文档介绍：IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 36, NO. 12, DECEMBER 2001 1921
A Filtering Technique to Lower LC Oscillator
Phase Noise
Emad Hegazi, Student Member, IEEE, Henrik Sjöland, Member, IEEE, and Asad A. Abidi, Fellow, IEEE
Abstract—Based on a physical understanding of phase-noise
mechanisms, a passive LC filter is found to lower the phase-noise
factor in a differential oscillator to its fundamental minimum.
Three fully integrated LC voltage-controlled oscillators (VCOs)
serve as a proof of concept. Two -GHz VCOs achieve 153
dBc/Hz at 3 MHz offset, biased at mA from V. A -GHz
VCO achieves 148 dBc/Hz at 15 MHz offset, taking 4 mA from
a -V supply. All oscillators use fully integrated resonators, and
the first two exceed discrete transistor modules in figure of merit.
Practical aspects and repercussions of the technique are discussed.
Index Terms—Analog integrated circuits, CMOS oscillators,
noise filtering, optimization, phase noise, radio frequency, spiral
inductors, voltage-controlled oscillators.
(a) (b)
I. INTRODUCTION
Fig. 1. Basic LC oscillator. (a) Ideal negative resistance. (b) Nonlinear negative
SINGLE-CHIP radio remains a challenging problem due resistance.
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presented in Section IV. A discussion of the resul