crystal controlled oscillator

Discussion in 'The Projects Forum' started by giodelsignore, Oct 3, 2009.

  1. giodelsignore

    Thread Starter New Member

    Oct 2, 2009
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    I tried to make an oscillator using a CD4060 and a quartz crystal FOXLF018S at a fundamental frequency of 1.8432 MHz. The circuit diagram I used is the one illustrated in Fig.13 on the data sheet for the 74HC4060 by NXP Semiconductors. It doesn't oscillate. Could it be because the CD4060 is too slow at this frequency? May be it would work with the high speed version 74HC4060?
    Thank you
    Giovanni
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
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  3. Wendy

    Moderator

    Mar 24, 2008
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    I don't know where they are, but there a have been threads where people got it to work around those frequencies. It would be worth your time to do a search.
     
  4. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    From the data sheets I've looked at, the maximum internal RC oscillator frequency is <1MHz..typically 600KHz. I doubt that it's any different for the crystal setup...though they don't seem to spec' that.

    Ken
     
  5. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    The oscillator should work at 1.8 Mhz without any problems.
    See the datasheets fro more info.
    The 4060 should work upto 20 Mhz at 15 Volts
    The 74HC4060 should work upto 20 Mhz at 5 Volts.

    Greetings,
    Bertus
     
  6. SgtWookie

    Expert

    Jul 17, 2007
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    Do you have pin 12 (MR) held to a logic low level?
    Pin 10 should be at a different logic level than pin 11.

    Crystals are sensitive to shock. If you've dropped it on a hard surface from a height of a couple of feet or more, you may have broken the crystal.
     
  7. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Can you post a schematic of the crystal oscillator using the 4060 ?

    Greetings,
    Bertus
     
  8. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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  9. bertus

    Administrator

    Apr 5, 2008
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    Hello KMoffet,

    Yes, I know, but I want to know how the Topic Starter has connected it.

    Greetings,
    Bertus
     
  10. davebee

    Well-Known Member

    Oct 22, 2008
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    Crystal oscillators can be very sensitive to the values of those little capacitors in the circuit. When breadboarding oscillators, I've found that even with identical brands of crystals, sometimes the capacitors have to be adjusted to get the circuit to work properly.

    As you vary the capacitance, you may get to a state where the oscillator won't run at all, or will run if you touch part of the circuit with your finger but will not start on its own, or will start and run but runs more crystal current than it should.

    Ideally, when tuned the best, it will start on its own and will run with fairly low crystal current. This should not be all that difficult of a circuit to get working, but may need some capacitor adjusting. Increments of 5 or 10 pf might be good values to vary the capacitances at.
     
  11. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Here are two application notes on crystal oscillators.

    Greetings,
    Bertus
     
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