A 130M to 1GHz digitally tunable RF LC-tracking filter for CMOS RF receivers

A widely tunable RF LC-tracking filter is developed for tackling the odd harmonic mixing problem in wideband CMOS RF receivers. The filter is composed of two cascaded RLC tanks, where proposed programmable transconductor stages with built-in LPF are used. IIP3 of 127.7dBμV and input-referred noise of 20.1dBμV over signal band of 5.6MHz are confirmed by measurements. The chip, fabricated in 0.18 μm CMOS process, occupies 2.8mm
²
and draws 34–120mA from a 1.8V supply.