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How to determaine the output impedance?

xzsawq21
on Jun 5, 2017

Hello

I have a VCCS based on AD8130.  After many googling and studying.. now I'm frustrated!

for checking the output capacitance usually I put a 1Kohm resistor on the output and check the 3-dB corner frequency. so the output capacitance is C=1/(2*pi*R*f3dB)

But I really I don't know how I should calculate the output impedance of the VCCS.

Regards

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  • 0 on Aug 18, 2017 11:58 AM

    Thank's for your attention and recommendation

    I've studied many papers about VCCS. (almost all papers )

    it is one of the first application notes that I had studied before  

    one of the worst drawback of such circuit is the mismatch between resistors.

    if you want a good accuracy it's better to use very accurate resistors (0.005% or better)  

    it's a good paper to talk about it:

    http://ieeexplore.ieee.org/document/6221965/ 

    I think AMP03 or INA105 are good choices for such application.

    so you need a unity gain feedback (I'd like to call it a moderate version)

    if you want very accurate VCCS it's better to use a DC stabilized feedback. (I'd like to call it a  advanced version)

    and ...

    Regards

Reply
  • 0 on Aug 18, 2017 11:58 AM

    Thank's for your attention and recommendation

    I've studied many papers about VCCS. (almost all papers )

    it is one of the first application notes that I had studied before  

    one of the worst drawback of such circuit is the mismatch between resistors.

    if you want a good accuracy it's better to use very accurate resistors (0.005% or better)  

    it's a good paper to talk about it:

    http://ieeexplore.ieee.org/document/6221965/ 

    I think AMP03 or INA105 are good choices for such application.

    so you need a unity gain feedback (I'd like to call it a moderate version)

    if you want very accurate VCCS it's better to use a DC stabilized feedback. (I'd like to call it a  advanced version)

    and ...

    Regards

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