An Ultra-Low Voltage, Low-Noise, High Linearity 900-MHz Receiver With Digitally Calibrated In-Band Feed-Forward Interferer Cancellation in 65-nm CMOS

We present an ultra-low voltage, highly linear, low noise integrated CMOS receiver operating from a 0.6-V supply. The receiver incorporates programmable, in-band feed-forward interferer cancellation at the baseband to obtain high linearity and low noise operation at ultra-low supply voltages. Being able to reject adjacent channel or far-out blockers, the digitally calibrated interferer cancellation improves the IIP₃ and IIP₂ by more than 13 dB and 8 dB respectively with very little impact on the receiver noise figure. As such, it breaks the trade-off between linearity and noise figure, making it possible to use a high-gain RF front-end to achieve low noise figure without affecting the linearity of the ultra-low voltage baseband circuits. The 0.6-V 900-MHz direct-conversion receiver prototype integrates a differential LNA, RF transconductors, linear quadrature current driven passive mixers, feed-forward interferer cancellation circuits, baseband variable gain transimpedance amplifiers and second-order channel-select filters. It has a nominal conversion gain of 56.4 dB, noise figure of 5 dB, IIP₃ of -9.8 dBm and IIP₂ of 21.4 dBm. The receiver operates reliably from 0.55-0.65 V, consumes 26.4 mW and occupies an active area of 1.7 mm² in a 65-nm low-power CMOS process, of which the feed-forward interferer cancellation circuits consume 11.4 mW and occupies 0.43 mm² .