A 400-µW Low-IF IoT Receiver Front-End with Tunable Charge-Sharing Complex Filter

This work reports on a low-intermediate frequency (IF) receiver front-end for Internet-of-Things applications. An un-balanced gate-boosted common-gate low-noise amplifier is proposed with 50% lower power dissipation compared with the conventional balanced topology. Channel-selection is performed with 2 complex poles centered at 2 MHz IF. The first complex pole is embedded in the passive down-conversion mixer, enabling higher in-band voltage gain and improved frequency selectivity. Built in a 28-nm CMOS process, the proposed front-end occupies an active area of 0.175 mm
²
, it is supplied with 1 V and consumes only 400 µW, while showing a minimum NF of 6.8 dB and an out-of-band IIP
3
of -0.35 dBm. The performance meets Bluetooth Low-Energy requirements and is competitive with other sub-mW receivers.