A high-frequency phase-compensation fractional-N frequency synthesizer

A new type of high-frequency fractional-N frequency divider with a phase compensation technique is developed, which can operate for frequencies ranging from 1 GHz to 2.5 GHz, and achieve a divide ratio of (256-271) + (f/16). The on-chip phase compensation by a delay-locked loop (DLL) is adopted to reduce the fractional spurs in the fractional-N frequency synthesizer. The fractional-N synthesizer is simulated using a 0.35- /spl mu/m standard CMOS technology and the power dissipation is about 70 mW under the supply voltage of 3.3 V.