Baseband stage for WCDMA direct conversion receiver with high dynamic range and accurate temperature compensation

Abstract

A highly integrated baseband stage, which adopts a new configuration for the wideband code-division multiple access (WCDMA) direct conversion receiver (DCR), is described. The baseband stage satisfies all requirements of the WCDMA DCR and consists of opamp-RC channel select filters and variable gain amplifiers with linear-in-dB gain control. It achieves a high dynamic range of 85 dB with +/- 1.5 dB accuracy over a temperature variation from -25 to 85 degrees C, 16.5 nV/root Hz input-referred noise, +20 dBV out-of-band IIP3 and +70 dBV out of band IIP2. The baseband stage is fabricated using a 0.35 mu m SiGe BiCMOS process and consumes a total current of 11 mA/CH from a 2.7 V supply.