1.5 GHz OPAMP in 120nm digital CMOS

A high-speed operational amplifier, employing only regular-threshold devices in a 120 nm digital CMOS technology, with a two-signal-path topology, is presented. A single-stage high-frequency path allows a transit frequency of 1.5 GHz and a two-stage low-frequency path increases the DC gain to 40 dB. A new near-rail-to-rail class AB output stage is achieved with two local common-mode feedback loops.