Abstract: A phase-locked loop including a phase-voltage conversion unit, a calibration unit, and an oscillation feedback unit is provided. The phase-voltage conversion unit receives a reference signal having a first frequency and a first phase, and a first feedback signal having a second frequency and a second phase, and produces a first adjusting signal based on the first frequency, the second frequency, and a phase difference between the first phase and the second phase. The calibration unit receives the reference signal and the first feedback signal, and produces a second adjusting signal based on a frequency difference between the first frequency and the second frequency through a binary search operation. The oscillation feedback unit receives the first adjusting signal and the second adjusting signal, and has a controllable capacitor array controlled by the second adjusting signal for producing a second feedback signal having a third phase locked to the first phase.