Military and Space

The Defense Supply Center of Columbus, DSCC, maintains a collection of qualified military specifications, the combined of which comprise a Qualified Parts List, or QPL. In order to be qualified to supply parts to a MIL spec, continuous testing of the production process is performed, and the results submitted to DSCC for approval. A third party review of the performances of the product line allows for the identification of variations in the production processes which may affect the performances of the product, guaranteeing consistency regardless of the date of manufacture of a QPL component. One of the higher levels of MIL spec require a constant calculation of failure rates based on the amount of parts which are tested. These specifications, known as Established Reliability or ER level parts, are guaranteed to perform below a specified failure rate. For example, the RNC90 series of resistor made by Vishay is qualified to a better than 0.01% per 1000 hours failure rate.

For applications used in space projects, a more specific and relevant testing pattern which was developed by NASA may be used as a basis. The EEE-INST-002 guidelines, or Instruction for EEE Parts Selection, Screening, Qualification, and Derating, are used as a basis for the development of several specifications which use foil resistors. By subjecting the resistors to the mentioned sequence of tests, the confidence level of a part to perform in a critical space application is improved. NASA developed the EEE-INST-002 guidelines to be flexible enough to accept any technology and part type, for which Vishay has responded with 5 specifications suggested for these types of critical projects.

Some military applications require either less stringent tests, or a part which is not qualified to a QPL specification. The Defense Supply Center of Columbus also maintains several upscreening plans oriented around products with high demand which have not been QPL qualified. These specifications, known as DSCC specs, consist of a 100% screening test, known as Group A testing, and also a destructive series of tests known as Group B testing. DSCC specifications are easily recognized by engineers, distributors, and QA organizations, and come in a wide variety of part types.

For each level of testing required, Vishay has Foil Resistors which are able to be tested to the desired specification. By having Vishay fully test and supply qualification conformance inspection data relevant to each specific lot, the end-user is guaranteed that the resistors supplied with every lot meet the original design parameters for the relevant application.