1、EIA STANDARD Use of Semiconductor Devices Outside Manufacturers Specified Temperature Ranges EIA-4900 NOVEMBER 2001 ELECTRONIC INDUSTRIES ALLIANCE GOVERNMENT ELECTRONICS AND INFORMATION TECHNOLOGY ASSOCIATION A SECTOR OF COPYRIGHT Electronic Industries AllianceLicensed by Information Handling Servic
2、esCopyright Government Electronics and upon 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
3、 exited the military market in recent years, 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 Commercial: 0C to +70“C
4、 If there are no reasonable 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 equipmen
5、t manufacturers to meet the 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 us
6、age. The intent of this document 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 intend
7、ed to operate under conditions 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 temperature
8、s, the wider temperatures 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 str
9、ess level that significantly 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 i
10、mpossible, unreasonable, or 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, experi
11、ence with the particular component 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 ch
12、anges, etc. COPYRIGHT Electronic Industries AllianceLicensed by Information Handling ServicesCopyright Government 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
13、 stress balancing: is a process for thermal uprating in which at least one of the devices electrical parameters 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
14、temperature range: is the operating temperature range of the device in its required application. COPYRIGHT Electronic Industries AllianceLicensed by Information Handling ServicesCopyright Government Electronics and To ensure that, if it is necessary to use devices outside the manufacturers specified
15、 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 Ranges Devices used outside the manufacturers specified temperature range shall be selected (5. i), their capability i
16、s 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 decisions of Figure 1. 5.1 The equipment manufacturer shall design so that, initially and throughout life, no absolute-
17、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, equipment control adjustment, load variations, signal variation, environmental conditions, variation in characteristic
18、s 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 its package shall be identified and understood in sufficient detail to assess the likelihood and consequences of p
19、otential 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 devices considered for use in wider temperature ranges shall be compliant with the equipment manufacturers ECMP. Com
20、pliance 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 the device manufacturer is discouraged; however, such usage may occur if other options prove to be impossible, unr
21、easonable, 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: Requires the device to operate at an operating or environmental stress level that significantly increases the risk of c
22、atastrophic 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 limiting temperature, as specified by the device manufacturer, or calculated directly from parameters specified
23、by the device manufacturer. COPYRIGHT Electronic Industries AllianceLicensed by Information Handling ServicesCopyright Government Electronics Using a device specified over the required temperature range, with the identical function, but a wider specified temperature range; Using a device specified o
24、ver 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 device with the identical function
25、, 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; ModiSling the devices local operating environment, e.g., add
26、ing cooling, etc.; ModiSling the equipment specified ambient temperature requirement, in co-operation with the customer; ModiSling the equipment operating or maintenance procedures, in co-operation with the customer; and Negotiating with the device manufacturer to provide assurance over the wider te
27、mperature 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 temperature is 92“C, and no device
28、 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 5.2.1 Device Package and Internal C
29、onstruction Capability Assessment 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
30、 to be used in the end application. 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 ph
31、ase changes or changes in material properties in the wider temperatures. 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 and when they should be applied.
32、Understanding the risks on an application-specific basis enables “risk informed“ decision-making and thereby a prediction of the impact of critical decisions. COPYRIGHT Electronic Industries AllianceLicensed by Information Handling ServicesCopyright Government Electronics and compensating by reducin
33、g at least one of the other operating parameters, 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 followe
34、d. COPYRIGHT Electronic Industries AllianceLicensed by Information Handling ServicesCopyright Government Electronics qual electrical performance of the devices over the intended range of operating and environmental conditions after a reliability stress conditioning exposure that reflects the life cy
35、cle of the application; and determine a margin, supported by COPYRIGHT Electronic Industries AllianceLicensed by Information Handling ServicesCopyright Government Electronics Required operating temperature range; Alternatives considered and rejected; Equipment in which the device is used Manufacture
36、r-specified operating temperature of the device; 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 analysis results); Required signatures; Risk assessment
37、 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 semiconductor device usage in wider temperature ranges. 5.5 Dev
38、ice 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 parameter re-characterization or (5.2.2.2) or device testing
39、(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 include the design activitys unique identifier such as t
40、he 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 all relevant activities such as spares and maintenanc
41、e 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 Electronic Industries AllianceLicensed by Information Handling ServicesCopyright Government Electronics N.l is the value of the Student-t distribution at the c
42、onfidence level (l-a)xlOO% and N-l degrees of freedom. A.3.2.3 Testing Parameter re-characterization tests should be conducted 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 temper
43、atures within the target temperature range. The number of test temperatures, and the intervals between them, may not be the same for all instances of parameter re-characterization. Factors to be considered in determining the test temperatures may include: Device manufacturers specified temperature r
44、ange; COPYRIGHT Electronic Industries AllianceLicensed by Information Handling ServicesCopyright Government Electronics Additional test temperatures may be specified on the basis of tests conducted during parameter re- characterization. For example, if a plot of a given parameter vs. temperature ind
45、icates 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, functional testing should be done, and the fault coverage of the test vectors must be consider
46、ed. 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 without detailed knowledge of device architecture. In this case, functional tests should includ
47、e 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 requi
48、rements and limitations on the electrical parameters should be developed. The requirements and limitations depend on the application. Acceptable upper ( MUL - req ) and lower ( MLL - req ) margin limits should be established for each modified parameter. Other thermal data obtained from the device ma
49、nufacturer, e.g., thermal conductivity, etc.; Other uses of the test data, e.g., performance derating; and Previous relevant experience with the device. A.3.2.4 Assessment of Electrical Test Results If the test results indicate that there are no functional failures, if no discontinuities are observed in any of the parameter vs. temperature plots, and if the modified parameter limits are acceptable for the application, then the uprating process can be considered successful. A.3.2.5 Re-characterized Parameter Value Calculation Re-characterized parameter values include both
