A High-Speed, Low-Power Phase Frequency Detector and Charge-Pump Circuits for High Frequency Phase-Locked Loops (Special Section on VLSI Design and CAD Algorithms)

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In this paper, we introduce a high-speed and low-power Phase-Frequency Detector (PFD) that is designed using a modified TSPC (True Single-Phase Clock) positive edge triggered D flip-flop. The proposed PFD has a simple structure with using only 19 transistors. The operation range of this PFD is over 1.4 GHz without using additional prescaler circuits. Furthermore, the PFD has a dead zone less than 0.01 ns in the phase characteristics and has low phase sensitivity errors. The phase and frequency error detection range is not limited as in the case of the pt-type and nc-type PFDs [3]. Also, the PFD is independent of the duty cycle of input signals. Also, a new charge-pump circuit is presented that is based on a charge-amplifier. A stand-by current of the proposed charge-pump circuit enhances the speed of charge-pump and removes the charge sharing which causes a phase noise in the charge pump PLL. Furthermore, the effect of clock feedthrough is reduced by separating the output stage from up and down signal. The simulation results base on a third order PLL are presented to verify the lock in process with the proposed PFD and charge pump circuits. The proposed PFD and charge-pump circuits are designed using 0.8 μm CMOS technology with 5 V supply voltage.
社団法人電子情報通信学会の論文
1999-11-25