Low-power, enhanced-gain adaptive-biasing-based Operational Transconductance Amplifiers

A symmetrical PMOS OTA (Operational Transconductance Amplifier) is used to build an advanced rail-to-rail amplifier with improved DC-gain and reduced power consumption. By using the adaptive biasing circuit for two differential inputs, a low stand-by current can be achieved, reducing power consumption, while the DC-gain of the proposed OTA is improved by adding a partial feedback loop. Simulation shows that the OTA has a low static power consumption of 57.6 ¿W and a high FoM of 5.13 [(V/¿s.pF)/¿W] for a load capacitor of 10 pF. The circuit is designed in a STM 90 nm CMOS process.