A Wide Input Range Subsampling Phase Detector in Subsampling Phase Locked Loop

This paper presents a new structure of the subsampling phase detector (SSPD) and charge pump in Subsampling phase locked loop (PLL). In contrast with traditional Subsampling phase locked loop (SSPLL), it has no frequency- locked loop (FLL), but has a larger frequency acquisition range. It combines SSPD with a conventional phase frequency detector/charge pump (PFD/CP) to ensure a wide operating range. A range detector is designed to distinguish the big and small phase error. When the phase error is small, the charge pump is controlled by the sampling voltage (Vsam), otherwise controlled by the output of the phase detector (PD) and charge pump (CP).