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open loop gain and capacitors

akbarza

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hi
in attached file (in found this file from net)in page 4 is written:
To reduce open-loop gain, resistors can be replaced
by capacitors [Fig. (a)]


why open loop gain must be reduced?
and how replacement of capacitores does reduce open loop gain?
thanks
 

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LvW

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hi
in attached file (in found this file from net)in page 4 is written:
To reduce open-loop gain, resistors can be replaced
by capacitors [Fig. (a)]


why open loop gain must be reduced?
and how replacement of capacitores does reduce open loop gain?
thanks
I must admit - I do not understand the quoted sentence. More than that, on page 2 we read:
"R2 heavily drops open-loop gain".
My question: How can a feedback resistor reduce open-loop gain of the amplifier?

In my opinion, both sentences are misleading....
 

sutapanaki

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I think, It is probably a typo. They talk about reducing the loop gain by having feedback resistors. The loop gain is reduced because the CMOS opamp is actually and OTA or because in CMOS you can make output stages with still some finite output resistance and loaded by the feedback resistors, the loop gain will drop from ideal. Caps don't load it in DC.
 

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