Improved description of base dynamics in the modelling of bipolar transistors

An improved non‐linear high‐frequency model for the bipolar transistor is presented, based on considerations of the dynamics of the charge stored in the base region. the model incorporates higher‐order circuit elements in order to obtain increased accuracy in circuit simulation at high frequencies. the model is derived from device physics by solving the diffusion equation in the base region by means of a quasi‐static expansion. the result is a more accurate circuit representation, which can be added to existing bipolar transistor models. Simulation examples are given and the possible convergence problems associated with the model are discussed