Collector-Emitter Current

The forward and reverse components of the collector-emitter current are modeled in a manner very similar to the Gummel-Poon model, but with somewhat more flexibility. Observation of collector-emitter current behavior has shown that the forward and reverse components do not necessarily share identical saturation currents, as in the Gummel-Poon model. The basic expressions in Agilent EEBJT2, not including high-level injection effects and Early effects, are:

where ISF and ISR are not exactly equal but are usually very close. NF and NR are not necessarily equal or 1.0, but are usually very close. Careful control of ambient temperature during device measurement is required for precise extraction of all of the saturation currents and emission coefficients in the model.

The effects of high-level injection and bias-dependent base charge storage are modeled via a normalized base charge, in a manner similar to the Gummel-Poon model:

where

and