how to extract Cgs, Cgd by using ADE??

[surno]

Hi all.

i want to extract Cgs, Cgd in CS amp by ADE simulation.
The test bench and results table was attached.
To verify simulation results i was simulation another method.
By using AC simulation, i can extract capacitance of Gate.
The result of AC simulation total gate cap is 93.76fF and using OP simulation is 26.54fF.
Why these two results different each other?
I don't know what is wrong.
Which one is right?
Please give me a favor and a simulation method.

Thanks.

 

[chris.mourad]

Hi

In your own computation, did you divide by 2*PI? This is a mistake regularly done.

What is the Vin you apply at the gate of the NMOS? and the drain current?