Design and simulation of low power operational transconductance amplifier

Abstract

In the era of portable and battery-operated devices, the need for power-efficient analog circuits has grown significantly. Operational Transconductance Amplifiers (OTAs), being integral components in analog signal processing, data conversion, and sensing applications, must be optimized to balance power consumption with performance. This work presents the design and implementation of a low-power Class-AB OTA using standard 180nm CMOS technology, targeting low-voltage, energy-constrained systems such as biomedical devices, wearable electronics, and sensor interfaces. A two-stage as well as three-stage amplifier architecture have been worked upon, enhanced by Class-AB output operation to improve drive capability and dynamic range without significantly increasing quiescent power consumption. The design incorporates Miller compensation to ensure adequate phase margin and stability across a wide range of capacitive loads. Low power operation is achieved through optimized transistor sizing and bias current selection, focusing on minimizing static power dissipation while retaining high gain and sufficient bandwidth.