op-amp capacitance

[myhrrhleine]

I was wondering.
has anyone determine the distortion of on board compensation capacitors?
Do they effect the overall performance of ICs and distortion performance?

 

[rayma]

has anyone determine the distortion of on board compensation capacitors?
Do they effect the overall performance of ICs and distortion performance?

Do you mean internal to the op amp? That depends on the op amp.
Externally, COG/NPO types are normally used, so not much of a problem there.

 

[myhrrhleine]

Yes, I mean the internal compensation capacitor. I am wondering if external compensation would improve things.

 

[rayma]

Yes, I mean the internal compensation capacitor. I am wondering if
external compensation would improve things.

Usually the internal capacitor is a fixed part of the circuitry.
The technology used for the internal capacitor does vary among the
various op amps. Perhaps SW can mention some of the types used.
In some early op amps, the capacitor was formed by a reverse biased diode.

 

[davidsrsb]

..In some early op amps, the capacitor was formed by a reverse biased diode.

And lots of 2nd harmonic distortion, but then the transistors have the same problem with capacitance, Ft and hfe

 

[abraxalito]

ISTM the major problem with the Ccomp isn't its distortion, rather its customary connection to the -ve power rail of the opamp.