Low-voltage high driving capability CMOS buffer used in MEMS interface circuits

A class-AB low voltage high driving capability CMOS buffer amplifier using improved quasi-complementary output stage and error amplifiers with adaptive loads is developed. Improved quasi-complementary output stage makes it more suitable for low voltage applications, while adaptive load in error amplifier is used to increase the driving capability and reduce the sensitivity of the quiescent current to process variation. The circuit has been fabricated in 0.8 /spl mu/m CMOS process. With 300 /spl Omega/ load in a /spl plusmn/1.5 V supply, its output swing is 2.42 V. The mean value of quiescent current for eight samples is 204 /spl mu/A, with the worst deviation of 17%.