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DAC81416: DAC81416

Li Zhang
Prodigy 10 points
Part Number: DAC81416

Hi all,

I have a question on the voltage of REFCMP pin. As it is configured using internal reference, we got a voltage of 1.8V, isn't this supposed to be 2.5V? And when it is configrued using external 2.5V reference, this pin has a weird voltage of 770mV all so. Could you please comment if you have any ideas? Thanks a lot.

  • 0
    TI__Mastermind 30218 points

    Hi Li,

    Sanjay will take a look at this and provide a response. 

    Best,

    Katlynne Jones 

  • 0 in reply to Katlynne Jones
    TI__Intellectual 2670 points

    Hi Zhang,

    Could you please provide the DAC81416 supply voltage values (VAA, VDD, VCC, VSS and VIO) and DAC81416 page schematic design (want to make sure the reference section connectivity if it's okay)?

    Thanks,

    Sanjay

  • 0 in reply to Sanjay
    Prodigy 10 points

    Hi Sanjay, 

    Thanks for your reply. VAA=5V, VDD=5V, VCC=21V, VSS=-18V and VIO=3.3V.

  • 0 in reply to Li Zhang
    TI__Intellectual 2670 points

    Hi Zhang,

      

    1. Internal reference mode : in this case REFCMP internal design node, it can be some bias voltage.

    2. External reference mode : in this case internal reference block is powered down and REFCMP pin voltage is not defined.

      

    P.S. - let know know if this is critical for your use case and why this pin voltage is needed, i can help further on this if needed.

     

    Thanks,

    Sanjay

  • 0 in reply to Sanjay
    Prodigy 10 points

    Thank you Sanjay! So what you meant is that this node is programmable, and the default is 1.8V? Because based on the datasheet, the REFCMP pin should be 2.5V, which kinda disagrees with the 1.8V measured results.

  • 0 in reply to Li Zhang
    TI__Intellectual 2670 points

    Hi Zhang,

    No, REFCMP pin is for connecting the compensation capacitor between REF and REFCMP pin for internal reference (REF pin of device) and this is to insure the proper operation of the same. Whatever voltage comes on the REFCMP is only internal bias voltage, it does not mean that that it can be programmed. 

    Ideally, you should only be looking at the REF pin voltage (internal reference mode output), not on the REFCMP pin. 

    Could you please let me know why REFCMP pin voltage is needed and where in data-sheet is written that REFCMP pin voltage is 2.5V ?

      

    Thanks,

    Sanjay