AC analysis

Hi!

I want to do an ac analysis to a single-ended opamp.
I'm having some difficulty to decide how to do the test bench's and if
I should add a vsin signal to the circuit. How should I specify the
input signal?

Furthermore, Can anyone tell me what's "Y element"?

Thanks

 

I want to do an ac analysis to a single-ended opamp.

It doesn't matter which type of source you are using, as they all have AC parameters available.
Rather choose it according to the signal shape you want during transient simulation.

For AC, the simplest setting is to just set the AC magnitude to 1.

See 'spectre -h vsource' for a list of parameters (I'm assuming you're using spectre).

I guess it depends... could be an element with the shape of a Y. Or an element modeled with
Y-parameters (http://en.wikipedia.org/wiki/Admittance_parameters).



Stéphane

 

At first, thanks for your reply.
"Rather choose it according to the signal shape you want during
transient simulation. "
Sorry, I didn't understand. Did you mean that if I want to put, in the
transient simulation a DC signal, I should at it in the AC simulation?
I don't know if it helps, but the opamp will have feedback (it will
make part of a current source composed by an opamp, a nmos and a
resistor).

Thanks

 

It means that you keep your analogLib/vdc device, just fill the 'Ac
Magnitude' field. Puting '1' is very handy because it makes your Gain
directly readable without any multiplication/division.

Riad.