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Thread: Good news - new signal...

  1. #1
    Join Date
    Aug 2007
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    Indianapolis, IN
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    Default Good news - new signal...

    OK well I finally managed to get a TLV5618 DAC working with an Arduino board. What a nightmare that was... So I can replace my noisy old ladder DAC with a proper 12-bit one.

    So I now have a 0 - 4.9v signal coming out of a DAC, and I need to make it -5 to +5v. Does anyone have any good ideas how to do this? I tried hooking it up to the TL082 circuit I used with my ladder, but all I can get now is a constant +15v from the output...

    Strange...

    Any ideas would be greatly appreciated...

    Steve
    Attached Thumbnails Attached Thumbnails newtrace.gif  


  2. #2
    Join Date
    Oct 2006
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    Cleveland, Ohio
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    Default

    check out the schematics in the open source dac thread:

    http://www.photonlexicon.com/forums/...ead.php?t=3225

  3. #3
    Join Date
    Mar 2006
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    2,478

    Default

    Also, look up standard procedures for sound output in pro gear, DAC to differential. Mostly, just an opamp. Gain of 2, and the other input 'grounded' to a -2.5V reference. Most of those use 2.25V, but the idea is the same. Tweaking the offset of the amp should be enough to make the symmetry right if you have a -2.5V reference. Most op-amps are easy to tweak, even if they don't provide specific pins for it. Just mix the output of a preset pot divider across the supply, via a 10M resistor, into one input. Might have to modify values, but that idea will work.

  4. #4
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    Aug 2007
    Location
    Indianapolis, IN
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    Thanks, I *almost* understand - but could you draw a quick schematic of the opamp, just so I'm sure.

    I fried one of my TL082 chips today, through inexperience - it went with a very dramatic pop...

  5. #5
    Join Date
    Oct 2006
    Location
    Central Florida
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    Wink

    Quote Originally Posted by shobley View Post
    ... a very dramatic pop...
    Love, peace, and grease,

    allthat... aka: aaron@pangolin

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