An automatic frequency calibration technique for fractional-N frequency synthesizers

This paper proposes a novel automatic frequency calibration technique that can be used for fractional frequency synthesis and compatible with different reference frequencies from 8 to 40 MHz. The proposed technique has been realized in a fractional-N frequency synthesizer for digital TV RF tuners. The measurement shows this technique ensures the synthesizer to lock at the linear range of the charge pump. This work is implemented in 65nm CMOS process. The power dissipation is 26.7 mA from a 1.2-V supply voltage. The integrated noise is less than 0.9° across the frequencies from 2680 to 4020 MHz.