LOW VOLTAGE CMOS OPERATIONAL AMPLIFIER CIRCUIT AND SAMPLE-AND-HOLD CIRCUIT PROVIDED WITH THE SAME

摘要

PROBLEM TO BE SOLVED: To provide an operational amplifier circuit with an enhanced phase margin in converting an operation mode and its bias circuit. SOLUTION: This operational amplifier circuit is configured by a differential input section 100, including an N-channel input section 120 and a P-channel input section 110, a loopback cascode gain stage 130, including a cascode current mirror 140 and a cascode current source 150 and a bias circuit 170 that generates a bias voltage to bias the differential input section 100 and the cascode gain stage 130 in an operating state on demand. The bias circuit 170 generates first and second bias voltages BIAS1, BIAS2 for biasing the cascode current mirror 140 and generates fourth and fifth bias voltages BIAS4, BIAS3 for biasing the N-channel input section 120 and the P-channel input section 110.