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DAC8563: DAC856xT power on voltage confirmation

Theo Meyer
Prodigy 85 points
Part Number: DAC8563

Hi,

Could you please confirm that the DAC8563T DAC default output voltage after power on is 0V? It is specified that at reset, the reference is set to external by default (which would be 0V if no external reference is used) and the gain is 1 by default. Since the part reset DIN to mid scale, I assume I would have an initial output voltage of Vref/2 = 0V / 2 = 0V. Am I right?

Is it possible to set up the DAC so that it defaults to 2.5V at power on? I would like to have a +/-5V output using an opamp as described in the following TI verified design circuit http://www.ti.com/lit/ug/slau525/slau525.pdf but I need to ensure the output is 0V at power on.

Thanks

  • 0
    TI__Genius 14220 points
    Hi Theo,

    Thank you for your query. I am looking into it. Will get back by tomorrow.

    Regards,
    Uttam Sahu
    Applications Engineer, Precision DACs
  • 0 in reply to Uttam Sahu
    TI__Genius 14220 points
    Hi Theo,

    My apologies for being unresponsive for so long. I was completely occupied for last couple of weeks. if you look at the first page of the datasheet, it says "The DACxx62T devices incorporate a power-on-reset circuit that ensures the DAC output powers up and remains at zero scale until a valid code is written to the device, whereas the DACxx63T devices similarly power up at mid-scale". It is also specified in section 8.3.3.2. However, you are right that as the external reference is enabled by default, the output will depend on whether the external reference is on or not.

    If you are using the TI design circuit, the output will be at 0V because the internal reference will be off and DAC output will be at 0V due to absence of external reference.

    Hope I have answered your question.

    Regards,
    Uttam