A low phase noise VCO for 5-GHz WiMAX/WLAN frequency synthesizer

This paper presents fully integrated CMOS LC voltage-controlled oscillator (VCO) which exhibits low phase noise and low power consumption. To reduce the of VCO, a bias filter consists of inductor and capacitor is used to suppress noise. Moreover, the source of tail current uses a memory reduced tail transistor to procure low power consumption and avoids degradation of phase noise. The VCO is designed and implemented by 0.18-μm TSMC CMOS process and achieves -100.9 and -121.5 dBc/Hz at 100-kHz and 1MHz offset respectively. The current consumption is 1.5mA with a 1.5-V power supply. A figure-of-merit of -192.1 dBc/Hz is observed by simulation.