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HDC3022 mechanical integration

Antti Immonen
Prodigy 10 points
Part Number: HDC3022

Hey there,

We're looking to integrate a HDC3022 in our device with the filter membrane being pressed against an opening as shown in the attached illustration. We did not find a reference of this method in any related design guidelines, closest app report we found is snaa297. 

Questions:

Is this method something that would work and how much membrane compression is allowed/recommended here?

Could this applied compression significantly hinder water vapor passage?

Thanks,

Antti

  • 0
    TI__Genius 10070 points

    Hi Antti,

    Thank you for posting to the Sensing forum.

    The HDC3022 datasheet values are specified with regards to the permanent IP67 filter. The sensor input will be altered from calibrated values if there is a second filter or membrane added to the end application. 

    Additionally, the precision references used in temperature sensors have been known to shift slightly as a result of mechanical stresses. However, we have not performed this testing on the HDC302x. If the applied compression is constant, any detected output changes may be accounted for using the programmable offset values.

    Best regards,

    Nicole

  • 0 in reply to Nicole Khoury
    Prodigy 10 points

    Hey Nicole,

    And thanks for your reply. I am sorry for any confusion, it seems you misunderstood my question. We are not using a second membrane, instead, we're placing the sensor's membrane side against an opening in an enclosure (a round hole). And when we press the sensor against this area with the hole, we subject the membrane to a moderate compression. Does the cross-sectional view of my original question now make more sense to you?

    I am not talking about compressive forces that could affect things inside of the molded HDC3022 package, rather, my question is about whether the membrane would work as inteded in this kind of a mechanical configuration.

    Thanks again,

    Antti

  • 0 in reply to Antti Immonen
    TI__Genius 10070 points

    Hi Antti,

    I apologize for the misunderstanding.

    I would not expect there to be an issue caused by the compression. However, the values specified in the datasheet are for an unobstructed sensor opening + IP67 filter. If there are parts of the enclosure blocking the filter this may affect the input seen by the sensor.

    Best regards,
    Nicole

  • 0 in reply to Nicole Khoury
    Prodigy 10 points

    Nicole,

    This is good to know. We are still exploring options for the sensor integration. Could you share any further specifications about the membrane that is included with the HDC3022, and whether this specific membrane material or equivalent is something that is commercially available for purchase separately?

    Thanks again,

    Antti

  • 0 in reply to Antti Immonen
    TI__Guru* 91206 points

    Dear Antti - 

    This kind of material (PTFE membrane) can be obtained from a supplier like Porex, who can work with you to accommodate your housing/mechanical needs.

    https://www.porex.com/porous-polymers-technology/ptfe-hydrophobic-membrane/