A 22-mA 3.0-dB NF direct conversion receiver for 3G WCDMA

A 2-GHz single-chip direct conversion receiver achieves a 3.0-dB double-sideband noise figure, -14-dBm IIP3 and +17-dBm IIP2 with 60-mW power consumption from a 2.7-V supply. The receiver is targeted for the third generation UTRA/FDD WCDMA system. The low power consumption has been achieved with a proper partitioning and by avoiding buffering between blocks. In the differential RF front end, current boosted quadrature mixers follow the variable-gain low-noise amplifier. At the baseband, on-chip ac-coupled highpass filters are utilized to implement amplification with variable gain having small transients related to gain steps. The outputs of the analog channel selection filters are sampled directly by the two single-amplifier 6-bit pipeline A/D converters. The spurious tones due to the feedthrough of clock harmonics to the RF input increase the noise figure less than 0.1 dB. The receiver has been fabricated with a 0.35-μm 45-GHz f_T SiGe BiCMOS process