A low power VCO using active inductor for low phase noise and wide tuning range

A low power VCO using active inductor is proposed to reduce the phase noise and to enlarge the tuning range performance. It is implemented by 0.18 um CMOS process. The main idea of the proposed VCO is to replace the active circuit of the conventional VCO with active inductors. This method can improve the phase noise performance of CMOS VCO by shifting proper zero frequency of the active inductors. Additionally, it can also improve the tuning range of the VCO because the active inductor cancels out the parasitic capacitance of the circuit. By removing parasitic capacitance which deteriorates the resonance condition, the tuning range becomes wider. The power consumption is also reduced because the proposed VCO uses active inductor without generating resistance. We obtained under 20 mW power consumption and 11% tuning range. Also, we obtained -112 dBc phase noise at 1 MHz offset frequency.