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    Folded cascode amplifier is an op-amp or ota?

    Hi

    I want to know is folded cascode amplifier an ota or opamp. Sometimes it is mentioned as ota oand sometimrs as op amp.
    Ota is an op amp without buffer. But when we fabricate an ota chip we use a buffer in front of ota. It means this ota is always an opamp? Am I right please correct me if I am wrong

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    Re: Folded cascode amplifier is an op-amp or ota?

    OTA vs Op Amp is all about the back end (output stage). Either
    one could (but does not have to) use a folded cascode gain stage
    for differential-to-single-ended gain section.

    "Is a transmission a car or a truck?"



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    Re: Folded cascode amplifier is an op-amp or ota?

    Quote Originally Posted by dick_freebird View Post
    OTA vs Op Amp is all about the back end (output stage). Either
    one could (but does not have to) use a folded cascode gain stage
    for differential-to-single-ended gain section.

    "Is a transmission a car or a truck?"
    Cant'understand what you are trying to say. Can you please explain



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    Re: Folded cascode amplifier is an op-amp or ota?

    Hi,

    It just says:
    * The difference between OTA and OPAMP is not the "folded cascode".
    * The difference is the "output stage".

    Klaus
    Please don´t contact me via PM, because there is no time to respond to them. No friend requests. Thank you.



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    Re: Folded cascode amplifier is an op-amp or ota?

    Yes I know but while designing folded cascode ota we dont have a buffer stage. But when we fabricate chip it requires a buffer. Will this OTA become an opamp.
    Whats the difference in the output stage. Is it the load difference?



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    Re: Folded cascode amplifier is an op-amp or ota?

    Attached is the folded cascode. Is it an op-amp or ota?Click image for larger version. 

Name:	foldedcascode.png 
Views:	2 
Size:	7.3 KB 
ID:	150396



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    Re: Folded cascode amplifier is an op-amp or ota?

    But when we fabricate chip it requires a buffer.
    No, why? Particularly not a buffer in front of the OTA block.

    Attached is the folded cascode. Is it an op-amp or ota?
    I believe, you have answered the question yourself. The input stage current is transferred to the output without a buffer. Definitely an OTA.



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    Re: Folded cascode amplifier is an op-amp or ota?

    OTA vs Opamp depends on the output impedance.

    OTA if it has high output impedance.

    Opamp if it has low output impedance.

    See attached.



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