A pseudo-differential OTA with linearity improving by HD3 feedforward

This paper presents a fully balanced structure of a CMOS operational transconductance amplifier (OTA) with high linearity for frequency up to 50MHz. The proposed circuit is based on a conventional pseudo-differential structure with a third-order harmonic distortion (HD3) feedforward technique to cancel out the output 3rd harmonic component. The OTA was fabricated in the TSMC CMOS 0.18μm technology. The measurement results show the HD3 of −62dB with 0.4-Vpp 50MHz input signal and the power consumption of 0.47mW at a 1.2-V voltage supply.

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