Remaining life assessment of aging electronics in avionic applications

This paper describes an assessment of the remaining life of solder interconnects for 13 different insertion mount packages used in an engine control electronics. The assessment consisted of using simulation to determine the mean time to failure of solder joint interconnects between the package leads and printed wiring boards under applied temperature cycle conditions. The simulation results were confirmed by accelerated testing for a 132-pin grid array (PGA) and field data for a 40-lead side-brazed dual in line package (DIP). Loading conditions include an accelerated test condition of -45° to 100°C and a service loading condition of 10° to 75°C with an extended dwell at 60°C. Predicted mean interconnect life expectancy ranged from 4,000 in the worst case to 130,000 cycles. Results indicate a brazed leaded ceramic dual inline package with 40 leads is likely to fail first and a 2 lead plastic encapsulated axial capacitor is the least likely to fail. The early failure of the 40-lead side-brazed DIP was confirmed by the service performance data. The service life remaining after failure of the 40-lead side-brazed DIP was estimated to be 7,800 cycles.