regarding feedback in given opamp

[shivamgarg]

Hi folks...

I require help in interpreting the feedback network that is provided with the opamp. What does this feedback do?

FYI, the given opamp is amplifier with common mode feedback circuit.

Thanks.

 

[erikl]

It's a symmetrical bandpass amp,

• lower bandpass frequency=1/(2π*15Cu*100k),
• upper bandpass frequency=1/(2π*Cu*100k),
  (or 1/(2π*Cu*Rload), whichever is lower)
• bandpass differential gain=15, low common gain

 

[FvM]

Isn't it a second order high pass

high pass freq1=1/(2π*Cu*100k)
high pass freq2 =1/(2π*Cu*Rload)

?

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Plus additonal low pass with Tlp = Rsource*15Cu

 

[erikl]

Isn't it a second order high pass?

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Plus additonal low pass with Tlp = Rsource*15Cu

Yes, of course. I just wanted to give a hint for the case Rsource ≪ 100kΩ .

... and then this

upper bandpass frequency=1/(2π*Cu*100k),
(or 1/(2π*Cu*Rload), whichever is lower)

... is nonsense, sorry!