A low-power and low-phase-noise LC digitally controlled oscillator featuring a novel capacitor bank

A monolithic low-power and low-phase-noise digitally controlled oscillator(DCO)based on a symmetric spiral inductor with center-tap and novel capacitor bank was implemented in a 0.18μm CMOS process with six metal layers.A third new way to change capacitance is proposed and implemented in this work.Results show that the phase noise at 1 MHz offset frequency is below-122.5 dBc/Hz while drawing a current of only 4.8 mA from a 1.8 V supply.Also,the DCO can work at low supply voltage conditions with a 1.6 V power supply and 4.1 mA supply current for the DCO's core circuit,achieving a phase-noise of-121.5 dBc/Hz at offset of 1 MHz.It demonstrates that the supply pushing of DCO is less than 10 MHz/V.