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TMP117: risk of not using supply decoupling cap?

Daniel Benjamin
Prodigy 120 points
Part Number: TMP117

If forced to remove the 0.1uF default bypass cap next to the TMP117, what sort of effect would this have on the temperature data streamed out at 10Hz ?

  • 0
    TI__Guru**** 244400 points
    Hello Daniel,

    A decoupling cap provides voltage stabilization when the device has a current draw. At the same time when the device is actively converting the decoupling cap provides a good measure of current for the device. Not having the decoupling cap may cause the device to be out of spec when doing temperature conversion.. What is the reason for removing the decoupling cap?
  • 0 in reply to Amit Ashara
    Prodigy 120 points
    The issue is one of physical space and an unfortunate misalignment with a test fixture. I'm trying to balance the effort to replace the bypass cap after using this fixture, with the potential improvement in data output by including the cap. This is a temporary fix, not for production.
  • 0 in reply to Daniel Benjamin
    TI__Guru**** 244400 points
    Hello Daniel,

    Without a cap I have seen temperature sensors becoming sensitive to trace lengths when driving the data lines cause the device to self heat.