A RF CMOS band-pass tracking filter with enhanced Q and high linearity

A CMOS RF band-pass tracking filter is developed for mobile TV tuner using Gm-C filter. The linearity of the filter is improved by the internal cancellation of the IM3. The Q factor is enhanced by increasing output resistances of OTAs using the negative output resistances of the differential pairs. The resulting filter has a gain over 17dB, NF under 13dB across 50-850MHz bandwidth. The chip is designed using 65nm CMOS process, whose size is 0.65mm × 0.35mm. In-band OIP3 and OIP2 are 9.1dBm and 32.7 dBm, respectively. It has 24dB 3
^rd
harmonic rejection and maximum 11.4dB unwanted channel rejection at 6 channels offset (40MHz). Total power consumption of the filter is 16.2mW with 1.2V supply voltage.