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https://designers-guide.org/forum/YaBB.pl Design >> Analog Design >> Pole zero plot https://designers-guide.org/forum/YaBB.pl?num=1159169118 Message started by hande.vinayak on Sep 25th, 2006, 12:25am |
Title: Pole zero plot Post by hande.vinayak on Sep 25th, 2006, 12:25am Hello to all, I am designing a Folded OTA,please can anybody tell me how to plot a pole zero plot for finding a stability? I am working on Cadence Analog Design Environment tool. Thanks. :-[ |
Title: Re: Pole zero plot Post by packiaraj on Sep 25th, 2006, 3:55am Why do you want to see the PZ plot to determine the stability? I feel Spectre's STB analysis is far better than PZ analysis to simulate stability margins. PZ analysis will give only the location of Poles and Zeros (a lot of them actually!!!) and NOT the parameters Like Phase Margin and Gain Margin. PM and GM are the impotant stability parameters as they would tell you how far is your circuit from becoming unstable. Thanks, Packiaraj.V. |
Title: Re: Pole zero plot Post by hande.vinayak on Sep 25th, 2006, 10:47pm Thanks, But as I am new this field,I wanted to know that while moving into the 'STB' anlysis.What we have to write into 'Probe Instance'----Block?I wanted to check open loop gain and open loop stability. Thanks. Vinayak. |
Title: Re: Pole zero plot Post by semitao on Sep 27th, 2006, 6:16pm Hi, Does anyone have any tutorial about spectre PZ & STB analysis? best regards. |
Title: Re: Pole zero plot Post by Ken Kundert on Sep 27th, 2006, 7:26pm Background on STB: http://www.thekunderts.net/ken/docs/c%26d2001-01.pdf. -Ken |
Title: Re: Pole zero plot Post by Andrew Beckett on Oct 28th, 2006, 7:22am I sometimes use pz analysis to figure out if the circuit is unstable - because you can tell this without having to analyse specific loops - it will analyse the whole circuit. However, if you want to get information about the amount of margin, then stb is the man for the job. In addition to the reference that Ken posted, I believe there is an application note on http://sourcelink.cadence.com . If you can't find it, file a service request, and your friendly Cadence application engineer can locate it for you. Regards, Andrw. |
Title: Re: Pole zero plot Post by hchanda on Nov 2nd, 2006, 6:01pm Hi ken, I am looking for the document that talks about the spectre stability analysis. I was seaching for it in the forum and found the pointer to document mentioned by you (please see below) Background on STB: http://www.thekunderts.net/ken/docs/c%26d2001-01.pdf . But I am not able find any document at that pointer. Could you please provide the pointer to document? Thanks, Hc |
Title: Re: Pole zero plot Post by Ken Kundert on Nov 2nd, 2006, 7:52pm The paper has been moved to http://www.kenkundert.com/docs/cd2001-01.pdf. |
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