I would like to implement a model for the capacitance Cgs that is valid in all regions of operation of a MOS transistor in Verilog-A/MS.

The capacitance model that I want to implement is simplified and is used for hand calculations, normally

Now I want to compare how well it fits with the more precise capacitance expressions of the BSIM model.

So I would like to perform a parametric DC simulation in spectre and to plot the cgs value of the bsim model
by using the OP function of the calculator and compare it with a plot of the capacitance value of my Verilog-A/MS model.

The problem is that in Verilog-A/MS the capacitance value is not calculated directly, but instead the charge is calculated
and than differentiated to get the current contribution of the cap.

q= bla* bla*exp( bla);
i<+ddt(q);

So how can I compare the cap value of the BSIM model with the cap value of my Verilog - A/MS model?

Thanks a lot for the hint!

The cap is my first Verilog -A/MS model and I am quite impressed of the capabilities of modeling that are possible by using this language!

I have read in the book of Ken and Olaf that it is possible to model noise with Verilog-A/MS but the Cadence AMS simulator offers only a DC, AC and transient but no noise analysis.

Do you know how to perform a noise analysis with the Cadence simulator?

Is spectre able to simulate Verilog -A/MS modules? I did not know that. I tried it once but the nelister told me that it does recognize
the view type verilogams. So I switched to the AMS simulator!

So when I have used only Verilog A features in my model file, I could just change the name of my view
from verilogams to veriloga, change the config file to use the veriloga view and than simulate it with spectre!

I checked this and it worked fine, thanks Geoffrey & Bernd  :)