Design of Low Phase Noise Voltage Controlled Oscillator with Low Tuning-gain Change and Wide Linear Range

Based on 0.18 μm CMOS process, a low power low phase noise broadband VCO with low tuning-gain change constant tuning curve interval and constant output swing was presented. Switched capacitor array,varactor array with bias voltage and the tail current array was included in this VCO. The tuning range of VCO is 1.153~1.911 GHz(49.5%). The coverage of adjacent tuning curve is more than 50%. The tuning-gain of VCO is 45.5~52.7 MHz/V (13.7%). The space of adjacent tuning curve is 43.2~45.9 MHz(5.9%).The output swing of VCO is 694~715 mV(3%).The linear range of tuning curve is 0.2~1.6 V(1.4 V). At a 1.8 V supply and the center frequency 1.53 GHz, the VCO measures a phase noise of -130.5 dBc/Hz@1 MHz offset while dissipating 3.2 mA current. The FOM of the VCO is -186.5 dBc/Hz.