A triple-band 900/1800/1900 MHz low-power image-reject front-end for GSM

Abstract

Conventional cellular handset receiver designs place receive-band filters, usually surface acoustic wave (SAW) filters, prior to and after the low-noise amplifier (LNA). In a triple-band receiver, this amounts to six SAW filters. The device presented here also eliminates the post-LNA SAW filters, but without the excess current required by image-reject mixers. It does so through the use of passive on-chip LC image filters. This makes possible higher dynamic range with low supply current, and low noise figure while providing a greater amount of image-rejection in comparison with image-reject mixer-based solutions.