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OPAMP/OTA topology to drive large capacitor ?

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taofeng

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what kind of topology are suitable for driving the large capacitor load (about 100p F), and the load resistance is also varied greatly ?

Basically I want to drive it in a low speed way ?

any idea, thanks
 

using class ab output stage.
 

taofeng said:
what kind of topology are suitable for driving the large capacitor load (about 100p F), and the load resistance is also varied greatly ?

Basically I want to drive it in a low speed way ?

any idea, thanks
Click to expand...

Folded cascode single stage opamp is the best choice. It give you high gain around 60-70 dB with one stage. The dominant pole is at output and even with 100 pF, it even give better phase margin. The bigger capacitor, the more stable the system.

Another method can try...

https://www.analog.com/library/analogDialogue/archives/38-06/capacitive_loading.html
 

but when the capacitor is too large, the slew rate is the most limitation of the opamp's speed. so to drive a large capacitor ,the class ab output stage is needed
to get the large drive current

Added after 47 seconds:

but when the capacitor is too large, the slew rate is the most limitation of the opamp's speed. so to drive a large capacitor ,the class ab output stage is needed
to get the large drive current
 

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