Closed-loop gain of SC amplifier by AC analysis

1. Closed-loop gain of SC amplifier by AC analysis

Hi,

Is there any way to to calculate closed loop gain of an SC amplifier by using ac analysis? In transient analysis the SC gain in amplifier is desired, but in ac analysis it is not correct. Can anybody please tell me whether there is a way to do this by ac analysis?

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2. Re: Closed-loop gain of SC amplifier by AC analysis

Use slave small signal analysis subjected to master large signal periodical steady state analysis.
Such analyses are available in Synopysis HSPICE, Sylvaco SPICE, Cadence Spectre, etc.

There you can choose shooting newton method as analysis as periodically steady state analysis.

3. Re: Closed-loop gain of SC amplifier by AC analysis

There is a periodic AC analysis also in Cadence Spectre RF. Maybe that is also good. And you can save the operating points of the stable amplifier from simple transient analysis also and you can run AC with those.

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4. Re: Closed-loop gain of SC amplifier by AC analysis

Yes - you can.
The most simple and exact method is to replace the s/C blocks with time-continuous (artificial) elements which then allow usage of the well-known simulation packages.
In this case, also the periodic shape of the transfer function is preserved.
For this purpose, two different methods do exist
* Storistor method
* Coupled controlled current sources

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5. Re: Closed-loop gain of SC amplifier by AC analysis

Originally Posted by LvW
* Storistor method
Hello Lutz, what's that? Couldn't find anything about Storistor neither in Wiki nor in G00GLE.

7. Re: Closed-loop gain of SC amplifier by AC analysis

Originally Posted by frankrose
Thank you, frankrose! Finally I also found it in LvW's book.

8. Re: Closed-loop gain of SC amplifier by AC analysis

Originally Posted by erikl
Hello Lutz, what's that? Couldn't find anything about Storistor neither in Wiki nor in G00GLE.
See here: Nelin (1983): IEEE Trans. Circuits and Systems, CAS-30, 43-48.

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9. Re: Closed-loop gain of SC amplifier by AC analysis

Originally Posted by LvW
See here: Nelin (1983): IEEE Trans. Circuits and Systems, CAS-30, 43-48.
Thank you! Meanwhile I also found it in an old thread where you contributed - and in your book.

10. Re: Closed-loop gain of SC amplifier by AC analysis

Originally Posted by erikl
Thank you! Meanwhile I also found it in an old thread where you contributed - and in your book.
Eine ausführlichere Darstellung des Nelin-Verfahrens ist im Filterbuch:
http://www.springer.com/de/book/9783540717379

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