An Enhanced Gain-Bandwidth Class-AB Miller op-amp With 23,800 MHz·pF/mW FOM, 11-16 Current Efficiency and Wide Range of Resistive and Capacitive Loads Driving Capability

A compact power-efficient class-AB Miller op-amp is introduced. It uses a simple auxiliary circuit that enhances the op-amp’s gain-bandwidth product and helps to drive a wide range of capacitive and resistive loads with high static and dynamic current efficiency. Simple Miller compensation is used to obtain stability over a wide range of loading conditions. The op-amp’s simulation and experimental results in strong inversion with
$15\mu \text{A}$
bias current and in sub-threshold with 250nA bias current are shown. Its performance is measured in terms of dynamic and static current efficiency figures of merit FOM
_CEDyn
and FOM
_CEStat
. and using the conventional small-signal figure of merit FOM
_SS
. Experimental results of op-amps fabricated in a 130nm CMOS technology are shown that validate the proposed approach.