A fast acquisition Phase Frequency Detector for phase-locked loops

In this paper, we present a fast acquisition, ambiguity-free phase frequency detector (PFD) design. This PFD completely eliminates the missing edge and phase ambiguity problems found in many conventional PFDs. Therefore, this PFD topology speeds up the acquisition process and improves the maximum operating frequency. A fabricated PFD operating at 556 MHz along with a 6.5 GHz phase-locked loop design in 0.25 mum SOI process confirm such advantages.