Monitoring and analyzing the dynamic junction temperature distribution of RF power transistors by using RM-50 infrared micro imager

The authors describe experiments carried out on three types of RF power transistors typically used in the power amplifiers of communication systems. Because of differences found when measuring junction temperatures, a dynamic heat resistance concept was formulated to describe the dynamic thermal characteristics of RF power transistors. Using this concept, the handling capability, burn-in testing, life testing, and the reliability design of RF power transistors were studied. Among the results presented, it was found that the dynamic peak heat resistance is generally lower than the steady peak heat resistance, and steady peak heat resistance is more sensitive than the dynamic peak heat resistance to increasing DC voltage