A new CMOS buffer amplifier design used in low voltage MEMS interface circuits

To achieve low voltage high driving capability with quiescent current contr ol, a class-AB CMOS buffer amplifier using improved quasi-complementary out put stage and error amplifiers with adaptive loads is developed. Improved q uasi-complementary output stage enables it more suitable for low voltage ap plications, while adaptive load in error amplifier is used to increase the driving capability and reduce the sensitivity of the quiescent current to f abrication process variation. The circuit has been fabricated in 0.8 mum CM OS process. With 300 Omega load in a +/-1.5 V supply, its output swing is 2 .42 V. The mean value of quiescent current for eight samples is 204 muA, wi th the worst deviation of 17%.