Quad-NMOS cross-coupling for linearity enhancement in high frequency continuous-time OTA-C filters with IM3 below −70 dB

Abstract

This paper presents a technique to cancel nonlinearity in operational trans-conductance amplifiers for continuous-time high frequency (OTA)-C filters. The OTA's trans-conductance can be tuned from 40 to 177 μA/V, consuming 8.09 mW power at 40 μA/V with -77 dB IM3 at 25 MHz. Third-order inter-modulation components remain below -70dB up to 50 MHz trading-off with power consumption. The IM3 for a 8.445 MHz low-pass second-order filter implementation is -76.2 dB. The design works at the supply voltage of 3.3 V. The results presented here correspond to the designs simulated in Cadence using PDK 90nm technology library.