Hi philipwang: I think all of the MOS transistor of an opa should be in saturate region, right? and the saturate region has a relation with the current that pass the MOS transistor, right?
Q11 pass the source or sink current, Q10 and Q11 should be in saturate region, so I must confirm the source or sink current. At the same time, the source or sink current has relation with the load resistance RL, so for an output signal with 2-V peak-to-peak voltage swings, the op-amp output varies from 0.5 to 2.5v, and RL is 50Ω, how can I confirm the w/l of Q10 and Q11?
Or is there have other way to confirm the w/l of Q10 and Q11?