A Sub-1V, 220 μW Receiver Frontend for Wearable Wireless Sensor Network Applications

Abstract

Minimizing the dissipated power of RF transceivers is the primarily target to meet the requirements of wearable wireless sensor networks (W-WSN). This paper presents an Ultra-Low Power (ULP) receiver with RF performance exceeding the requirements of the intended application. Thanks to the highly efficient current-reuse Low Noise Amplifier (LNA), followed by a passive mixer, the single-ended 2.4 GHz RF input is down-converted to a low-IF. To generate 25% quadrature LO signals, a high-swing complementary current-reuse Class-C VCO, operating at twice the desired frequency, is followed by a frequency divider-by-two. Furthermore, complex channel selection filtering with center frequency and passband of 2 MHz and 1 MHz respectively is performed utilizing the Gm-boosted Common-Gate baseband stage immediately following the mixer. The proposed receiver is designed and simulated in 40 nm CMOS technology. The entire receiver consumes only 220 μW from 0.8 V supply voltage. It shows DSB-NF of 7.5 dB, conversion gain of 50 dB and image rejection of 20 dB. The proposed design represents almost two times better power efficiency with respect to the state-of-the-art with better or equal RF performance.