WIDEBAND LOW PHASE NOISE DIGITALLY CONTROLLED OSCILLATOR USING SWITCHED INDUCTORS

摘要

A digitally-controlled oscillator (DCO) is provided. In one aspect, the DCO includes a resonant tank that can include multiple inductors and multiple metal-oxide-semiconductor (MOS) transistors. The resonant tank can include a first circuit connected between a first pair of inductors, a second circuit connected between a second pair of inductors, a third circuit connected between a third pair of inductors, and a fourth circuit connected between a fourth pair. Each of the third and fourth circuits can include a capacitor and a switching element. Each of the first and second pair of circuits include an inductor arranged in parallel with a respective switching element. Each of the third and fourth pair of inductors can include an inductor in common with the first pair of inductors and another inductor in common with the second pair of inductors. The fourth pair of inductors can be different from the third pair of inductors.