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DAC8771: What is the gain for the voltage output for 0-5V range

Sean Sneed
Prodigy 130 points
Part Number: DAC8771

The data sheet for the DAC8771 on page 37 is given by equation 7 and the comment below it states:

"WHERE:  GAIN is automatically selected for a desired voltage output range as shown in"

But I cannot find the reference in the document.

I am looking for perhaps a table of gain values vs voltage output range setting.

Where can i find this information?

  • +1
    TI__Guru* 97635 points

    Sean,


    The output range of the DAC8771 is set by the RANGE[3:0] bits of the DAC Register (0x04) described on pages 50-51 of the datasheet. For voltage outputs, the device can be set to ranges of 0-5V, 0-10V, ±5V, ±10V, 0-6V, 0-12V, ±6V, and ±12V. The DAC code scales linearly mapping a 0x0000 code to the lowest voltage, and 0xFFFF to the highest voltage.

    With a reference voltage of 5V, the equivalent gain is set depending on the range. This GAIN is the equivalent of the scale of the full scale range from the reference voltage.

    Range 0-5V: GAIN=1
    Range 0-10V: GAIN=2
    Range ±5V: GAIN=2
    Range ±10V: GAIN=4
    Range 0-6V: GAIN=1.2
    Range 0-12V: GAIN=2.4
    Range ±6V: GAIN=2.4
    Range ±12V: GAIN=4.8

    For example, (assuming a 5V reference from equation 6) if the device is set to 0-6V unipolar range, then the output is:

    VOUT = 5V * 1.2 * (DAC code/2^16)

    If the device is set to ±6V bipolar range, the output is:

    VOUT = 6V * 2.4 * (DAC code/2^16) - 6V


    Joseph Wu