A highly linear pseudo-differential transconductance

This paper presents a pseudo differential, fully balanced fully, symmetric CMOS Operational Transconductance Amplifier (OTA) with inherent common mode detection which shows a very linear behavior at frequency around 10.7 MHz. A proposed feedback circuit helps to linearize the output while keeping the output voltage controllable. The OTA linearity behavior is measured in a unity voltage gain configuration which is the worst case Gm-C,filter realizations. Measurement results show a HD3 of -80dB at 10.7MHz with 1-Vp-p input signal. Two tone intermodulation measurement result shows 70dB from 1MHz tip to 10MHz. The OTA is fabricated in AMI 0.5mum CMOS process and consumes 6mA current drawn from a +/-1.65V power supply and occupies a small area of 1 18mum * 160mum.