A 0.5V body driven pseudo-differential OTA for low voltage & low power applications

A body driven pseudo-differential OTA for low power and low voltage applications is designed in 250nm twin-well CMOS. Partial positive feedback is used to enhance the DC gain for the OTA. At the same time the output resistance of the OTA is also enhanced with the help of simple circuitry. Operations of the OTA are analyzed theoretically and confirmed with the simulation. The simulated DC gain is found to be 24dB and UGB of 330 kHz and Phase Margin of 80°. The input referred noise is 60uV/√Hz, Slew Rate 12V/uSec for load of 1pF and 10kΩ. It can achieve full swing of 100mV_p-p around an output common mode voltage of 250mV. The designed circuit is simulated using T-Spice and BSIM 3v3 model. The power dissipation of the proposed OTA is 6.4μWatts.