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-mu m CMOS technology, uses a 5V power supply and dissipates a de 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 Omega with a maximum bipolar output current of about 15 mA, being the quiescent current in the output branch of only 140 mu A. Finally, because of its symmetrical topology, the amplifier is also well suited to be arranged in a fully-differential version.