Transcapacitances and Bias Dependent Time Delay and Base Resistance Expressions for Accurate Large Signal Modeling of HBTs

摘要

Transcapacitances and bias dependent total time delay and base resistance expressions for accurate modeling of heterojunction bipolar transistors (HBTs) are proposed. Small-signal equivalent circuit parameters are first extracted over the entire forward bias region using multi-bias S-parameter measurements. Relations taking into account the variation of the bias dependence of circuit elements on collector-emitter voltage and collector current are then developed. The resulting expressions are used to construct a large signal model, which is then tested and compared to a dedicated small-signal model and measurements. The developed expressions may be used to improve the accuracy of other large signal models.