A fully integrated 5.8 GHz U-NII band 0.18-μm CMOS VCO

A fully integrated 5.8 GHz CMOS L-C tank voltage-controlled oscillator (VCO) using a 0.18-μm 1P6M standard CMOS process for 5 GHz U-NII band WLAN application is presented. The VCO core circuit uses only PMOS to pursue a better phase noise performance since it has less 1/f noise than NMOS. The measurement is performed by using a FR-4 PCB test fixture. The output frequency of the VCO is from 5860 to 6026 MHz with a 166 MHz tuning range and the phase noise is -96.9 dBc/Hz at 300 kHz (or -110 dBc/Hz at 1 MHz) with V ctrl = 0 V. The power consumption of the VCO excluding buffer amplifiers is 8.1 mW at V_DD = 1.8 V and the output power is -4 dBm.