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hooman14
Associate II
February 14, 2011
Question

DAC output has 60 mv of offset with Ouput buffer disabled

  • February 14, 2011
  • 3 replies
  • 1051 views
Posted on February 14, 2011 at 21:08

DAC output has 60 mv of offset with Ouput buffer disabled

    This topic has been closed for replies.

    3 replies

    hooman14
    hooman14Author
    Associate II
    May 17, 2011
    Posted on May 17, 2011 at 14:24

    Any thoughts? suggestions? would appreciate the help.

    Thanks!

    hooman14
    hooman14Author
    Associate II
    May 17, 2011
    Posted on May 17, 2011 at 14:24

    Thanks John for your help.

    It was my output buffer. it wasn't disabled. I was setting the value to DISABLED(0) which really enables the DAC output buffer.

    silly me.

    Thanks again.

    John F.
    Associate III
    May 17, 2011
    Posted on May 17, 2011 at 14:24

    What are you using to measure this? What are you using as a ground (0V) reference? Have you grounded ALL the microcontroller GND pins? Do the GND pins measure as 0V? Do the other digital outputs GPIO etc. also have an offset? It sounds like your ground isn't good or you are using a poor reference ( such as the power supply 0V which may not be at the same potential as the 0V on the PCB ).

    and ... are you sure you're disabling the buffer? Can you test that by loading the output and enabling / disabling the buffer and looking for a voltage change?