A 12MHz Switched-Capacitor Relaxation Oscillator with a Nearly Minimal FoM of -161dBc/Hz

P.F.J. Geraedts, Adrianus Johannes Maria van Tuijl, Eric A.M. Klumperink, Gerhardus J.M. Wienk, Bram Nauta

    Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

    313 Downloads (Pure)


    In this work the phase noise performance of relaxation oscillators has been analyzed resulting in simple though precise phase noise expressions. These expressions have lead to a new relaxation oscillator topology, which exploits a noise filtering technique implemented with a switched-capacitor circuit to minimize phase noise. Measurements on a 65nm CMOS design show a sawtooth waveform, a frequency tuning range between 1 and 12MHz and a rather constant frequency tuning gain. At 12MHz oscillation frequency it consumes 90μW while the phase noise is -109dBc/Hz at 100KHz offset frequency. By minimizing and balancing noise contributions of charge and discharge mechanisms, a nearly minimal FoM of -161dBc/Hz has been achieved, which is a 6dB improvement over state-of-the-art.
    Original languageUndefined
    Title of host publicationProceedings of the 19th Annual Workshop on Circuits
    Place of PublicationVeldhoven
    Number of pages4
    ISBN (Print)978-90-73461-56-7
    Publication statusPublished - 29 Nov 2008
    Event19th Annual Workshop on Circuits, Systems and Signal Processing, ProRISC 2008 - Veldhoven, Netherlands
    Duration: 27 Nov 200828 Nov 2008
    Conference number: 19

    Publication series

    PublisherTechnology Foundation STW


    Conference19th Annual Workshop on Circuits, Systems and Signal Processing, ProRISC 2008


    • EWI-14988
    • METIS-255471
    • IR-65353

    Cite this