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ADS1260: Internal reference short circuit protection

Nikita Kuznetsov
Prodigy 30 points
Part Number: ADS1260
Other Parts Discussed in Thread: ADS125H02

We are using ADS1260 and ADS125H02 in our design,

For sensor exictation we are using Internal reference from the ADC.

Is it ok to put out the reference output of the ADC to the connector directly or we have to add any protection using OPAMP or something else?

The problem is the customer could accidentely short circuit the internal reference with ground.

Does the ADC Internal reference would be broken or any of ADC characteristic would changed in case of short circuit occured?

  • 0
    TI__Guru 52376 points

    Hi Nikita,

    I spoke with one of our design engineers about this question. He was able to simulate a similar reference model (not the actual one in the ADS1260) and with AVDD = 5V and REFOUT grounded there was significant current draw by the internal reference through the AVDD pin (10s of mA).

    With REFOUT grounded, any measured signal would clip at +FS or -FS assuming the internal VREF is used for the measurement because VREF = 0V under these conditions. Moreover, the IDACs would stop working when REFOUT is grounded.

    Since we don't actually perform this test it is not clear how long the device could sustain these conditions, though it is probably several hours. Therefore, it is likely that a REFOUT short would not cause permanent device damage and could be recovered by simply removing the short (as opposed to a complete device reset).

    I will again note that this information is untested and provided as-is. Please rely on this information at your own risk.

     -Bryan