A 5 GHz CMOS frequency synthesizer with novel phase-switching prescaler and high-Q LC-VCO

A phase-locked loop (PLL) frequency synthesizer with a novel phase-switching prescaler and a high-Q LC voltage controlled oscillator (VCO) is presented.The phase-switching prescaler with a novel modulus control mechanism is much more robust on process variations.The Q factor of the inductor,I-MOS capacitors and varactors in the VCO are optimized.The proposed frequency synthesizer was fabricated by SMIC 0.13 μm lP8M MMRF CMOS technology with a chip area of 1150 × 2500 μm2.When locking at 5 GHz,the current consumption is 15 mA from a supply voltage of 1.2 V and the measured phase noise at a 1 MHz offset is -122.45 dBc/Hz.