A rail-to-rail input/output CMOS power amplifier

A rail-to-rail amplifier that maintains a high common-mode rejection ratio (CMRR) over the whole common-mode range and has a low harmonic distortion despite the use of relatively small output devices is discussed. The circuit, which measures only 0.3 mm
²
in a 3- μm technology, has a quiescent current consumption of 600 mu A and a CMRR larger than 55 dB. It handles up to 4 nF, and can, with a 5-V supply, drive 3.8 V/sub pp/ into 100 Omega (0.1% total harmonic distortion at 10 kHz).