Design of a low-power ZigBee receiver front-end for wireless sensors

This paper describes the design of a low cost, low-power ZigBee receiver for wireless sensor networks. The receiver consists of a low-noise amplifier, a pair of down-conversion mixers, and a pair of variable-gain low-pass filters. The LNA has a single-ended input, eliminating the need for an off-chip balun, a differential output, allowing it to drive a double-balanced mixer, and it uses noise cancellation to improve its noise performance. The mixers are double-balanced passive mixers to improve the receiver linearity and decrease its power consumption and flicker noise. Finally, the filter is a third-order Butterworth G_m-C filter with a variable input transconductor to provide gain programmability for the receiver. The design is made using 130 nm CMOS technology with 1.2 V supply. Simulation results show that the receiver can achieve a sensitivity level of −97 dBm while consuming only 6 mA.