HIGH CMR AND CONSTANT GAIN CMOS INPUT-STAGE WITH LOW POWER SUPPLY
Bu Dengli, Niu Xuiqing (Department of Electronic Science, Nankai University, Tianjin, 300071)
In this paper, a input stage that workes with low power supply and high CMR and approximately constant gain in the whole CMR for CMOS OPAMP is studied. To achieve high CMR, complementary N channel CMOS Dif pair and P channel CMOS Dif pair is used. To achieve approximately constant gain in the whole CMR, current switch and current mirror which compensate the current while only one Dif pair works in the CMR are used. Under the condition that the power supply is ±2V, CMR is -2V~+2V.