raja.cedt wrote on Mar 14th, 2016, 4:25am:1. OTA/OPAMP is always depends on what kind of you have been driving. In case of LDO no matter what kind of block you design it works as VCVS, because of high impedance. You deliberately want to add some o/p stage to make to VCCS when you are driving heavy current loads.
2. O/p device, generally will be saturation contrary to what you wrote, this give's good psrr and load regulation. of course when you wanted to build a very low dropout, where you can't afford 100mV-150mV due to heavy current and supply limitation you will have to live with triode device. But as far I know no would want to deliberately keep it in triode.
Best regards,
Raj.
Thanks for the reply. I think I should have modified my first question, is it advantageous to use OTAs instead of OP-AMPS for Error amplifiers ? I have seen papers where they use OTAs as the error amplifier (Millikan, for example).
It is interesting you say that the preferred mode of operation is saturation and not linear/triode for the pass device. I thought that the pass device was used as a resistor in a voltage divider setup and so it used in the triode mode.
Could you clarify your second statement? If I want low dropout, then I use it in triode mode?