What is PPM with regards to crystal tolerances

Discussion in 'General Electronics' started by kean, Jun 22, 2004.

  1. kean

    kean Guest

    Hi,
    Looking at datasheets for crystals, they specify its tolerance as +/-
    100 PPM. What does PPM stand for and how do you calculate the
    tolerance of the crystal in terms of frequency?

    Thanks,
    Kean
     
    kean, Jun 22, 2004
    #1
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  2. kean

    Art Guest

    Parts Per Million: General reference to tolerance of the crystal frequency.
    1.00 MHZ Xtal with +-1PPM would therefore be plus or minus 1 hertz to be
    within that specific tolerance.
    "kean" <> wrote in message
    news:...
    > Hi,
    > Looking at datasheets for crystals, they specify its tolerance as +/-
    > 100 PPM. What does PPM stand for and how do you calculate the
    > tolerance of the crystal in terms of frequency?
    >
    > Thanks,
    > Kean
     
    Art, Jun 22, 2004
    #2
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  3. kean

    Externet Guest

    Hi Kean.
    PPM is parts per million.

    Is like percentage, but per million instead.

    On a ±100 ppM tolerance, means a 1 MHz crystal can be anywhere in the
    range of 999 900 Hertz to 1 000 100 Hertz.

    Miguel
     
    Externet, Jun 22, 2004
    #3
  4. kean

    Zorknob Guest

    (kean) wrote in message news:<>...
    > Hi,
    > Looking at datasheets for crystals, they specify its tolerance as +/-
    > 100 PPM. What does PPM stand for and how do you calculate the
    > tolerance of the crystal in terms of frequency?
    >
    > Thanks,
    > Kean


    PPM = parts per million

    With a +/- 100ppm tolerance, a 1MHz crystal can range in frequency
    from 999,900Hz to 1,000,100Hz. Where the crystal oscillates within
    the range is primarly a function of temperature.
     
    Zorknob, Jun 22, 2004
    #4
  5. kean

    Rich Grise Guest

    "kean" <> wrote in message
    news:...
    > Hi,
    > Looking at datasheets for crystals, they specify its tolerance as +/-
    > 100 PPM. What does PPM stand for and how do you calculate the
    > tolerance of the crystal in terms of frequency?


    100 PPM == 0.01%

    Cheers!
    Rich
     
    Rich Grise, Jun 23, 2004
    #5
  6. kean

    kean Guest

    "Rich Grise" <> wrote in message news:<UT5Cc.23892$>...
    > "kean" <> wrote in message
    > news:...
    > > Hi,
    > > Looking at datasheets for crystals, they specify its tolerance as +/-
    > > 100 PPM. What does PPM stand for and how do you calculate the
    > > tolerance of the crystal in terms of frequency?

    >
    > 100 PPM == 0.01%
    >
    > Cheers!
    > Rich


    Okay!. Thanks a lot for the help guys.
     
    kean, Jun 23, 2004
    #6
  7. kean

    Robert Baer Guest

    kean wrote:
    >
    > Hi,
    > Looking at datasheets for crystals, they specify its tolerance as +/-
    > 100 PPM. What does PPM stand for and how do you calculate the
    > tolerance of the crystal in terms of frequency?
    >
    > Thanks,
    > Kean


    Be advised that 100ppm is crappy; a good RailRoad watch does better...
     
    Robert Baer, Jun 23, 2004
    #7
  8. "Rich Grise" <> wrote in message news:<UT5Cc.23892$>...
    > "kean" <> wrote in message
    > news:...
    > > Hi,
    > > Looking at datasheets for crystals, they specify its tolerance as +/-
    > > 100 PPM. What does PPM stand for and how do you calculate the
    > > tolerance of the crystal in terms of frequency?

    >
    > 100 PPM == 0.01%
    >
    > Cheers!
    > Rich


    PPM can refer to the temperature coefficient as well, so in this case
    it's not just an absolute frequency error, but a variation with
    temperature.
    100ppm/degC will give you 0.01% change per degree C. A big change if
    you are working over a wide temperature range.

    Dave :)
     
    David L. Jones, Jun 27, 2004
    #8
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