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HDC1080: On the temperature offset of the HDC1080

Noriaki Fukazawa
Expert 1620 points
Part Number: HDC1080

Dear Expert

I have a question about HDC1080.

In the HDC 1080 used by my customers,
Variations in output accuracy are confirmed.

There are two kinds of boards on which the HDC 1080 is mounted.
'' Substrate with problem in accuracy '' '' Substrate prepared for replacement ''

Even though the two boards are designed and manufactured with exactly the same pattern, outline and measurement conditions
There is an error in humidity detection accuracy regardless of it.

Think of factors of temperature offset from past threads,
Layout etc. are exactly the same, other factors are considered.
E2E: http: //e2e.ti.com/support/sensor/humidity/f/985/t/517761

Below is a table of measured values ​​attached, but calibration
Attached is the data of the ideal value and measured value that I went through.

Despite the fact that the accuracy of temperature is almost flat, only the accuracy of humidity,
There is a big error in the plus direction.

I am staring that there is an error in humidity due to factors other than Temperature Offset,
Please tell us your views.

Best,Regars

FukazawaHDC1080 Measurement result.xlsx

  • 0
    TI__Expert 5695 points
    HI Fukazawa-san,
    Based on the data you shared with us we can understand that the temp sensor is working just fine, however the humidity sensor has a offset between 5 & 6%. I assume your i"deal" values are coming from a Humidity chamber? Can you please share more details on the setup?

    There are different reasons to have such an offset other than a temperature one.

    1) Contamination on the humidity Sensor due to improper handling or soldering.
    2) Exposing the part to non recommended conditions for operation. e.g. high temps for significant times.

    Please refer to the following app notes where the details are explained.

    Optimizing Placement and Routing for Humidity Sensors (Rev. A) www.ti.com/.../snaa297
    Humidity Sensor: Storage and Handling Guidelines: www.ti.com/.../snia025
  • 0 in reply to Jose Arteaga4
    Expert 1620 points
    Hello Jose-san,

    Thank you for your reply!!
    I want to solve the cause of humidity error in HDC1080.
    I will share the HDC 1080 setup information.
    What is necessary setup information?

    Thank you for introducing the application note.
    I will check again.

    Bets,Regars
    Fukazawa
  • 0 in reply to Noriaki Fukazawa
    TI__Expert 5695 points
    Hi Fukazawa-san,
    The details we need on the test setup are: (1) Is this controlled environment (e.g. chamber) (2) Temperatures forced in the device and duration of these. (3) Since sensor contamination may affect the humidity accuracy pls double check that all guidelines in the application notes are followed.

    Regards,
    Jose
  • 0 in reply to Jose Arteaga4
    Expert 1620 points
    Hello Jose-san,

    I am sorry that the reply was delayed.
    Last time I introduced you two application notes to me,
    I told my customer to check it.
    However, humidity errors were not resolved.

    Unfortunately, my customers are considering changing parts from HDC 1080.
    When baking the HDC 1080,
    What is the temperature that this IC can handle?

    Is 120 ° C OK?
    Is 80 ° C OK?
    Is 60 ℃ OK?

    Best, Regars
    Fukazawa
  • 0 in reply to Noriaki Fukazawa
    TI__Expert 5695 points
    The temperature sensor is specified from -40C to 125C
    The humidity sensor is specified from -20C to 70C (page 4 on data sheet)

    Please note the following footnote on page 5 of the data sheet, this is very important:
    (11) Recommended humidity operating range is 10% to 70% RH. Prolonged operation outside this range may result in a measurement
    offset. The measurement offset will decrease after operating the sensor in this recommended operating range.

    Regards,
    Jose
  • 0 in reply to Jose Arteaga4
    Expert 1620 points
    Hello Jose-san,

    Thank you for your special support.
    Please tell me about handling HDC1080.

    <Question>
    Is this product adversely affected by bringing the organic solvent close to it?
    For example, a tape may be stuck on the surface of a part,
    If you leave the board wrapped in red or blue bubble wrap (cushioning material) and leave it for days
    Is it possible that the error of the measurement result becomes large?

    Currently, customers are asked to investigate the cause of humidity detection error.

    Best,Regars.
    Fukazawa
  • 0 in reply to Noriaki Fukazawa
    Expert 1620 points
    Hello Jose-san,

    If you haven’t already, please take a moment to read the following message.
    If you have, thank you.

    <Question>
    Is this product adversely affected by bringing the organic solvent close to it?
    For example, a tape may be stuck on the surface of a part,
    If you leave the board wrapped in red or blue bubble wrap (cushioning material) and leave it for days
    Is it possible that the error of the measurement result becomes large?

    Best,Regars.
    Fukazawa
  • 0 in reply to Noriaki Fukazawa
    TI__Expert 5695 points
    Fuzakawa-san,

    The humidity sensor may be affected adversely with chemicals such as solvents.
    Section One of one of the application notes I shared with you clearly states that:
    "Exposure to Contaminants
    Humidity sensors are not standard ICs and therefore must not be exposed to particles or volatile chemicals such as solvents or other organic compounds"

    Now how close is too close? it's a matter of checking on the user side, TI can't guess all possible scenarios. TI don't support protective tapes in any of the humidity sensors now.

    The scenario you describe could affect (e.g. contaminate) the sensor or not, depending how clean the interior side of the bag is.
    Again, the handling and storage application note should be read carefully.

    Humidity Sensor: Storage and Handling Guidelines: www.ti.com/.../snia025\

    If you have further questions, please open a new e2e thread since you typically take few weeks to update your questions and it's harder to tack older posts.

    Regards,
    Jose