High slew rate two stage A/AB and AB/AB op-amps with phase lead compensation at output node and local common mode feedback

Abstract

Class A/AB and class AB/AB two stage op-amps with very high and symmetrical slew rate are introduced. They use output dominant pole with phase lead compensation. Resistive local common mode feedback is used to achieve a class AB output stage. One of the architectures uses also a class AB pseudo-differential pair to achieve class AB operation in the input stage. Experimental results verify slew rate enhancement factors of 12 and 50 for the A/AB and AB/AB circuits respectively. This is achieved with same bandwidth and noise and very small additional quiescent power dissipation or hardware complexity.