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HDC1000 Out of Tolerance

Jeremy Corkran
Prodigy 55 points
Other Parts Discussed in Thread: HDC1000, HDC1080

My company has been running product using the HDC1000 and finding the sensors to be 10-20% low on humidity, despite follow the manufacturing guidelines in 9.3.1. The reflow temperature has not peaked above 250C and reflow time is 60sec or less. The solder paste used is a SAC305 alloy along with a no-clean flux.

In 9.3.2, the PDF states the sensor will slowly settle when exposed to ambient temperature. Approximately how long does the sensor take to stabilize in ambient conditions? Are we talking hours, days, months?

I have read other posts about the issue and it seems the stock answer is to swap to the HDC1080. This is a disappointing response since it is not a drop in replacement and will require more investment in board and housing changes. Please help us in getting our current inventory of HDC1000 to work correctly.

Jeremy

  • 0
    TI__Expert 5145 points

    Hi Jeremy,

    the time for recovering from the measurement shift after soldering depends from the PCB store conditions:

    - at 30°C/40%RH the HDC1000 needs months to recover from a -15% offset;

    - at 45°C/60%RH the HDC1000 needs approximately one week;

    - at 85°C/85%RH the HDC1000 needs 12 hours.

    If possible, we strongly recommended to perform a re-hydration at 85°C/85%RH for12 hours.

    Best regards,

    Carmine

  • 0 in reply to Carmine Iascone
    Prodigy 55 points
    Carmine,

    We performed the re-hydration procedure to 300 boards and it produced no change at all. They are still reading the same as the boards that were not re-hydrated. What is the next step?

    Jeremy
  • 0 in reply to Jeremy Corkran
    TI__Expert 5145 points

    Hi Jeremy,

    This is not the expected behavior.

    First of all could you please double check the datecode of your devices? They should be dated 1527 or later. The datecode is available in two locations,

    1.    The label on the box/Reel.  
    2.    The physical marking on the device:

    Do you confirm that you performed the recommended re-hydration procedure (85°C, 85%RH, 12hr)? How long did you wait, after the re-hydration, before to perform your retest? 

    Could you please share with us your test result? If it is possible, we would like to see %RH and T results of some of your boards, compared with your reference sensor (RH and T).

    I look forward to your reply.

    Best regards,

    Carmine

  • 0 in reply to Carmine Iascone
    Prodigy 55 points
    Carmine,

    The dates for the stock are 1536, 1540, 1544, and 1549. The boards were spun on Feb 10 and the hydration procedure was performed on Wednesday (85°C, 85%RH, 12hr). The boards were tested on Thursday. We don't have the actual readings written down, just the humidity offset. Below is the information I currently have. Let me know if you need the exact numbers. The testing is done in a factory controlled environment (~73F).

    -14
    -15
    -15
    -15
    -14
    -14
    -15
    -14
    -14
    -14

    Jeremy
  • 0 in reply to Jeremy Corkran
    TI__Expert 5145 points
    Hi Jeremy,
    Yes, if can provide to us the test results is better. We would like to know what is the value for %RH and T that your reference is reading when your boards show an error of -15. We are also interested in the error in Temperature, if present. And it is possible, we would like to see the comparison of the output data before and after the re-hydration.
    It is better is you can share with us as much information as possible on your system, so that we can identify the origin of your issue. We are very confident regarding the recommended re-hydration procedure, because we have the evidence that it worked with several customers.

    Thanks in advance for your reply.
    Best regards,
    Carmine
  • 0 in reply to Carmine Iascone
    Prodigy 55 points

    We don't have records from before the re-hydration, but we do have units from that build that were not included in the re-hydration. I've also attached the reflow graph.

    Hydrated Units
    HDC1000 Test Meter Difference
    Temp Celcius RH% Temp Celcius RH% Temp Celcius RH%
    25.2 43.6 25.1 54.1 0.1 -10.5
    25.1 42.4 25.1 54.6 0 -12.2
    25.1 44.1 25.1 54.3 0 -10.2
    25.1 44.9 25.1 54.8 0 -9.9
    24.9 43.8 25.1 54.2 -0.2 -10.4
    25.1 44.8 25.1 54.9 0 -10.1
    25.5 43.1 25.1 54.5 0.4 -11.4
    25.1 44.4 25.1 54.7 0 -10.3
    25 43.9 25.1 54.7 -0.1 -10.8
    25 45.3 25.1 55 -0.1 -9.7
    Control Units
    HDC1000 Test Meter Difference
    Temp Celcius RH% Temp Celcius RH% Temp Celcius RH%
    25.1 39.6 25 55.5 0.1 -15.9
    24.7 41.6 24.9 55.7 -0.2 -14.1
    24.8 41.9 24.9 56.6 -0.1 -14.7
    24.8 41.9 24.9 56.4 -0.1 -14.5
    24.7 42 24.8 56.3 -0.1 -14.3
    24.8 40.7 24.7 56.8 0.1 -16.1
    24.7 42.2 24.6 56.9 0.1 -14.7
    24.7 43.9 24.6 56.9 0.1 -13
    24.6 42.6 24.5 57.2 0.1 -14.6
    24.3 42.4 24.4 58 -0.1 -15.6

  • 0 in reply to Jeremy Corkran
    Prodigy 55 points

    We are also trying to return 24k of the HDC1000 to start using the HDC1080, but the distributor is telling us they can't accept them in trade unless it is the date code is the 1527 or earlier. So right now we have customers back orders we can't fill because the sensor is still reading incorrectly and we can't even trade the unused sensors in. We need to get this fixed ASAP. 

  • 0 in reply to Jeremy Corkran
    TI__Expert 5145 points
    Hi Jeremy,
    Sorry for the delay in the answer.
    Please try to contact me to my email address so that we can try to solve your problem.
    Best regards,
    Carmine