A theoretical model for predicting LED product lifetime based on solder joint failure

LED A-lamps are used in many types of lighting fixtures; however, these lamps can experience different thermal environments and use patterns (on-off switching), resulting in system life that varies in different applications. A recent study showed that on-off switching negatively affects LED system lifetime, and solder joint failure was the main reason. The goal of this study was to investigate and identify a theoretical model that can be used to predict LED A-lamp failure, when the failure is mainly due to solder joint failure. Although several models for solder joint fatigue failure exist in the electronics industry, the Engelmaier model is the most commonly used in industry standards. The study presented here showed that the Engelmaier model with modified fatigue ductility exponents provided a better fit to the experimental lifetime data for LED A-lamps. This paper describes the Engelmaier model prediction method for LED A-lamp failure.