All-Synthesizable 5-Phase Phase-Locked Loop for USB2.0

A 5-phase phase-locked loop (PLL) for USB2.0 applications was implemented by using an all-synthesis technique. The length of the time-to-digital converter for the fine phase detector was halved by the operation of a coarse phase detector that uses 5- phase clocks. The maximum time difference between the rising edges of two adjacent-phase clocks was 6 ps at 480 MHz. The PLL chip in a 65-nm process occupies 0.038 mm², consumes 4.8 mW at 1.2 V. The measured rms and peak-to-peak output jitters are 8.6 ps and 45 ps, respectively.