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DAC60096: Power Sequencing

Steve Widener
Genius 9805 points
Part Number: DAC60096

I have a few questions about the DAC60096.

1. What are the problems and effects when SDI has a voltage applied and the power rails are off.

2. What are the draw backs and problems with having the 3.3V powered but not the +/-12V

  • 0
    TI__Guru 53163 points

    Hi Steve,

    1. The biggest risk is that you are violating the abs. max. table limits.  Though if the SDI input is very current limited (<5mA), then I doubt this would be a problem.

    2. This should not be an issue.  Please see below section of the PDS.  The device will simply stay in reset until DVDD is provided.

    Thanks,

    Paul

  • 0 in reply to Paul_Frost
    TI__Expert 6090 points

    Paul,

    Here are follow-on details/questions:

    Currently my 3.3V rail also enables the 2.5V rail for the DAC, will this cause problems without the +/-12V?  We currently are using multiple DACs on the same IO bus and we want to be able to drive them all with the same SDI signal without damaging the part. But we are trying to conserve power by turning off the DACs that are unused at certain times. Do you have any suggestions? We are very limited on space for this design so we won’t be able to add external parts easily.

    Please advise - thank you.

  • 0 in reply to Go Bravos
    TI__Guru 53163 points

    Hi Brad,

    The reference buffers are actually on the AVCC domain, so you could see higher current if the reference is on but VCC is off.  Is it possible to enable the reference with the AVCC as an input? 

    The DAC60096 does not offer individual channel shutdown.  You can reduce power by disabling the reference, but that would impact all the channels under the reference.  The power consumption is dominated by the resistor ladder themselves on the reference buffer output.

    I'm interested in hearing more about the opportunity.  Can you shot me an email?

    Thanks,

    Paul