Fast and Efficient Integrated Circuits

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 0.010mm2 and drawing 23 μA of static current. Under a capacitive load of 25 pF, the design achieves an open-loop DC gain of 80.5 dB, gain-bandwidth of 10.7 MHz, slew rate of 202 V/μs, and phase margin of 60  in the unity-gain configuration.