specified over the required temperature range, with the identical function, but a different package; Using a device specified over the required temperature range, that has slightly different specified parameter limits, but which still meets the equipment design goals; Using a de
28、vice with the identical function, but a specified temperature range that still meets the application requirement; Using a device specified over the required temperature range, but a different function, and compensating by making changes elsewhere in the equipment design; Modifying the devices local
29、operating environment, e.g., adding cooling, etc.; Modifying the equipment specified ambient temperature requirement, in co-operation with the customer; Modifying the equipment operating or maintenance procedures, in co-operation with the customer; and Negotiating with the device manufacturer to pro
30、vide assurance over the wider temperature range. For most applications, the preferred device for use in a wider temperature range should be the one for which the extension beyond the specified range is least. Note: As an example of this requirement, consider the case in which the required ambient te
31、mperature is 92“C, and no device specified to operate above 85C is available. If the two available devices have specified maximum temperatures of 70C and 85“C, then the 85C device should, in the absence of other factors, be given preference regarding temperature. 5.2 Device Capability Assessment 5.2
32、.1 Device qualification test data and other applicable data shall be analyzed to assure that they support the operation of the device over the end use temperature range and that the package and internal construction type used in device qualification is the same as that to be used in the end applicat
33、ion. Device qualification test data and other applicable data shall be analyzed to assure that the package and internal construction can withstand the stresses resulting from wider temperature cycling ranges, and that the package materials do not undergo deleterious phase changes or changes in mater
34、ial properties in the wider temperatures. Device Package and Internal Construction Capability Assessment 5.2.2 Risk Assessment (Assembly Level) A preliminary risk assessment is prudent at this point to help guide decisions regarding the method(s) of capability assessment to be used, as well as how a
35、nd when they should be applied. Understanding the risks on an application-specific basis enables “risk informed“ decision-making and thereby a prediction of the impact of critical decisions. Copyright Government Electronics and compensating by reducing at least one of the other operating parameters,
36、 e.g., power, speed, to the extent that the junction temperature remains below its maximum rating, with acceptable specified margin. If device stress balancing is chosen for capability assessment, then the process described in Annex B shall be followed. Copyright Government Electronics qualify elect
37、rical performance of the devices over the intended range of operating and environmental conditions after a reliability stress conditioning exposure that reflects the life cycle of the application; and determine a margin, supported by Copyright Government Electronics Required operating temperature ra
38、nge; Manufacturer-specified operating temperature of the device; Alternatives considered and rejected; Process for assuring device capability in the wider temperature range (including test and analysis results); Process for assuring device quality in the wider temperature range (including test and a
39、nalysis results); Required signatures; Risk assessment results. Note 1 : Required signatures include those of the responsible authorities within the equipment designers organisation and, if required, those of the customers. Note 2: The form of Figure 2 is recommended for use in documenting semicondu
40、ctor device usage in wider temperature ranges. 5.5 Device Identification All device identification processes shall be consistent with other industry processes. For each instance in which a device has been determined as having met the applications wider temperature range requirements, through paramet
41、er re-characterization or (5.2.2.2) or device testing (5.2.2.4), the devices status shall be identified as having met the requirements specified in the design activitys uprating specification. The identification requirements shall be as specified in the design activitys uprating specification and in
42、clude the design activitys unique identifier such as the CAGE code, logo, or acronym and the part number assigned by the design activity. For each occurrence of uprating the parts shall be separately identified as meeting the requirements of the application. The method of identification shall enable
43、 all relevant activities such as spares and maintenance to establish that the device has met the requirements of parameter re-characterization or (5.2.2.2) or device testing (5.2.2.4). Copyright Government Electronics zsernative I +-YES+ hange Is datasheet require Re-write d I NO L 4 Circuit Design
44、1 Figure 4 - Flow diagram of parameter re-characterization capability assurance process Copyright Government Electronics N.l is the value of the Student-t distribution at the confidence level (l-a)xlOO% and N-l degrees of freedom. A.3.2.3 Testing Parameter re-characterization tests should be conduct
45、ed over the entire target temperature range, and also at points 15-25OC above the maximum and below the minimum target temperatures. Tests should be conducted at various temperatures within the target temperature range. The number of test temperatures, and the intervals between them, may not be the
46、same for all instances of parameter re-characterization. Factors to be considered in determining the test temperatures may include: Device manufacturers specified temperature range; Copyright Government Electronics Additional test temperatures may be specified on the basis of tests conducted during
47、parameter re- characterization. For example, if a plot of a given parameter vs. temperature indicates the relationship may not be linear, additional tests should be performed to determine its exact nature. A device may satisfy its parameter specifications, but still fail to function. In such a case,
48、 functional testing should be done, and the fault coverage of the test vectors must be considered. Gate level design information is required to develop software to achieve specific fault coverage. If the full set of test vectors is not available, the percent fault coverage is difficult to determine
49、without detailed knowledge of device architecture. In this case, functional tests should include test vectors that exercise the device in a manner similar to that of the application. Testing may be performed in-house or at an external test house. In either case the equipment supplier is responsible for the tests and their results. Prior to parameter re-characterization testing, a set of requirements and limitations on the electrical parameters should be developed. The requirements and limitations depend on the application. Acceptable upper ( MUL - req ) and lower ( MLL
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