A 2.2GHz sub-sampling PLL with 0.16psrms jitter and −125dBc/Hz in-band phase noise at 700µW loop-components power

A divider-less PLL exploits a phase detector that directly samples the VCO with a reference clock. No VCO sampling buffer is used while dummy samplers keep the VCO spur <;-56dBc. A modified inverter with low short-circuit current acts as a power efficient reference clock buffer. The 2.2 GHz PLL in 0.18 μm CMOS achieves -125dBc/Hz in-band phase noise with only 700 μW loop-components power.