High-gain and high-bandwidth rail-to-rail operational amplifier with slew rate boost circuit

In this work, a high gain and high bandwidth rail-to-rail operational amplifier with slew rate boost circuit is presented. The constant gm is enhanced through a source-to-bulk bias control of an input pair. A source degeneration scheme is applied to realize an input common-mode range insensitive output stage. Several compensation schemes are applied to maintain the stability. A slew rate boost circuit can improve the output slewing. The op amp performs 100-dB dc gain, 100-MHz bandwidth and 22.5-V/us slew rate at 15-pF output load. The layout area is 593/spl times/519 /spl mu/m/sup 2/ in a 0.18-/spl mu/m CMOS process. It consumes 3.2-mW at 1.8V supply voltage.