A filtering technique to lower LC oscillator phase noise

• 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 1.1-GHz VCOs achieve -153 dBc/Hz at 3 MHz offset, biased at 3.7 mA from 2.5 V. A 2.1-GHz VCO achieves -148 dBc/Hz at 15 MHz offset, taking 4 mA from a 2.7-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.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering (hsv//eng)

Keyword

UHF oscillators

passive filters

phase noise

voltage-controlled oscillators

Publication and Content Type

art (subject category)

ref (subject category)