A-250mV supply-voltage 65dB-gain OTA with an enhanced bandwidth and a reduced compensation-capacitor

This paper proposes a 65dB-gain operational transconductance amplifier (OTA) with an enhanced bandwidth and a reduced compensation-capacitor. The proposed OTA expands the bandwidth and decreases the compensation-capacitor in the low-voltage bulk-driven Miller OTAs [1]–[2] by using the indirect feedback compensation method [3]. The proposed OTA was implemented using a 65nm CMOS process. In the simulation, it has a 65dB-gain and consumes 32.5nW at 250mV supply-voltage. The unit-gain frequency is expanded from 3kHz to 13kHz. The compensation-capacitor is reduced from 5pF to 0.6pF. It saves 86% chip area compared to the conventional OTA.