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LM3691 light sensitivity

Other Parts Discussed in Thread: LM3691, LM3671

I suppose this applies to any chip in the DSBGA package, but I'm wondering how the LM3691 behaves when exposed to light. From the part's datasheet:

The DSBGA package is optimized for the smallest possible size in applications with red or infrared opaque cases. Because the DSBGA package lacks the plastic encapsulation characteristic of larger devices, it is vulnerable to light. Backside metallization and/or epoxy coating, along with front side shading by the printed circuit board, reduce this sensitivity. However, the package has exposed die edges. In particular, DSBGA devices are sensitive to light, in the red and infrared range, shining on the package’s exposed die edges.

Specifically, I'd like to use it, or something similar, to get 3.3V from USB on a board that is exposed to ambient light. If doing so would be unwise without some sort of case/coating, I would welcome alternate part suggestions. Otherwise, what happens to the part and its performance?

Relevant datasheet and DSBGA application note.

  • Hi,

    this disclaimer apply to all DSBGA package part, normally you should see any problem with ambient light, however, you need to pick a LLP or SOT package if you want to play safe.. LM3671 provides all three packages I believe..