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HDC3022: How do I achieve IP67?

Jason Harrington
Prodigy 50 points
Part Number: HDC3022

Tool/software:

I see that the HDC301 is the recommended sensor when applying conformal coating, due to the use of Kapton tape. But what if you want to design a board with an IP67 rating using the HDC3022? Is there a reference design? Wouldn't some form of conformal coating be necessary to achieve that level of ingress protection? Is it possible to mask the PTFE filter, considering it's porous? I would imagine that could be difficult. Alternatively, is there a preferred conformal coating with low or no VOC content that's recommended for this application?

  • +1
    TI__Expert 3355 points

    Hi Jason,

    Humidity sensors have an open cavity on the top, because the sensing element must be exposed to ambient air in order to measure humidity. The HDC3022 has an IP67-rated PTFE filter over the sensing cavity. If you also need to waterproof the entire board with a conformal coating, you must ensure the coating is not applied on top of the sensor. 

    Our recommendation would be to temporarily apply Kapton tape (or another polyimide tape) on top of the sensor to protect the cavity during conformal coating, then after the coating is cured you can remove the tape. Unfortunately this would be a manual process.

    We don't have a specific conformal coating to recommend, however you may refer to the HDC3x Silicon Users Guide section 2 for a non-exhaustive list of known problematic chemicals. 

    Best,

    Sakeenah