Biasing technique to improve total harmonic distortion in an ultra-low-power operational transconductance amplifier

This study presents a new technique based on large signal analysis, to enhance the total harmonic-distortion (THD) in an ultra-low-power operational transconductance amplifier (OTA). The proposed technique is used to implement an ultra-low-power gate-driven and bulk-driven OTA with high linear range. Mismatch and post-layout simulations in 0.13 μm CMOS technology demonstrate that the proposed technique can improve the THD and the dynamic range, without affecting the transconductance tuning and the common-mode control. It achieves a 183 and 640 mVpp linear ranges for gate-driven and bulk-driven OTA, and a 61.8 dB dynamic range at 0.5 V with 26.35 nW power dissipation.