A merged gain-variable RF front-end design for a 2GHz WCDMA DCR application II

A merged LNA and sub-harmonic mixer is proposed for a 2GHz WCDMA DCR application. It adopts differential variable gain LNA to increase system dynamic range and 2/sup nd/ order linearity. To remove DC offset, which can be introduced by self-mixing problem, the proposed architecture uses sub-harmonic mixing technique. To increase RF to LO isolation, we use 0.18/spl mu/m triple-well CMOS process. The system shows 28dB and 14dB conversion gain at high gain mode and low gain mode respectively. In each case, the IIP2s are 4.5dBm and 12dBm, and IIP3s are -5dBm and 3.6dBm. The overall power consumption is less than 18mW. The supply voltage is 1.8V and over-all chip size is 2.3mm/spl times/1.2mm.