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Design >> Mixed-Signal Design >> Pstb Analysis for SC CMFB
https://designers-guide.org/forum/YaBB.pl?num=1191533499

Message started by analog2000 on Oct 4^th, 2007, 2:31pm

Title: Pstb Analysis for SC CMFB
Post by analog2000 on Oct 4^th, 2007, 2:31pm

Hi,
Could anyone help me with pstb analysis of sc cmfb for a diff amp. I have been trying to run pstb but pss fails for a differntial sc gain. The gain stage uses a diff amp with sc cmfb ?
thanks a lot
Best Regards
analog2000

Title: Re: Pstb Analysis for SC CMFB
Post by tosei on Oct 6^th, 2007, 9:48am

Hi,

When you say tje pss fails for a differential sc gain, what do you exactly mean: it does not converge or it is giving you unexpected results?

Regards
tosei

Title: Re: Pstb Analysis for SC CMFB
Post by analog2000 on Oct 6^th, 2007, 2:37pm

HI there,
It fails to finish the pstb analysis. The pss analysis is finished, however, there were convergence warnings. ?
I tried relaxing the accuracy requirements, changed the pss algorithm from balanced to shooting, but of no avail. I also tried changing the clock frequency and the input frequency for my sc gain stage. No luck yet
thanks

analog2000

Title: Re: Pstb Analysis for SC CMFB
Post by tosei on Oct 8^th, 2007, 7:37pm

Hi,

I assume you are using the cmdmprobe from the analoglib. If this is the case, make sure the probe is properly connected according to the type of analysis you are trying to run (-1 for diff mode, 1 for cm mode). I saw convergence problems due to this in the past.

tosei

Title: Re: Pstb Analysis for SC CMFB
Post by analog2000 on Oct 10^th, 2007, 3:34pm

Hi,
I am not using cmdmprobe
analog2000