How to simulate switch capacitor circuit in ADS

I wonder how to simulate switch capacitor circuit such as SC filter 's frequency response in ADS , in cadence I can use PSS and PXF , but how can I do it in ADS?Does anyone know it ? Thanks very much!

i think u don't have other option rather than the transient smulation.

u can't use the HB engine in ADS

Khouly

But how can I get the frequency response in tran? Could u please explain that in details, thanks

I don′t know ADS. However, you can do an exact ac analysis (frequency response) with the help of each general purpose simulation program if you replace each s/c unit with a time continuous equivalent (consisting of a positive or negative resistance and a delay unit). If you are interested I can give you some more information and references.

Thanks,LvW
use CT subsitute is a good idea, but unfortunately, we can not get some second order effect such as charge inject or parasite in our simulation , it's not very convenient for performance improve,isn't it?

Yes, I agree with that. Substitution of s/c elements by continuous time units can be recommended when you are interested in the principle and ideal frequency response
(e.g. for tutorial purposes). Parasitic effects are hard to cover.

for switched capacitor circuit use the transent analysis , then FFT to get the frequency response of the circuit

khouly

Thanks khouly
I have tried this before,but still have some problem , when you do FFT with trans sim, you get the output spectrum with center freq and harmonics, so you can only get voltage or power of one point frequency , I wonder if there is some way to get the steady state and do AC sim ?

in ADS i don't think AC simulation can handle this. if u are interested in the steady state , u need to run the transient for long time.

another way. u can use the HB with large order about 9 to 13 ,
i didn't try it before. but u need to ask agilent guys

khouly