Abstract: A clock generator with a fast settling time features a coarse-tuning circuit that is executed a single time, and a fine-tuning circuit that is executed periodically. The fine-tuning circuit sends an analog voltage to a voltage-controlled oscillator (VCO). The coarse-tuning circuit sends a load capacitance parameter to the VCO. The analog voltage and the load capacitance are used to program the VCO, which generates a clock signal. The coarse-tuning circuit and the fine-tuning circuit include registers that store the load capacitance and analog voltage information, respectively, in digital form. When switching of the oscillator occurs, the clock generator quickly produces a clock signal in accordance with the stored digital values.