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[Funny video] Two MAX7219 chips, one from digikey, one from ebay. Unexpected result! — Parallax Forums

[Funny video] Two MAX7219 chips, one from digikey, one from ebay. Unexpected result!

CuriousOneCuriousOne Posts: 931
edited 2014-02-11 04:11 in General Discussion
https://www.youtube.com/watch?v=4sqMeePWpi8&feature=youtu.be

Here you can see two MAX7219 chips just displaying 1, 10, 100, 1000 on the LED display. Both IC are wired parallel. The one driving orange displays comes from digikey. One with red leds - from ebay. From the 1st glance, you may think that cathodes are wired in reverse with red one. No sir! If I swap these ICs, their behavour also changes - orange one starts displaying from right to left. What that's means, Maxim makes special versions of it's chips for right-to-left reading countries? :) both chips are MAX7219CNG, only MFG date code differs.

Comments

  • ctwardellctwardell Posts: 1,716
    edited 2014-02-07 08:23
    My guess is the one from ebay is a counterfeit that really puts the 'reverse' in reverse engineered...

    C.W.
  • ercoerco Posts: 20,256
    edited 2014-02-07 08:49
    It might make sense if the chip was for or from "Down Under", where seasons and coriolis acceleration are reversed.

    I suppose this thread answers the question you asked here: http://forums.parallax.com/showthread.php/153667-Why-MAXIM-IC-s-are-so-absurdly-expensive

    As usual: cheap, fast, or accurate: pick two!
  • MoskogMoskog Posts: 554
    edited 2014-02-07 09:36
    Stupid folks, don't you understand the one of them is made for hair salon equipments?
  • CuriousOneCuriousOne Posts: 931
    edited 2014-02-07 10:27
    Chips don't look like fakes, since they have all atributes of original Maxim chip. It really appears to be some specific designation series.
  • davejamesdavejames Posts: 4,047
    edited 2014-02-07 11:39
    ...that...is...really...odd...:confused:
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2014-02-07 11:59
    I'd be inclined to believe knock-off or wiring issue before I would think different version of the chip. I can't picture MAXIM IC doing that and keeping the same part number.
  • GenetixGenetix Posts: 1,754
    edited 2014-02-07 12:58
    See if the E-Bay seller will send you another batch of parts or give you a refund. It could just be a faulty part that got passed QC.
  • msrobotsmsrobots Posts: 3,709
    edited 2014-02-07 13:01
    how about turning It 180 degrees?

    Enjoy!

    Mike
  • CuriousOneCuriousOne Posts: 931
    edited 2014-02-07 13:11
    Turning around will mess with decimal points.

    Next monday I'll shoot another video, giving even more fun with that chip :)
  • jmgjmg Posts: 15,173
    edited 2014-02-07 13:43
    CuriousOne wrote: »
    What that's means, Maxim makes special versions of it's chips for right-to-left reading countries? :) both chips are MAX7219CNG, only MFG date code differs.

    Why not open the two up, and compare the die ?

    I've managed that with a metal-working file, and a scalpel.
    Once you see the bond wire flecks appear, slow down a little, and when the epoxy is very thin, it can flake off using the scalpel.
    Practice on some 10c logic parts first, if you need to.
  • MoskogMoskog Posts: 554
    edited 2014-02-07 14:08
    jmg wrote: »
    Why not open the two up, and compare the die ?

    I've managed that with a metal-working file, and a scalpel.
    Once you see the bond wire flecks appear, slow down a little, and when the epoxy is very thin, it can flake off using the scalpel.
    Practice on some 10c logic parts first, if you need to.

    Recommended outdors only, remember all the black smoke you set free..
  • GadgetmanGadgetman Posts: 2,436
    edited 2014-02-08 13:16
    Ah...
    If you release BLACK smoke, it's definitely a counterfeit part.

    The REAL stuff contains BLUE smoke...
  • CuriousOneCuriousOne Posts: 931
    edited 2014-02-11 04:11
    Fun continues, this time, genuine MAXIM part:

    https://www.youtube.com/watch?v=IDyCLAig0-8

    :D
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