A very-linear CMOS transconductance stage for OTA-C filters

Abstract

A novel CMOS differential input stage for transconductance amplifiers is presented, which combines a low noise excess factor and low input capacitance with a very good linearity. Measured distortion is on1 0.2% for a 1 Volt RMS input signal, and only 1% for a I Volt RMs input signal, on a test circuit implemented in a standard 3 pM CMOS process, using f5 Volt supplies. This results in over 85 dB of dynamic range.