A fully integrated 2.4-GHz receiver in a 0.18-μm CMOS process for low-power body-area-network applications

Abstract

A fully integrated 2.4-GHz receiver targeting body sensor network applications is designed in 0.18-μm CMOS technology. The receiver includes a subthreshold biased low-noise amplifier (LNA), a passive mixer, two variable gain amplifiers (VGA) and a channel select filter (CSF). Several circuit design techniques are employed in order to reduce the silicon area and the power consumption of the receiver. The measured gain and the noise figure of the LNA are 20dB and 5.2dB, respectively. These values are obtained with a very low current of 630 μA from a 1.8-V supply. By employing a digitally switched-load gain variation scheme, the gain of the first VGA and the second VGA can be varied linearly from -18.5dB to +24.5dB, and from +16dB to +54dB, respectively. Input-referred noise at maximum gain mode is less than 17nV/radicHz and the current consumption is less than 400 μA from a 1.8-V supply for both circuits. The VGAs exhibit excellent linearity in terms of gain variation and gain compression. Small silicon area is achieved by avoiding bulky passive components.