A differential variable gain SiGe BiCMOS LNA design using current splitting and feedback techniques

Abstract

A differential variable gain low noise amplifier (DVGLNA) using the 0.35 /spl mu/m 3P3M SiGe BiCMOS process is described in this work. The differential LNA with gain control and high linearity has been developed for WCDMA applications. Using this gain control topology, differential variable gain LNA remains its input and output return loss in both high gain and low gain mode. The circuit measurement is performed by using a FR-4 PCB test fixture. The differential LNA achieves gain of 16.5 dB, noise figure of 2.1 dB, the third-order intercept point of -2 dBm, and the gain control range of 11 dB.