Hi All,

I tried to use PSS+PAC simulate a very simple SC circuit (please refer to the attached Picture1). First, the two equal caps are charged to 1.8V and 0.8V, then open the charge switches and then close the middle switch so that the two caps share the chargers and reach the same voltage. Principly, the voltage of sigB increase by 0.5V and the voltage of rstB decreases by 0.5V.  The PSS steady state solution is correct (please refer to the attached Picture2).
However, the PAC results are not correct (please refer to second picture). The clock is about 4.6Mhz. From PAC, the changes of sigB and rstB are halved (only 0.25V).  Picture 3 shows PAC results. Anyone can try this circuit.
I was confused by the PAC results. Can anyone give me some hint what was going on?

Thanks,
Lunren

Picture3 (PAC results)