Seahs,

  Assuming that you have an OTA for use in switched capacitor type
application and you want to check the behavior stand alone. Also
assuming that you are using Spectre. Try the the following:

1) Use capacitive feedback to close the loop. Cinput=Cfeedback
2) Use the the analysis dependent switches to set the transient
   analysis initial conditions, that is, short the input to the output.
   You should also short the input and output for  dc analysis and
   transient initial conditions. The switch should be open for transient
   analysis.
   --> Setting the transient initial conditions emulates the operation
         of the switched capacitor circuit when the feedback switch
         is closed and sets the operating point for the OTA.
3) Once the initial conditions are set then apply the sine wave during
   transient analysis.

This approach generally works at 0.18um and above, not sure
whether this will work with 65nm, ... due to drift of the operating
point due to gate leakage.

                                                                 Best Regards,

                                                                     Sheldon