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09/16 Rev 1

Application Notes

5.

Humidity Control Of PCB-Mounted Parts

If the moisture-sensitive SMD parts will not undergo further reflow or other high-temperature processes, then no

special treatment is required. However, if the PCB assembly requires further reflow or other high-temperature

process, including rework, then the mounted SMD’s exposure time should continue to accumulate against the MSL

limit, unless the board is kept in a dry environment (<5% RH).If the exposure time exceeds the MSL limit, the

board and part must be baked dry to reset the exposure time before undergoing further reflow.

If the part’s silicone lens extends beyond the board’s edge after installation, proper protection Should be made

(such as covers) to prevent accidental impact or stress on the exposed lens that would cause damage or detachment.

The silicone lens may withstand up to 1.5-newton in shear force when properly mounted.If external protection is not

available, strongly suggest following these handling procedures to prevent damage:

1. When the PCB assembly is handled or transported after reflow soldering, care must be taken to prevent accidental

contact or impact on the exposed silicone lens.

2. When the PCB assembly is installed into the casing or panel, care must be taken to maintain sufficient clearance

for the lens.

3. Do not subject the silicone lens to outside impact or friction.

1. Do not use unknown chemicals or acidic solvents to clean the part. Please check to insure the cleaning solvent

will notcorode epoxy resin,silicone resin, silver plating, and other component materials before using.

2. VCC suggests ethanol as a safe solvent for use with the surface mount devices. Softly wipe away any surface

partcles,avoiding excessive force scratching the surface or damaging the structures. Then place down and allow to

naturally dry under room temperature conditions before further use. Do not soak the component in the solvent.

Installation and Usage

Cleaning

Compliances and Approvals