Patent ID: 7746182

Claim:
An apparatus comprising: a voltage controlled oscillator (VCO) having a plurality of switchable capacitors and a voltage controlled adjustable capacitor; and a calibration engine having a reference frequency input that receives a reference signal, a VCO input that is coupled to VCO so as to receive an output from the VCO, and a calibration word output that is coupled to each of switchable capacitors wherein the calibration engine includes: a digital binary search circuit that is coupled to the reference frequency input, the VCO input and the calibration word output, wherein the digital binary search circuit generates at least a portion of a calibration word that is provided to the calibration word output; and an analog tuning circuit that is coupled to the reference frequency input, the VCO input, and the calibration word output, wherein the analog tuning circuit generates a least significant bit (LSB) of the calibration word.