questions about BSIM4 gate resistance model

[sapphire]

rgatemodel bsim4

Hi there,

It provides four options to model gate resistance. The 3rd and 4th options consider channel NQS effect, but I am not sure about what's exactly the difference? Therefore, I don't know how to choose between these two.

Actually, I am doing a simple noise analysis on a common-source amplifier. These two options give much difference noise voltage from gate resistance as a whole.

Thanks

Sapphire

 

[erikl]

bsim gate resistance calculation

Up to the BSIM4.6.2 Manual (p. 79 ff., resp. 87 ff.), the rgateMod = 3 (IIR model with two nodes) supports the most exact description of gate resistance.
Select the default modes (= 0) for rnqsMod and acnqsMod for this case.

The IIR model (which is used in this case) should not be used together with the charge-deficit NQS model at the same time.