Phase noise reduction techniques for voltage-controlled oscillators (VCOs)

摘要

Certain aspects of the present disclosure provide methods and apparatus for reducing phase noise in voltage-controlled oscillators (VCOs). One example VCO generally includes a first resonant circuit comprising an inductor and a first variable capacitive element coupled in parallel with the inductor; and a second variable capacitive element coupled to a center tap of the inductor and further coupled to a reference voltage, wherein the center tap of the inductor is further coupled to a voltage source.