BJT model

The Multisim BJT model is based on the Gummel-Poon SPICE3 BJT model. It contains a number of enhancements, including improved convergence and support for PSpice parameters.

See below for details. 

In the following sections, all transistor node voltage references are with respect to the internal nodes (that is, the ohmic resistance pin that is connect the inside of the structure.) 

Static model 

Actual base parasitic resistance 

Capacitances 

Base-emitter capacitance: 

Base-collector capacitance: 

Extrinsic-base to intrinsic-collector capacitance: 

Substrate junction capacitance:

Quasi-saturation effect: 

Temperature effect: 

Parasitic resistances thermal noise: 

Base and collector currents shot and flicker noise: