Replacement for unavailable chip

Discussion in 'The Projects Forum' started by MikeKulls, Apr 4, 2016.

  1. MikeKulls

    Thread Starter New Member

    Apr 4, 2016
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    I am trying to build a circuit I found online, I'm no expert so I like stuff where the functionality is packaged into a chip of some sort. This circuit simply produces a square wave of 153.6Khz using a chip called exo-3 or exo-3c. The chip has an internal crystal I believe so will be accurate. I cannot find this chip available anywhere (digikey, farnel, jaycar etc) except ebay from the US but postage is expensive. I can hardly find any mention of it on the internet. Is there a replacement for this chip? Is there a simple way to produce 153600Hz squarewave that will be accurate?

    Circuit is here, the clock generator is very simple, only the exo-3 and 1 cap. (did I mention I like simple? :)
    http://pinoutsguide.com/images/nissan_consult_cable.gif
     
  2. dannyf

    Well-Known Member

    Sep 13, 2015
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    " Is there a simple way to produce 153600Hz squarewave that will be accurateaccurate"

    Yes. But what's simple to others may not be simple to you and vice versa.
     
  3. SLK001

    Senior Member

    Nov 29, 2011
    1,014
    349
    It's just a crystal oscillator, with a frequency of 153.6 kHz. It most probably is a custom frequency and not a stock item. There is an 8 pin version by SEIKO on eBay right now that should work.
     
  4. MikeKulls

    Thread Starter New Member

    Apr 4, 2016
    5
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    Can you post a link? I might not be able to see it due to country.
     
  5. MikeKulls

    Thread Starter New Member

    Apr 4, 2016
    5
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    It doesn't need to be as simple as the original but would like something based on a crystal so it is accurate. Most stuff I search online is using 555 chip which I presume isn't that accurate because you can vary the frequency with a resistor.
     
  6. dannyf

    Well-Known Member

    Sep 13, 2015
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    Tons of "simple" solutions:

    1) take an oscillator at multiples of 153.6Khz and divided it down: 9.8304Mhz (=153.6*64) is a sonet oscillator and usually very accurate - typically within 1ppm.
    2) use a mcu.
    3) use a programmable pll oscillator.
    ...

    Again, without knowing what "simple" means to you, no one can be of more help to you.
     
  7. Lestraveled

    Well-Known Member

    May 19, 2014
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    Go to Digi-Key and search for "Programmable Oscillators". Digi-Key will program them for you.
     
  8. dannyf

    Well-Known Member

    Sep 13, 2015
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    another example: 12.288Mhz is a very typical frequency, and it happens to be a multiple of 153.6Khz.

    The same for 4.9152Mhz, 19.6608Mhz, .....
     
  9. SLK001

    Senior Member

    Nov 29, 2011
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  10. hp1729

    Well-Known Member

    Nov 23, 2015
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    The frequency is standard enough. What kind of package are we talking about? Would you be open to a small board that plugs in to where the chip went?
     
  11. MikeKulls

    Thread Starter New Member

    Apr 4, 2016
    5
    1
    Thanks for all the replies. I ordered the SPG8650D, it couldn't get much simpler than that.

    Dannyf, I am curious to know how you would do it by dividing the frequency of an oscillator. If you could post something I would really appreciate it.

    Thanks again.
     
  12. MikeKulls

    Thread Starter New Member

    Apr 4, 2016
    5
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    So the SPG8650D arrived. Looking at the datasheet everything has pull-up or down resistors in the direction I need. So I just supply power and out comes 153.6khz. Couldn't get much simpler than that!! Thanks everyone for the replies.
     
    ErnieM likes this.
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