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Designing a board with an sx48 — Parallax Forums

Designing a board with an sx48

SailerManSailerMan Posts: 337
edited 2007-10-07 14:58 in General Discussion
One quick design question, when designing a PCB Is it necessary to use a bypass capacitor on each set of VDD/VSS pins on the SX48?

Thanks,
Eric

Post Edited (SailerMan) : 10/7/2007 2:41:05 AM GMT

Comments

  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2007-10-07 07:12
    Yes. And apparently having 4 allows for smaller values which enhances response. Guenther discussed this in a thread some time ago, maybe over a year or so. Also, the radial configuration reduces RFI at higher clocking speeds. Try searching for RFI as a topic.

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  • Guenther DaubachGuenther Daubach Posts: 1,321
    edited 2007-10-07 14:58
    It is not only the bypass caps - I also highly recommend to connect all four Vdd pins to Vdd, and all four Vss pins to Vss in order to reduce the impedance of the supply traces to recude EMI. This also has the advantage that you can sink into or source from outputs the maximum allowed total current (see the data sheet for more details under "Absolute Maximum Ratings").

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