A 65-nm 84-dB-gain 200-MHz-UGB CMOS fully-differential three-stage amplifier with a novel Common Mode control

A single miller capacitor feedforward compensation (SMFFC) technique with a novel common mode (CM) control circuitry for fully-differential multistage amplifiers is presented in this paper. The novel alternative to control the output common-mode voltage, adding a feed-forward path to a normal common-mode feed-back (CMFB) amplifier, allows to have a very stable and wide-band regulation. A fully-differential three-stage amplifier based on this approach has been implemented in 65-nm CMOS technology. A DC-gain of 84-dB and a bandwidth of 200-MHz are achieved, driving a 25-kOmega//1-pF load. Thanks to the novel control circuitry, the CM path achieved 136-MHz bandwidth with 85-dB DC-gain. The power consumption is 10.17-mW with a 1-V power supply. It occupies 0.02-mm² of silicon area.