An automatic switching phase-locked loop (PLL) is disclosed, including a phase detector, a charge pump generating a pump current, a band selector receiving a control voltage to produce a band selection signal and a voltage setting signal based the control voltage, a loop filter generating the control voltage corresponding to the pump current and setting the control voltage based on the voltage setting signal, and a multi-band voltage control oscillator (VCO) coupled to the control voltage and the band selection signal, selecting one of a plurality of operating bands based on the band selection signal, and providing an output signal of a frequency within the selected operating band based on the control voltage.