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  1. #1
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    poles and zeros of Two satge folded cascode

    I'm going to design a two stage folded cascode OTA.
    first stage is folded cascode(nmos input pair) to provide gain
    second stage is common source to increase the output range
    compensation is cascode compensation


    My question is in my circuit, how to find poles and zeroes?
    It had a compex trasformer Eq. & I couldnt simple it.



    Thanks a lot!

    •   Alt29th March 2013, 00:47

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  2. #2
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    Re: poles and zeros of Two satge folded cascode

    I am assuming that you are trying to simulate and get the poles. for hand calculations you can look at any book for opamps and it will have the derivations.

    you basically tie the op-amp in negative feeback mode with an inductor(1GHenry) so that is in stable DC bias state and the input to the resistor. They you put a ac signal to the positive terminal and frequency sweep and you get the two poles ...


    Quote Originally Posted by vaah View Post
    I'm going to design a two stage folded cascode OTA.
    first stage is folded cascode(nmos input pair) to provide gain
    second stage is common source to increase the output range
    compensation is cascode compensation


    My question is in my circuit, how to find poles and zeroes?
    It had a compex trasformer Eq. & I couldnt simple it.



    Thanks a lot!



    •   Alt29th March 2013, 01:00

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  3. #3
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    Re: poles and zeros of Two satge folded cascode

    Tnx a lot
    But I wanna determine poles/zeros by hand(2 stage folded cascode-sigle ended)
    I wasnt able to find it in any book.
    Can u tell me what book(s)?

    Tnx in advance



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