Ultra low-power rail-to-rail linear sub-threshold bulk-driven transconductor

In this paper a novel low-voltage and low-power rail-to-rail linear operational transconductance amplifier (OTA), operating in sub-threshold region is presented. The source degenerated bulk-driven input stage ensures rail-to-rail operation with enhanced linearity. To enhance its transconductance and current drive capability a regenerative feedback at input transistor's gates has been employed. The OTA operating at 0.5 V supply ensured total harmonic distortion (THD) <; -40 dB. The circuit provides 43 dB gain and 90 kHz gain bandwidth product. The Tanner EDA 15.0 simulation tool environment using 0.18 μm CMOS process technology has been used to simulate the proposed circuit. Simulation results show that with supply of one threshold order, circuit consumes 292 nA current and 146 nW power and exhibits less than -65 dB total harmonic distortions, for 100 mV(p-p) signal at 200 Hz frequency in its unity gain configuration.