A highly physical model of the intrinsic base resistance for a bipolar junction transistor, which includes emitter crowding, base pushout, and conductivity modulation, and which is compatible with the charge-based large-signal bipolar transistor model, is presented. This model, which is an extension of the Hauser model, is derived from a power dissipation calculation and verified with PISCES simulations of the low- to high-current region. It is then implemented in SLICE for CAD. © 1990 IEEE