A Single-VCO Fractional- $N$ Frequency Synthesizer for Digital TV Tuners

A single-voltage-controlled-oscillator (VCO) fractional-N frequency synthesizer is designed for Advanced Television Systems Committee, Digital Video Broadcasting-Terrestrial, and Integrated Services Digital Broadcasting-Terrestrial digital television tuners. This frequency synthesizer can cover all the frequency bands for all three standards with only one VCO, and thus, the chip area as well as the power consumption can be greatly reduced. Different channel spacing requirements can be fulfilled by fractional synthesis. A dynamic frequency calibration loop is also used to automatically choose the coarse setting of the VCO. The synthesizer was fabricated in a standard 0.13-μm complementary metal-oxide-semiconductor process and draws 14 mA from a 1.2-V supply. The measured phase noise is lower than -80 dBc/Hz from 1 to 100 kHz offset and -100 dBc/Hz at 1 MHz offset. The active area of the frequency synthesizer is smaller than 0.54 mm².