A high-linearity receiver RF front-end with a high-performance 25%-duty-cycle LO generator for WCDMA/GSM applications

A fully integrated receiver RF front-end that meets the WCDMA/GSM system requirements is presented. It supports SAW-less operation for WCDMA. To improve the linearity in terms of both IP3 and IP2, the RF front-end is comprised of multiple-gated LNAs with capacitive desensitization, current-mode passive mixers with the proposed IP2 calibration circuit, and reconfigurable Tow-Thomas-like biquad TIAs. A new power-saving multi-mode LO generator with low phase noise is proposed to provide the 4-phase 25%-duty-cycle clocks. This RF front-end is integrated in a receiver with an on-chip frequency synthesizer in 0.13μm CMOS. The measurement results show that, the receiver achieves -6dBm IIP3 and at least +60dBm IIP2 for all modes and bands.