Charge-Controlled Oscillators and Their Application in Frequency Synthesis

A tunable oscillator, whose frequency is a function of the total charge in the oscillating nodes, is introduced in this brief. Three variants of charge-controlled oscillators (QCOs) that oscillate around 3.6 GHz are presented. The figure-of-merits (FoMs) of these oscillators, obtained from simulation, are 169, 172, and 178 dB, respectively. The measured FoM of the third QCO is 179 dB. We also show that the use of a QCO in a frequency synthesizer eliminates the requirement of an explicit loop filter. Furthermore, an example of an all-digital phase-locked loop based on a QCO is shown.