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ads1291 using bipolar power supply, seems shorted!

Mingling Hsu
Prodigy 110 points
Other Parts Discussed in Thread: ADS1291

hi all,

I made a simple test board using ads1291 with minimum components, it works fine when it is unipolar supplied (3.3v). But when i try to supply a +/- 1.5v bipolar supply to avdd/avss using the schematic described in the datasheet,  I found the  power supply（negative side) short circuit light blinks. It seems it is short circuited!  

What did I missed?

  • 0
    TI__Guru**** 180931 points

    Hi Minling,

    Welcome to the e2e forum!  I'm sorry to hear that you are having an issue with the ADS1291 in bi-polar supply mode.  Can you please post your schematic and we'll see if we can find something wrong?

  • 0 in reply to Tom Hendrick
    Prodigy 110 points

    hi Tom,

    Thanks for your reply, my schematic is as followed:

    The wired thing is , when i connect only avdd,gnd and avss to ads1291, it still notify short circuit (negative power side).

    Is it possible the chip has been burn? but I can't measure a short circuit using multimeter.

    Thanks for your help!

  • 0 in reply to Mingling Hsu
    TI__Guru**** 180931 points

    Hi Mingling,

    Thank you for posting your ADS1291 schematic.  Everything looks OK, so you will need to find a multi-meter that has an 'Ohm' reading capability and start probing around your printed circuit board to see if you can find any shorts.  

    It might be possible that you've burned up the chip, but without knowing exactly what was going on at the initial power up, it's hard to make that conclusion.  When powering up a circuit for the first time, you should always current limit your power supplies to prevent catastrophic damage to the parts on your board.