Improved Amplitude Control Technique of Low Phase Noise LC VCO

In this paper, an improved amplitude control technique is presented to acquire better performance between phase noise and power consumption of LC voltage controlled oscillator (VCO). The proposed VCO with amplitude control technique is realized in 65nm CMOS process and the VCO is oscillated at 6GHz to 13GHz. The peak to peak voltage level of VCO is varied from 0.72V to 1.68V and the step size is 60mV. The phase noise of VCO oscillating at 10GHz is optimized from -110.9883dBc/Hz to -116.4206dBc/Hz at 1MHz offset while the amplitude of VCO was set from 0.72V to 1.08V. Meanwhile, additional power consumption is 14.6mW when power supply is 1.2V. The programmable amplitude provides relatively flexible configuration to determine preference in different applications.