IR3628MPbF

08/10/2007

Stencil Design

The stencil apertures for the lead lands should be approximately 80% of the area of the lead lands.

Reducing the amount of solder deposited will minimize the occurrence of lead shorts. Since for 0.5mm

pitch devices the leads are only 0.25mm wide, the stencil apertures should not be made narrower;

openings in stencils < 0.25mm wide are difficult to maintain repeatable solder release.

The stencil lead land apertures should therefore be shortened in length by 80% and centered on the

lead land.

The land pad aperture should deposit approximately 50% area of solder on the center pad. If too

much solder is deposited on the center pad the part will float and the lead lands will be open.

The maximum length and width of the land pad stencil aperture should be equal to the solder resist

opening minus an annular 0.2mm pull back to decrease the incidence of shorting the center land to the

lead lands when the part is pushed into the solder paste.

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