A 2.7 to 4.6 GHz multi-phase high resolution and wide tuning range digitally-controlled oscillator in CMOS 65nm

In this paper, a digitally-controlled oscillator (DCO) with differential output and eight different phases is proposed. The DCO is based on two-path ring oscillator (RO) with cross-coupled structure. The proposed DCO structure consists of four differential stages and two 9-bit digitally-controlled current sources, which guarantee high resolution and monotonic behavior of the DCO. The circuit is simulated in 65nm standard CMOS technology. The simulation results indicate that frequency can change from 2.7GHz to 4.6GHz with 512 steps which leads to very high resolution DCO. The simulated cycle to cycle Peak-to-Peak jitter and RMS jitter in 4GHz frequency are 6.47ps and 0.53ps respectively. Power consumption at 1.2v supply, varies between 0.59mW to 1.39mW based on digital code word.