SCALABLE SMALL-SIGNAL MODEL FOR BJT SELF-HEATING

Abstract

The effects of self-heating on BJT behavior are demonstrated through measurement and simulation. Most affected are the small-signal parameters Y22 and Y12. A frequency-domain solution to the heat-flow equation is presented that applies to any rectangular emitter geometry. This model, although simple enough for CAD, predicts thermal spreading impedance with good accuracy for a wide range of frequencies.