A DfR customer received diodes through broker distribution channels that had shown a very high failure rate during in-process testing. Testing of “as received” diodes showed a significant portion of the diodes did not meet their data sheet reverse breakdown voltage and reverse current specifications. Failure analysis on sample diodes that did not meet their electrical characteristics indicated high current stress damage.
In-house diodes were screened electrically for reverse breakdown voltage/leakage current. A sample of 24 diodes that passed this screening was subjected to a Steady State Operation Life test in accordance with MIL-PRF-19500/477G, Para. 126.96.36.199 and Mil Std 750 Method 1026. The sample of 24 diodes was initially checked for electrical performance per group A (reverse breakdown voltage, reverse current, forward voltage drop at 4A pulse and forward voltage drop at 6A pulse). All diodes passed. At 250 hours into the 1000 hour steady state life test the test articles were subject to an interim group A electrical test. At that point diode D21 was reported as failed.