How to simulate the noise of fully differential AMP?

[winsonpku]

Dear all:
I want to simulate the noise of fully differential AMP use hspice.someone told me that the old version can't support this function,because the noise inculdes common mode and differential mode. I didn't find much useful informatin in hspice manual,who can tell me?
Thanks all for your help!

Best Regards

winson

 

[abcyin]

I think it can be done by the following method:
.noise ........
Simulate.
In the .lis file, search for the total equivalent output noise voltage at the freq you are interested in. And then find the equivalent input source noise, the former devided by the later, then 20log, you get the Noise Figure.

Added after 2 minutes:

PS:
For the differential AMP,I think you should use the bidirectional Balun.

 

[winsonpku]

Thanks first,what's the meaning of "bidirectional Balun"

I think it can be done by the following method:
.noise ........
Simulate.
In the .lis file, search for the total equivalent output noise voltage at the freq you are interested in. And then find the equivalent input source noise, the former devided by the later, then 20log, you get the Noise Figure.

Added after 2 minutes:

PS:
For the differential AMP,I think you should use the bidirectional Balun.