A fully-integrated 5 GHz 0.18 μm CMOS VCO for 802.11A WLAN applications

This article presents a fully-integrated 5 GHz CMOS voltage-controlled oscillator (VCO)for a U-NII band 802.11a WLAN application. The VCO core circuit uses only PMOS fabricated with the 0.18 mum 1P6M standard CMOS process to obtain better phase noise performance since PMOS has a lower 1/f noise level than NMOS. The circuit measurement is performed using an FR-4 PCB test fixture. The power consumption of the VCO, excluding buffer amplifiers, is 8.1 mW at V-DD = 1.8 V The output frequency of the VCO varies from 5860 to 6026 MHz. giving a 166 MHz tuning range. The phase noise is -95.6 dBc/Hz at a 300 kHz offset.