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Design >> Analog Design >> Folded cascode opamp
https://designers-guide.org/forum/YaBB.pl?num=1160108545

Message started by hande.vinayak on Oct 5^th, 2006, 9:22pm

Title: Folded cascode opamp
Post by hande.vinayak on Oct 5^th, 2006, 9:22pm

Hi,
I wanted to design a opamp with UGB 180Mhz with PM around 50 degrees and open loop gain 65dB.As per this spec. can you help me to decide a proper opamp config.If anybody is having a papera regarding folded cascode,can you like share with me?
Thanks.

Title: Re: Folded cascode opamp
Post by bharat on Oct 5^th, 2006, 10:30pm

Folded cascode is preferred because of head room issue. If you are good in head room there is no need of folded cascode. I believe in KISS (keep it simple and small ) philosophy. Bias generation is little tricky in folded cascode.
-Bharat

Title: Re: Folded cascode opamp
Post by hande.vinayak on Oct 6^th, 2006, 3:27am

Thanks Bharat.
Can you suggest any paper in the case of Fully Differential FC OTA?
Thnx.

Title: Re: Folded cascode opamp
Post by Raul on Oct 10^th, 2006, 2:25pm

Are you only driving capacitance? If so, a folded-cascode is the best option.

Title: Re: Folded cascode opamp
Post by packiaraj on Oct 11^th, 2006, 8:40pm

Look for the attached JSSC paper on Fully Differential Folded Cascode OTA Design.
Thanks,
Packiaraj.V.

Title: Re: Folded cascode opamp
Post by jbdavid on Oct 11^th, 2006, 11:07pm

Unless that was YOUR paper, its covered by an IEEE copyright..
ok even if it was its covered, but IEEE allows you to distribute a few copies of your own paper..

In either case,
posting it to a website like this is illegal!
It would be better to post a link

http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=1702&arnumber=45013&count=38&index=31

Title: Re: Folded cascode opamp
Post by hande.vinayak on Oct 12^th, 2006, 12:14am

Thanks Packiaraj.V.,it really helped me a lot.

Title: Re: Folded cascode opamp
Post by packiaraj on Oct 12^th, 2006, 1:56am

I thought before posting....but ?... OK David... Taken...

Thanks,
Packiaraj.V.

Title: Re: Folded cascode opamp
Post by SATurn on Oct 12^th, 2006, 9:17am

Please remind that if load capacitor is large, then it is very difficult to achieve the desired specs. In this case you must use another class of amplifier (e.g., class-AB) ...