Reliability prediction using conventional constant failure models by standard books in early phases of electronics dominates wide acceptance. But after 1980s, there was wide variation in electronic technology which made above models obsolete. Physics of Failure approach provides information on basic failure phenomenon with failure mechanisms and failure modes becomes prominent as it entirely depends on materials, processes, technology etc. Constant fraction discriminators which are failing frequently in the field need to be studied and this paper provides information on failure characteristics using physics of failure approach. Apart from that, we combined statistical methods such as Design of Experiments, Accelerated testing and failure distribution models to quantify time to failure of this electronic component by radiation and temperature as stress parameters.