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DAC8775: 0V output on uni-polar mode

Kuramochi Tadahiko
Guru 28715 points
Part Number: DAC8775

Hi,

My customer is evaluating the DAC8775 on EVM.

Zero code of voltage output  on uni-polar mode seems not to go well as below.

- OUTA: 0.111567V, OUTB: 0.040245V

 Input code:0x0000

 VNEG is connected to GND directly.

 Selected VOUT range: 0 to +5V

Not zero code is outputted correctly(e.g. 2.5V, 5V).

Is there any careful point to output 0V?

Please let me know if you have any question.

Best Regards,

Kuramochi

  • 0
    TI__Expert 5820 points
    Hi Kuramochi-san,

    The parameters in the EC table of the datasheet are specified with VNEG=-15V and VPOS=15V. With VNEG connected to GND the output will not have the footroom to output 0V. This can be solved by providing a negative power supply to VNEG.

    Do they plan on using the integrated DC-DC converter? If so, the required headroom and footroom will be maintained on VPOS and VNEG.

    Thanks,
    Garrett