You need to run a PSS analysis before running PAC. PSS analysis requires that the have a periodic steady-state solution. It sounds like your integrator is actually integrating, so that output is not periodic. To run PSS/PAC you probably want to remove the large signal input, provide feedback so that there is a stable periodic operating point, and then run PSS/PAC.
Quote:I also was told by the local cadence rep spectre wouldn't work with chopping.
That person is wrong.
Quote:1)When performing the PAC of a SC integrator. does the output voltage of the PAC represent the linearized closed loop gain or the openloop gain?
PAC just computes voltages and currents. The testbench determines what is measured.
Quote:2)In documentation it mentions that for pss that only the sample clock is being driven, such as in mixer or sc circuit, but what about when you have two clocks of different frequency, in my case the sample clock and the slower chopping clock(chopping is half freq of sampling clock). Pss forces me to state fundamental freq as the slowest freq to obtain periodicity, but I also saw references of the fundamental clock being the sample rate.
There must be a periodic solution, so the chopping and sampling frequencies must be co-periodic. Use the lowest common multiple as the fundamental frequency.
Quote:3) Question about the linearizing of the transfer function , if this is a sc integrator whose output is increasing by 100mV steps due to a given input every 1us, does the linearization mean it converts the transfer function that results in a discrete time stair step to a continuous time straight line of form out=Acl*in?
Linearization means that it is as if the input signal is very small, so small that it cannot generate a nonlinear response.
-Ken