Failure Analysis and Reliability Assessment of Electronic Connectors

There are many standards set up and methods proposed for the reliability prediction of electronic products. Among them, Telcordia SR-332 Reliability Prediction Model is frequently used in telecommunication industry. The approach provides us an easy way to estimate a product’s reliability through examining failure-rate tables and environmental factors for a variety of electronic devices. Those tables are constructed based on data collected by and experiences gained from several suppliers. The approach is too rough for devices such as electronic connectors which are extremely multitudinous and, therefore, results in inaccurate reliability prediction. The major purpose of the present study is to design a test program and analyze its result to find the reliability of a particular type of connector. First of all, Failure Mode and Effect Analysis (FMEA) and Fault Tree Analysis (FTA) are used to identify the most relevant failure modes of the electronic connector. Based on results of FMEA and FTA, a series of Accelerated Test (AT) is performed to find the failure trend of the connector. After obtaining failure data of tested connectors by regression analysis, the study uses goodness-of-fit test and Series System Reliability Model to quantify failure data. The result shows that the connector’s Mean Time To Failure (MTTF) is 990.86 hours under the reference condition of 40 ℃/30% RH if Eyring model is adopted. It is quite different from the value of 181,908.81 hours calculated from the failure rate of 5,497.26 FITs (Failures Per 109 Device Hours) which is, in turn, obtained based on Telcordia SR-332 Reliability Prediction Model. After the tests, the PCB gauging holes of the connectors are found to be corroded. It may result in measuring error. Therefore, it is suggested that gauging holes should be strengthened to resist corrosion for accelerated tests to be performed in the future. For the studied connectors, this measuring error causes the reliability predicted above falls on the conservative side, i.e., the real MTTF should be longer than 990.86 hours. Aside from the above results, a relation between the contact normal force and temperature is found for the studied connectors. It can be used to improve the design of the studied or similar types of connectors.