A sub-1V high-gain two-stage OTA using bulk-driven and positive feedback techniques

This paper presents the design and simulation of a fully differential two-stage operational trans-conductance amplifier (OTA) in a 0.18μm CMOS process with a 0.9V supply voltage. For this purpose, both the bulk-driven and positive feedback techniques are employed. These techniques increase the dc gain about 18.4 dB without any change in the power dissipation, unity-gain bandwidth, phase margin, and other specifications of the OTA. The simulation results show a dc gain of 73.8dB, unity-gain bandwidth of 272MHz and phase margin of 64°. The slew rate is 190V/μs and the OTA dissipates about 2.72mW from a 0.9V supply voltage.