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Correct parallel resistor value for Parallax 20MHz resonator — Parallax Forums

Correct parallel resistor value for Parallax 20MHz resonator

BeanBean Posts: 8,129
edited 2005-06-10 16:26 in General Discussion
Does anyone know, or can tell me how to determine the correct parallel resistor value for the Parallax 20MHz surface mount resonator item #250-12060 ?
I've look over the datasheet from the website, but I don't see it listed anywhere.
Thanks,
Bean.



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Comments

  • KenMKenM Posts: 657
    edited 2005-06-10 02:41
    Good question,

    You probably already saw this.
    Resonator Resistor.jpg
    855 x 427 - 79K
  • BeanBean Posts: 8,129
    edited 2005-06-10 11:00
    Right I saw that and it has both a 22K and 1M so I didn't know which one to pick.
    Maybe it's not that critical, but that is a large difference in resistance.
    Could I just use something like 100K ?
    Bean.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    "SX-Video·Module" Now available from Parallax for only $28.95

    http://www.parallax.com/detail.asp?product_id=30012

    Product web site: www.sxvm.com

    "If you keep doing what you always did, you'll keep getting what you always got."
    ·
  • Guenther DaubachGuenther Daubach Posts: 1,321
    edited 2005-06-10 15:42
    Bean,

    according to the Ubicom specs, the value of that mysterious resistor depends in the resonator type (either 1 M or 22 k). I don't know which Murata type Parallax is selling under their stock number 250-12060 but they should be able to tell you. I would try the 22 k and see if the oscillator savely starts at power-up (don't forget to test that within a certain temperature range). My experience with the 50 MHz resonator is that the parallel resistor is not that critical at all. Normally, I'm using 10 k but I never had trouble when leaving it away.

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    Greetings from Germany,

    G
  • BeanBean Posts: 8,129
    edited 2005-06-10 16:26
    When you pull-up the datasheet from the Parallax website, it is not a murata datasheet.
    Bean.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    "SX-Video·Module" Now available from Parallax for only $28.95

    http://www.parallax.com/detail.asp?product_id=30012

    Product web site: www.sxvm.com

    "If you keep doing what you always did, you'll keep getting what you always got."
    ·
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