Multi-finger power HBT model for nonlinear circuit simulation

A multi-finger power HBT model is developed by incorporating multiple unit finger HBT models with a multi-port thermal network. Each unit finger HBT model exhibits temperature and bias variations. The multi-port thermal network represents self-heating and thermal coupling effects. This power HBT model, implemented in a nonlinear circuit simulator, can be used to perform DC, small signal, and large signal simulation. Unique behaviors of multi-finger HBT, such as current collapse and the decrease in power output, are reproduced. The influence of ballasting resistance is also investigated.