hspice
New Member
Offline
Posts: 4
|
Hi, there:
I'm wondering if possible using transient with ac analysis instead of PSS or seperated test bench for SC curcuit evaluation. There is a feature at IC61x, that we can insert ac analysis to transient analysis after specified time points for ac. Then we can pick, say a sampling & hold circuit as test bench, after picked up the point desired, just to break the feedback, and maintain op for ac analysis. In this way, we can evaluate the opamp within real application environment, better than seperated AC test bench! However, I found there were two issues within this idea, the first, I have add a ac source at the input terminals of opamp, but at SH mode, those terminals are always high impedense point. The second one, I have to make a component which break at AC analysis and short at transient mode. By verilogA model, I did have one with flaw. By using "analysis" command, it can be turned to open mode(large resistor) , but can't be turned back, loooks like spectre did not initialize simulation mode back to transient after AC analysis points.
Does anyone can commend my idea and solve my questions regarding to this method? I do think this way should work, unless something inside spectre bars
THX
vincent
|