Implementation of nonquasi-static effects in compact bipolar transistor models

Large-signal implementation of nonquasi-static (NQS) effects in bipolar transistors is reviewed. An approach is proposed to introduce first-order NQS correction to typical quasi-static phenomenological models. Both charge- and noncharge-conserving implementations are considered. The resulted large-signal equivalent-circuit model compares well with the two-dimensional physical model in simulating HBT transient response under high-current operations. The present approach advances the state-of-the-art by allowing arbitrary bias dependence of transit times in large-signal NQS models.