Linear range extensible Phase Frequency Detector and Charge Pump for fast frequency acquisition
A new type Phase Frequency Detector (PFD) and Charge Pump (CP) configuration with extensible linear range is presented in this paper. The proposed Linear Range Extensible PFD and CP (LRE-PFDCP) can minimize the impact of non-ideal effects caused by the limited linear range of the Conventional PFD and CP (C-PFDCP). Thus, the frequency acquisition time of the Phase-Locked Loop (PLL) implemented with LRE-PFDCP can be significantly reduced during large frequency hopping. Unlike other linear range extension techniques, the proposed LRE-PFDCP is robust and does not cause PLL unlocking. The proposed LRE-PFDCP together with a prototype PLL is designed and simulated in a 0.18µm CMOS process. Simulation results show that the PLL achieves 320MHz frequency hopping within 4µs, which is about 3.25 times faster than the same PLL with linear range extension disabled.