difference between AC Response Simplis and Spectre

youshang

Q:
The spectre is built from the model of ideal, they expect the result is the same with simplis, but they found the result has difference of AC gain.
They’d like to know which setting will effect the accuracy.

The attached file of sxsch is simulated under the environment of simplis AC.
The attached file of xmcd is AC Response through Mathcad.  


A:
There is not enough information to say anything  definitive about why this difference exists.

However, this is what I suspect.  I am guessing that the Spectre (or MathCad?) results are derived from an average model analysis.  SIMPLIS is not derived from an average model and it does not ignore many large signal nonlinear effects.  So, I would say that it would be safe to bet that the SIMPLIS results are more accurate than the average model results.