A Spur Suppression Technique for Phase-Locked Frequency Synthesizers

A 4.8GHz integer-N frequency synthesizer with distributed phase-frequency detectors and charge pumps moves spurious tones to higher frequencies and reduces the spur levels. PPM is used to relax the analog circuit accuracy requirement. The circuit is fabricated in a 0.18μm CMOS technology, dissipates 18mW from a 1.8V supply and suppresses sidebands by 10dB