A CMOS OTA with extremely large DC open-loop voltage gain

Abstract

The DC open-loop voltage Gain is a very important specification for amplifiers. In order to increase this specification, in this paper, we have proposed an improved folded cascode gain boosted amplifier (improved FCGBA) which has extremely large DC open-loop voltage gain. Compared to traditional FCGBA, this novel structure needs only one auxiliary amplifier, so it is energy saving. Finally, with SMIC 0.18µm CMOS process of 1.8V supply and Hspice simulator, a corresponding amplifier with a capacitor load of 1.6pF is designed. Its voltage gain is 153dB; unit gain bandwidth is 1.91GHz; phase margin is 64°; 0.01% settling time is 2.36ns; and the power dissipation is only 12.9mW. This result confirms the validity of this new structure.