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Design >> Analog Design >> Amplifier Gain
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Message started by neuro11 on Mar 27^th, 2013, 12:03am

Title: Amplifier Gain
Post by neuro11 on Mar 27^th, 2013, 12:03am

Hi,
i had been following the TSMC OPAMP schematics design tutorial available online. However i have some problems getting the DC response/Gain shown in that tutorial. I am totally confused about the resulting plot. Can someone explain me a little about DC response gain.

Title: Re: Amplifier Gain
Post by raja.cedt on Mar 27^th, 2013, 12:39am

Hello,
what do you mean by DC response, do small signal analysis for dc gain and dynamics(poles and zero). May be you have start with some basics.
Please post schematic.

Very use-full link

http://www.ee.iitm.ac.in/~nagendra/videolectures/doku.php

Thanks,
Raj.

Title: Re: Amplifier Gain
Post by neuro11 on Mar 27^th, 2013, 12:45am

thanks raja for your reply. I will check the link.
I have attached the circuit

Update: for better picture

Title: Re: Amplifier Gain
Post by neuro11 on Mar 27^th, 2013, 12:51am

the responnse

Title: Re: Amplifier Gain
Post by raja.cedt on Mar 27^th, 2013, 1:47am

hello,
looks fine from this graph, just find the derivative of this curve and see the small signal gain. YOu can only get small signal gain and max and min signals at the input, nothing more.

Thanks,
Raj.

Title: Re: Amplifier Gain
Post by neuro11 on Mar 27^th, 2013, 7:03pm

Hi,
the circuit and the response are from the tutorial. I am struggling to get the response. Its not clear to me whether this response is from Vout vs Vgs (which is common mode). In that case why the Vout is 0 when Vgs is 0. I mean its not clear to me how i can plot this from the above circuit.

Thanks

Title: Re: Amplifier Gain
Post by Lex on Mar 28^th, 2013, 1:46am

Sweep voltage source V4