An Interference-Robust Reconfigurable Receiver With Automatic Frequency-Calibrated LNA in 65-nm CMOS

Abstract

An interference-robust reconfigurable receiver in 65-nm CMOS is presented. The front end is split into a low-band (LB) RF path (0.1–1.5 GHz) and a high-band (HB) RF path (1–5 GHz). By utilizing a harmonic recombination technique, the LB path could reject the third /fifth-order harmonic interferences. A tunable narrowband dual-feedback common-gate low-noise amplifier (LNA) with $LC$ resonant load provides second-order bandpass filtering to reject the harmonic interferences in the HB path. The RF high-Q bandpass filtering based on the voltage-mode passive mixer and the current-mode low-pass filter in the analog baseband improves the receiver’s resilience to out-of-band interferences. A novel power-detection-based automatic frequency calibration technique is proposed to calibrate the operating frequency of the LNA in the HB path and overcome the effects of process, voltage, and temperature variations. The presented receiver has been implemented in a 65-nm CMOS and consumes 20–76-mW power from 1.2-V power supplies, with a core die area of 5 mm2. The measured results show that the receiver can tolerate −5-dBm interference with 16-dB noise figure (NF) and achieve 95–105-dB maximum conversion gain and 1.7–8-dB NF over 0.1–5 GHz. It also achieves an average harmonic rejection (HR3)/HR5 of 61/68-dB, +7.1/+14.4 dBm in-band/out-of-band input third-order intercept point (OB-IIP3), +71.2-dBm OB-IIP2, and 58.1-dB-image rejection, after the digitally assisted calibrations. The system-level measurements show that the presented receiver achieves 2.1% error vector magnitude (EVM) for 850-MHz Global System for Mobile Communication signals and 5% EVM for band 42 time division duplexing-local thermal equilibrium (LTE) signals, respectively.