Stubborn model of a nonlinear capacitor

I found a factory model of a capacitor, and I wanted to get a similar non-linear capacitor model. I made many different attempts, but nothing succeeded.
Please give me an example of a non-linear capacitor. That example from HELP did not give me any information.


Alexander Bordodynov.

Rhino,
You didn’t understand what I wrote. That is exactly the example I was writing about. It does not contain the necessary information!
I need to use different attributes.

Alexander.

I was misunderstood here. I need a capacitor with the following parameters: CSAT, VSAT, SATFRAC.
Various combinations of these parameters and their values did not give me a properly functioning capacitor. All the time it turned out to be nonsense! Give me an example of a capacitor with these parameters, please.

Alexander.

I figured out the model myself. It is only suitable for TRAN analysis .In LTspice it is not. In it, the model works in AC analysis as well. I made the determination of the nonlinear capacitance in TRAN analysis by simultaneously feeding a large variable offset together with a 1 mV signal and a frequency of 1 MHz.
Then I used MEAS.
I also found a BUG in the QSPICE message!
Fatal error: C1: SATFRAC × CAPACITANCE must be larger than VSAT.
VSAT ---- CSAT!!!

I figured out the model myself. It is only suitable for TRAN analysis .In LTspice it is not. In it, the model works in AC analysis as well. I made the determination of the nonlinear capacitance in TRAN analysis by simultaneously feeding a large variable offset together with a 1 mV signal and a frequency of 1 MHz.
Then I used MEAS.
I also found a BUG in the QSPICE message!
Fatal error: C1: SATFRAC × CAPACITANCE must be larger than VSAT.
Correct VSAT to CSAT !!!

Alexander

Right, OK it now uses the biased DC value in the .AC:

Thank you very much.