Utilization of Data and Models for COTS Part Reliability Assessment

The use of commercial off the shelf(COTS) parts in space or military applications has been restricted by the perception that the COTS parts do not match the reliability of higher-grade parts. There is also an assumption that the information needed to assess reliability is not available for COTS parts. To evaluate the truth to these perceptions, the information required for a reliability assessment of electronic parts, COTS or not, was catalogued based on failure mechanisms. This article provides a detailed analysis of what types of part level information is available for COTS parts from manufacturers and other external sources. Since temperature is one of the most common stress parameters in common failure mechanisms, a quantitative metric has been developed based on the thermal information availability for a part factoring in temperature ratings, qualifying rating location on the part, thermal resistance, power dissipation, and other factors. A methodology has been developed to account for uncertainty due to incomplete thermal information in reliability estimations. A case study analysis of 22 COTS parts was completed to evaluate the metric and report on trends in thermal information for several types of parts and manufacturers.