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ads1110

siauhwa ong
Expert 1510 points
Other Parts Discussed in Thread: ADS1110, ADS1113

Hi,

I just wondering what will happen if one of the input pin of ADS1110, let  say, pin In+, if floating ?

In other word, what does the converter see if one of its differential input is floating (not connected to anything)

What will the output of conversion ?

Thank you

  • 0
    TI__Guru** 112895 points

    Hi Siauhwa,

    Ideally if both of the input pair are floating the result would be near 0V.  A single floating analog input could be any value.  The input is switched capacitor, so it may drift to some value over time or be affected by environmental noise. 

    If you are thinking in terms of sensor open detection, you would not likely see the same outcome from part to part or lot to lot due to variation in production.  In this case you would be better to provide a weak pull-up (or pull-down) to the input.

    Best regards,

    Bob B

  • 0 in reply to Bob Benjamin
    Expert 1510 points

    Hi Bob,

    Thanks for the explanation.

    By the way, is there any TINA or similar software that I can use to simulate ...?

    Thank you

  • 0 in reply to siauhwa ong
    TI__Guru** 112895 points

    Hi Siauhwa,

    Unfortunately we do not have a simulation model.  You could take the information from the ADS1110 datasheet and create an impedance model based on the information on page 3 for differential input impedance and common-mode input impedance.  If you require higher input impedance you can take a look at the ADS1113.

    Best regards,

    Bob B