Novel wideband low phase noise CMOS LC VCO

In order to solve the problem between phase noise and tuning band, a novel VCO was designed on the foundation of the combination of switching-capacitance and MOS varactor. In addition, LC noise-filter was added in the tail current source to lower phase noise further more. The circuit was designed in TSMC 0.18um CMOS process, and simulated by the SpectreRF in Cadence. Under supply voltage of 1.8V, the center frequency of the VCO was 1.8G, the output frequency ranged from 1.430G to 2.134G, and the tuning range was up to 37%. Phase noise was −131dBc/Hz @1MHz and the static current of the circuit was 5.2mA.