Patent ID: 7064622

Claim:
A circuit comprising: a differential amplifier having a differential input terminal pair and a differential output terminal pair, wherein the differential amplifier provides a differential oscillating signal at the differential output terminal pair; and an inductor-capacitor (LC) tank coupled between the differential input and output terminal pairs, wherein the LC tank comprises an inductive element coupled in parallel with a capacitive element, wherein the capacitive element comprises: a first varactor pair coupled to receive a first differential control voltage, wherein the first differential control voltage i) sets a capacitance of each varactor of the first varactor pair and ii) provides a first level of adjustment to an oscillation frequency of the oscillating signal, and a second varactor pair coupled to receive a second differential control voltage, wherein the second differential control voltage i) sets a capacitance of each varactor of the second varactor pair and ii) provides a second level of adjustment to the oscillation frequency of the oscillating signal, wherein the first and second levels of adjustment are different.