A merged structure of LNA & sub-harmonic mixer for multi-band DCR applications

A merged structure of variable gain LNA and sub-harmonic mixer is designed for multi-band direct conversion receiver (DCR) applications with a 0.18 /spl mu/m CMOS process. The circuit uses inductive peaking loads to increase the 3dB-bandwidth and achieves 22.7/spl sim/32dB conversion gain, 2.8/spl sim/4.1dB DSB NF, -10.5/spl sim/4.1dBm IIP3 and 5/spl sim/17.3 dBm IIP2 from a 800 MHz to 2.4 GHz input range. The variable gain range is 11.5 dB at 2.1 GHz and typical LO to RF isolation is less than -50 dBm, and DC offset voltage is less than 10 mV. The overall power consumption is 17 mW with a 1.8 V supply voltage and the chip size is 2.3 mm/spl times/1.2 mm.