A Low Phase-Noise LC voltage Controlled Oscillator in CMOS Technology

A monolithic LC voltage controlled oscillator(VCO) for PLL frequency synthesizer is presented.On designing the VCO,several optimizations have been added to the traditional circuit architecture,which efficiently reduces phase noise on the basis of sufficient tuning range.Using on-chip spiral inductors,the VCO was implemented in SMIC′s 0.35 μm 1P6M mixed-signal CMOS technology.Measured results show that the VCO has a tunable frequency of 3 GHz to 3.55 GHz.Phase noise in the vicinity of the center frequency(3.55 GHz) reaches-128 dBc/Hz at 600 kHz offset.The VCO operates under a supply voltage of 3.3 V and consumes 13 mA of current.