Linearized CMOS OTA using active-error feedforward technique

Highly linear operational transconductor amplifier (OTA) is developed, using CMOS differential pair transconductors in an active-error feedforward linearization configuration. As a result, improved linearity of the differential-input two-output OTA is obtained. SPICE simulations show that for the circuit working with a ±1.25 V power supply, total harmonic distortion (THD) for f = 1 MHz at 0.4V_pp (0.8_pp) is less than -72 dB (-60 dB) in comparison to -35 dB (-20 dB) without linearization. Moreover, the input voltage range of linear operation is increased by more than 300%. Power consumption of the overall circuit is 0.94 mW.