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OPA189: REDUCING HUMIDITY EFFECT

Thomas Targosz
Prodigy 30 points
Part Number: OPA189


This application is high gain.  Humidity is a concern can you recommend a coating which can reduce the affect the humidity has on the signal.

  • 0
    TI__Guru* 93105 points
    Hello Thomas,

    We do not evaluate our precision amplifiers such as the OPA189 with a conformal coating. A search on the internet indicates there are various coating formulations, and we don't know what effects the different ones might have on the OPA189 electrical performances. Therefore, it is best we don't make a recommendation.

    Regards, Thomas
    Precision Amplifiers Applications Engineering
  • 0
    Guru 140200 points
    Hi Thomas,

    we are using potting material being recommended for electronic applications. Two-component polyurethane casting compounds are well suited, provided they have a low shore hardness. Perfect cleaning of the PCB before potting is extremely important. And guarantee that the two components are perfectly mixed!

    Kai
  • 0 in reply to Thomas Kuehl
    TI__Guru* 93105 points
    Hi Thomas,

    Kai is speaking from experience so that is surely better advice than I can provide. His point about cleanliness can't be emphasized enough. Any residual solder flux, or other contaminant remaining on the board, or under the OPA189 can degrade the dc electrical performance; especially, bias currents. And it certainly has implications regarding the adhesion of a conformal coating.

    Regards, Thomas
    Precision Amplifiers Applications Engineering
  • 0 in reply to Thomas Kuehl
    TI__Genius 11135 points
    Thomas

    We haven't heard back from you so we assume this answered you question. If you need more help just post another reply below.

    Thanks
    Dennis