关键词: 相频检测器, 脉冲宽度, 反馈延时

Abstract: The paper introduces feedback delay of phase frequency detector,and illustrates mismatching between effective pulse width and clock period leads to phase detecting risk.The risk seriously influences the requirement of charge pump PFD design.The major factor is how to control pulse width and make a correct setup time to reduce this risk.The paper then explores the simulation data with the test bench of UMC 40nm foundry,finally pointsoutthe importance offeedback delay with PFD.

Key words: phase frequency detector, pulse width, feedback delay