LITEON. as one might suspect, is primarily a purveyor of optoelctronics components and accessories, including their LTST-C150TBKT. We’ve had a few questions recently concerning this device’s MSL listing and why it occasionally shows up marked as something other than MSL 3. What’s the deal?
As is the case with many other products with similar discrepancies, the MSL rating for this product is not necessarily set solely by the supplier. The final assembler also has a say, with some assembly facilities producing tighter, more moisture-resistant packages than others. MSL 3 is a baseline for the product series, but if your individual products are marked with something different, trust the marking on the received product.
In addition, supplier documentation has the following to say concerning storage and handling for these products.
The storage ambient for the LEDs should not exceed 30°C temperature or 70% relative humidity. It is recommended that LEDs out of their original packaging are IR-reflowed within one week. For extended storage out of their original packaging, it is recommended that the LEDs be stored in a sealed container with appropriate desiccant, or in a desiccators with nitrogen ambient.LEDs stored out of their original packaging for more than a week should be baked at about 60 deg C for at least 24 hours before solder assembly.