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HDC2010: Flux spatter

Part Number: HDC2010
Other Parts Discussed in Thread: HDC2080, HDC1080

Hi Team,

My customer is interested in HDC and I got a question about Flux Spatter caused by void(air bubble).

HDC2010 datasheet mentions below and customer follows below statement but even if they use no-clean solder paste, flux spatter might happen because void is in no-clean solder paste.
"When soldering the HDC2010, it is mandatory to use no-clean solder paste, and the paste must not be exposed to water or solvent rinses during assembly because these contaminants may affect sensor accuracy.".

Do we have a risk that flux spatter adheres to RH sensor?
If yes, do you have any test data what flux spatter causes to the sensing accuracy?


  • Dear Kai - 

    Flux spatter is most likely not caused by air bubble, but more from the change in state of the flux as it is blended with the solder and evaporated, right at the melting point of the solder. There is a company in Adachi-ku (right near the Arakawa river) called Koki, who makes a solder which is promoted to be low-spatter, if that is a concern for the customer. They can reach out to them to discuss perhaps. 

    Regarding the sensor - the main reason we have strong recommendation to use no clean solder is to avoid the water wash, which over-hydrates the parts about 10-15%, from what I have seen with customer implementations as a secondary reason to avoid leaving particles on the sensor element itself, which degrades the performance of the part, but is not quantifiable, as each case or instance would be different. With the HDC2010, however, we really don't see any solder splash or flux spatter issues with it, as it is upside down as compared to the top surface open cavity device like the HDC1080 or HDC2080 or the competitive devices like those. Most of the issues we see with that device are related to either customer washing the board or exposing to other chemicals which degrade the device.