• State TI Thinks Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 2 answers
  • Subscribers 47 subscribers
  • Views 326 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DAC60504: Schematic Design Review

Priyanshu Vanigota
Prodigy 150 points
Part Number: DAC60504
Other Parts Discussed in Thread: REF3450,

Tool/software:

Hello TI,

I have attached a schematic design pdf for DAC60504 IC that also contains circuit design of REF3450 IC used for supplying 5V on VDD and VREF pins of DAC IC.

I would request to review the entire schematic and provide your valuable feedback.

 

 

Thanks & Regards

Priyanshu

DAC60504.pdf

  • 0
    TI__Mastermind 42273 points

    Hi Priyanshu,

    I suppose you calculated the input current of the VREF/VDD by adding the max VDD supply current and reference input current. You also need to consider the loads you have connected to the DAC outputs. The current sourced through the outputs will also come from VDD. Make sure the REF3450 can supply this, and make sure the REF3450 can respond to any dynamic load changes if you expect load changes on the DAC outputs.  

    What is the purpose of R61? Typically I would see a pullup used on CS to make sure communication to the DAC is blocked during startup. 

    Otherwise the DAC60504 schematic looks good to me. 

    I can forward this thread to reference team if you would like them to double check the REF3450.

    Best,

    Katlynne Jones

  • 0 in reply to Katlynne Jones
    Prodigy 150 points

    Thanks for your feedback.
    Yes, please forward this thread to the concerned team for REF3450 Review.


  • 0 in reply to Priyanshu Vanigota
    TI__Mastermind 42273 points

    Hi Priyanshu,

    Just forwarded it to them, they should respond soon. 

    Best,

    Katlynne Jones

  • 0 in reply to Priyanshu Vanigota
    TI__Genius 9410 points

    Hi Priyanshu,

    I have a couple comments:

    1. The maximum current REF3450IDBVR can source is 10mA. Please make sure the current draw from REF34 will be below 10mA. I will echo Katlynne's advice below:

    Katlynne Jones said:
    The current sourced through the outputs will also come from VDD. Make sure the REF3450 can supply this, and make sure the REF3450 can respond to any dynamic load changes if you expect load changes on the DAC outputs.

    It is not obvious to me what your total load current is, but OUT1 being a 4-20 mA loop could bring it to a point where it is too high, whether from dynamic load changes or from other typical current draw. If that is the case, you could consider adding a precision low offset op amp buffer on the output that would be able to source higher amounts of current.

    2. The maximum capacitive load for REF3450IDBVR is 10µF. The total capacitance on the output of REF3450 when adding up C19, C21, and C99 is above 10µF. I would suggest decreasing C99 to make sure the output capacitive load remains in the range of 0.1µF to 10µF. 

    Thanks,

    Jackson