A high-drive high-gain CMOS current operational amplifier

A novel single-input differential-output CMOS current operational amplifier is presented which provides high gain and high drive capability. The amplifier is designed with a 1.2-/spl mu/m CMOS technology, uses a 5 V power supply and dissipates a dc power less than 3 mW. Moreover, it exhibits an open-loop gain of 90 dB and a gain-bandwidth of 11 MHz. Thanks to the use of a novel class AB output stage, the proposed amplifier is able to drive a load resistance of 100 /spl Omega/ with a maximum bipolar output current of about 15 mA, being the quiescent current in the output branch of only 140 /spl mu/A. Finally, because of its symmetrical topology, the amplifier is also well suited to be arranged in a fully-differential version.