Modifications of a Dynamic-Logic Phase Frequency Detector for extended detection range

This paper presents two modified architectures of a Dynamic-Logic Phase Frequency Detector (PFD) which eliminate the blind-zone problem. The PFDs have linear phase-frequency characteristics for the input phase difference outside of the blind-zone, and constant phase-frequency characteristics for the phase difference inside the blind-zone. The proposed new PFD architectures extend the detection range and eliminate the polarity reversal issue of the output. The circuits have been designed in 0.13µm CMOS technology and the simulation results have demonstrated a detection range improvement in comparison to previously existing solutions.