A Highly Linear Operational Transconductance Amplifier (OTA) with High Common Mode Rejection Ratio

This paper presents a highly linear Operational Transconductance Amplifier (OTA) that combines two linearization techniques, one with adaptive biasing of differential pairs and second with using of resistive source degeneration. OTA has ±0.9 v power supply and consumes 456 ¿w. Improvement of adaptive bias circuit has enhanced the CMRR to 135 dB in DC. OTA has been simulated with TSMC 0.18 ¿m technology in Hspice. The simulated third order harmonic distortion (HD3) with applying a 600 mv
_P-P
differential input, remains below -67 dB at 3 MHz frequency.