Phase frequency detectors for fast frequency acquisition in zero-dead-zone CPPLLs for mobile communication systems

This paper introduces a new-type phase-frequency-detector (PFD) for charge pump phase-locked-loops (CPPLLs). As the PFD is configured to separate the reset part and the delay part independently, the input signal edge data, which arrive during an added delay to remove dead-zone, are not lost and do not output the wrong information, resulting in faster locking property. The experimental results of the proposed PFD show the reduced frequency acquisition time by about 30% compared with the conventional PFD in the case of 70MHz voltage-controlled-oscillator (VCO) frequency hopping for PCS mobile applications. The PFD is designed and simulated by SPECTRE and the prototype, together with a frequency synthesizer, has been fabricated in a 0.5/spl mu/m BiCMOS technology.