HELP WITH OTA WITH CLASS AB OUTPUT STAGE

[jankeza]

Hello,
I am a student and i am working on project in Analog IC. I am working on OTA with miller compensation with Class AB output stage to drive Cl= 20pF and Rl = 100 ohms. If there was no output stage second pole would be determined with cl. It would be compensated with zero( there wouldn't be 2 pole because of nulling resistor ) or with only Cc that would put wp2 after wu and make wanted PM. My question is what the impact of output stage on frequency response of whole Opamp is . Will cl even make wp2 because it is connected to output stage.

 

[D.A.(Tony)Stewart]

You want a low output impedance to drive the 100 ohm and push the pole up and out of the way while regulating easier, but that current gain still introduces a pole that will need compensation in a closed loop.

Define your design specs for BW and PM.

 

[jankeza]

We need Gain > 50dB and HBW > 50 MHz.