High Slew Rate Micro-Power CMOS OTA with Class AB Input stage - Circuits and Systems, 1997. Proceedings of the 40th Midwest Symposium on

The design of a new single stage class AB operational amplifier is presented. Amplifier incorporates an input differential pair with minimum current selector and common-mode feedback to control the tail current. It shows small-signal behavior of a simple OTA, while class AB feedback provides high slew rate when large input signals are applied. Prototype circuit was manufactured in 2pm analog CMOS process. In the quiescent mode it consumes less than 20pA of supply current. Circuit has DC gain of 70dB, slew rate of 2.5 V/ps at lOpF load and 0.9 V/ps at lOOpF load. THD is better than 90dB at 0.2 Vp.p input signal and CMRR is 11OdB.