A CMOS mobile TV tuner with precise RF gain control and fast locking PLL for multiband FM/T-DMB/DAB applications

A fully integrated tuner IC based on low-IF architecture is developed for triple-band FM/T-DMB/DAB applications. A precise RF gain control with 50 dB dynamic range is achieved in RF VGA by employing a capacitive ladder type attenuator. A novel coarse tuning scheme based on a RF frequency-to-digital converter allows fast and agile automatic VCO frequency calibration, leading to fast locking in PLL. Implemented in 0.13 μm CMOS, the tuner consumes 57 mA from 1.2 V supply. Measured results are NF <; 1.5 dB at the maximum gain and IIP3 >; 0 dBm with LNA bypassed. The integrated phase noise of ΔΣ fractional-N PLL is less than 1 rms degree, and the coarse tuning time is less than 2.03 μsec.