Re: OPAMP Output stage?
Here are some remarks I have:
1) The output stage does NOT necessarily need to have large current, it really depends on your OTA topology. You can bias the output stage with relatively small DC current if you have a class AB output stage. If you have a class A output stage, however, you may have to burn more current to keep your two stage OTA stable.
2) Miller compensation is always needed when you do have a two stage OTA.
3) The main purpose of having a dedicated output stage is to drive resistive load, as you understands. Thus, it is not always necessary to have an output stage in the system. You need to figure out this soon enough before doing any opamp design.