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LT1009: single refrenece for multiplle A/Ds usage

Tsahi Tal
Prodigy 160 points
Part Number: LT1009
Other Parts Discussed in Thread: LM4040, LM4040-N

hi

Might there be any issue with connecting one voltage reference to couple (or more) A/D converters, assuming the reference is able to sink and source current?

thanks

  • 0
    TI__Expert 3835 points

    Hi Tsahi,

    Can you shed a little more light on your application, possibly a schematic or design parameters? A shunt reference is more designed to sink current to provide proper reference. The load current provided will be coming from the input .

    Ethan

  • 0 in reply to Ethan T
    Prodigy 160 points

    Hi

    Thanks for the answer.

    I wish to connect one refernce into two reference inputs of sar a2ds.

    I have strict serious pcb area constraints.

  • 0 in reply to Tsahi Tal
    Guru 140200 points
    Hi Tsahi Tal,

    as the datasheet of LT1009 does not show any specification about the behaviour with load capacitance, I wouldn't use it as a reference for an ADC, as bypass capacitance is what is usually needed at the Ref-input of ADC. Why not taking the LM4040 for this purpose? Additionally place 100n at each ref-input.

    Kai
  • 0 in reply to Tsahi Tal
    TI__Expert 3835 points

    Hi Tsahi,

    What kind of issues are you seeing? Have you tried referencing only one ADC at a time? Is it possible to share parts of the schematic?

    I do recommend using a newer part like the LM4040 or LM4040-N that shows more support for ADC applications on their datasheet.

    Is there a reason you chose the LT1009?

    Thanks,

    Ethan

  • 0 in reply to Ethan T
    Prodigy 160 points

    Hi Eithan.

    I can check other references since I don't have performance issues.

    I didn't see any erronous behavior since I am still in the conceptual design phase.

    thanks