light sensitive of nRF52832 WLCSP package

[bigocean]

Hi, all

      Recently I use nRF52832 CIAA, WLCSP package to develop a project。From nRF52832 Product Specification，it writes below：      

      “All WLCSP package variants are sensitive to visible and close-range infrared light. This means that a final product design must shield the chip properly, either by final product encapsulation or by shielding/coating of the WLCSP device.”

      Is there any information about light sensitive spec of nRF52832 WLCSP package。

      What we concerns is:   

       Which fuction and performance of nRF52832 WLCSP will be affected by visible and close-range infrared light?  What measure should we take to avoid or alleviate the affect in our production process？

Best regards,

bigocean

[ketiljo]

Visible light has no impact. IR light can have impact on the analog modules if the light is powerful enough. The silicon is opaque to IR light and the photons in the light will affect the transistors. Just like a photo diode or transistor where this effect is used by purpose. 

If he device is inside an housing, it's usually more than enough to block the IR light. If the housing doesn't filter the IR light, the device can be covered with IR blocking epoxy.

[franck]

Hello, I'm interested by third party module (fanstell/raytac) that are shielded but as shielding are not full closed worried of any problem with it.

I am wondering as IR signal can go through these kind of holes, as my enclosure is transparent and device receive infrared pulse code to infrared receiver installed on same board. 

I don't use any analog device does this mean I will not have any problem. Or some analog part is used for RF or anything 

Exemple below is not WLCSP but just here for explaining small holes on shield

Thanks Franck

 

[ketiljo]

Unless you direct the IR light directly into the hole, it shouldn't be a problem. The only effect you are likely to see, is increased current draw when it's exposed to strong IR light.