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DAC1220 24 bit DAC

Tom Burdick
Prodigy 50 points
Other Parts Discussed in Thread: DAC1220

The data sheet states that operation is from almost 0 -> 5 volts output. Actually to within 20mV of the rails. Two questions:

1 How can self calibration of offset and also full scale be accomplished internally when the output does not go to the limits, and

2 How can the device (or extra circuitry) be configured to operating over the full 0 -> 5 volts. No signals or supplies can exceed 300mV of the rails per the spec sheet.

Tom Burdick

  • 0
    TI__Guru**** 180941 points

    Hi Tom,

    The DAC1220 datasheet talks about guaranteed linearity within +/-20mV of the rails.   The output can swing 0-5V.  The 'Output' section of the data sheet (page 7) describes a method to improve linearity from the full 0-5V output range by powering the part from -0.02 to +5.02.

  • 0 in reply to Tom Hendrick
    Prodigy 50 points

    Thanks Tom,

     

    Now I need to figure out how to get such supplies. I suppose I could use a bias system using schotkey diode drop, but this brings me to the edge of acceptability. Solution 2 would be to power the 'GND' and 5.02 volt pin using  OpAmps appropriately biased. I'll need to do some experimenting.

     

    Tom Burdick