A 5 GHz fast-switching CMOS frequency synthesizer

A 5 GHz PLL-based frequency synthesizer for wireless LAN applications is presented in this paper. The proposed PLL is designed using 0.25 /spl mu/m CMOS technology with 3.3 V power supply. The enlarged VCO tuning range gives extra bandwidth to achieve a reduced locking time. The buffer amplifier provides additional gain to compensate the smaller VCO output amplitude level. The phase noise at 1 MHz offset is -120 dBc/Hz, and the power consumption is 30 mW.