I have a question about CMOS OpAmp design. One of my Msc courses requires a project which involves design of a rail to tail OpAmp. This project should be realized both schematically and in layout. I looked for a design guide from Analog Devices, yet I couldn't find any. Is there anybody who can suggest me a good guideline to design an OpAmp?
CMOS amplifiers with rail-to-rail output stages look more like this example:
This is what is called an operational transconductance amplifier (OTA) which has a high output impedance current source based output rather than a low impedance source follower style output stage. A current source can swing much closer to to the rail than the Vgs of a follower.