Low-voltage CMOS current operational amplifier with class AB input stage

A CMOS current operational amplifier (COA) which can be operated from a minimum supply voltage of V_T+3V_DS,SAT is presented. Unlike previous low-voltage solutions operating in class A, the proposed one employs a class AB input stage that enhances slew-rate performance and provides accurate control of both quiescent currents and input bias voltage. A design example is implemented in a 0.5 μm standard technology using a 1 V supply. It exhibits a 56 dB loop gain with a gain-bandwidth product of 18 MHz. Good linearity and noise performance are also achieved