A Pseudo-Differential OTA with Linearity Improving by HD3 Feedforward

Abstract

This paper presents a fully balanced structure of a CMOS operational transconductance amplifier (OTA) with high linearity for frequency up to 50MHz. The proposed circuit is based on a conventional pseudo-differential structure with a third-order harmonic distortion (HD3) feedforward technique to cancel out the output 3rd harmonic component. The OTA was fabricated in the TSMC CMOS 0.18 mu m technology. The measurement results show the HD3 of -62dB with 0.4-Vpp 50MHz input signal and the power consumption of 0.47mW at a 1.2-V voltage supply.