CJS in Bipolar Device Model

[batelab]

What is "Cjs" in a PNP device model? What's this capacitance physically?

Is there any trick one could use to get the PNP device with large Cjs to run faster?

 

[erikl]

What is "Cjs" in a PNP device model? What's this capacitance physically?

It's the zero bias collector-substrate depletion capacitance, s. PDF below.

Is there any trick one could use to get the PNP device with large Cjs to run faster?

Cjs decreases when the collector-to-substrate voltage increases. And you can reduce its effect if you use a cascode stage.