A Current-Reused Ultralow-Power IoT LNA With a Robust Linearization Technique

This letter presents an ultralow-power (ULP) low-noise amplifier (LNA) with a robust linearization technique. A replica of the LNA's amplification transistor is integrated into the negative feedback path as an auxiliary to generate postdistortion (PD) current, where accurate process-voltage-temperature (PVT)-independent third-order distortion cancellation is achieved through constant-gain bias circuits. Furthermore, the noise figure of the proposed LNA is optimized by local-positive feedback (LPF) techniques. The increase in power due to feedback paths is minimized using a current-reused technique. Manufactured in the TSMC 65-nm process, the LNA core exhibits a gain of 18.3 dB at 2.4 GHz and power consumption of 500 \mu \text {W} at a voltage supply of 0.9 V. The proposed linearization technique improves the IIP3 by more than 5.8 dB over a wide temperature range ( -40^{\circ }\text{C} to 100 °C). At room temperature, the measured IIP3 is −0.6 dBm, and the noise figure is 3.5 dB at 2.4 GHz.