A High Slew Rate, Low Power, Compact Operational Amplifier Based on the Super-Class AB Recycling Folded Cascode

This work demonstrates the first application of the super class-AB recycling folded cascode in an op-amp. Usage of adaptive biasing and local common mode feedback enhance gain-bandwidth, slew rate, and power efficiency. Class-AB control is achieved using RC lag compensation. Simulation results from layout extraction highlight the design’s strengths for applications requiring high bandwidth and low power while driving capacitive loads. The op-amp is implemented in a 180nm CMOS process, occupying an area of 0.010mm ² and drawing 23µA of static current. Under a capacitive load of 25pF, the design achieves an open-loop DC gain of 80.5dB, gain-bandwidth of 10.7MHz, slew rate of 202V/µs, and phase margin of 60° in the unity-gain configuration.