A 0.3-V Pseudo-Differential Bulk-Input OTA for Low-Frequency Applications

TLDR: This paper presents an ultra-low-voltage high-performance bulk-input pseudo-differential operational transconductance amplifier for low-frequency applications and uses the amplifier to design a tunable second-order Gm-C low-pass filter.

Abstract: This paper presents an ultra-low-voltage high-performance bulk-input pseudo-differential operational transconductance amplifier for low-frequency applications. The proposed amplifier is designed using standard 65-nm CMOS technology and powered from 0.3-V supply with a stand by current consumption of 170-nA. Post-layout simulations with a load capacitance of 5 pF have been performed to validate the performance of the proposed amplifier. The proposed amplifier exhibits a DC gain of 60 dB and a phase margin of 53 $$^\circ $$ at unity gain frequency of 70 kHz for a load of 5 pF. The proposed OTA has shown improvement of five times and more than 2.5 times in small-signal and large-signal performance, respectively, when compared to the state of the art. In addition, the proposed transconductance amplifier is used to design a tunable second-order $$G_m{\text {-}}C$$ low-pass filter. Simulation results show that tunable cutoff frequency is varying from 4 to 190 kHz which is obtained by varying the input-stage bias current from 1 to 200 nA.