Figure 8: SOM240 Connector Pad and Standoff Placement
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Board to Board Connector Stencil Design
To ensure that at time zero no crack has occurred, solder paste is applied to PCB metal pads
using screen printing. The volume of the printed solder paste is determined by the stencil
aperture and its thickness. In most cases, the thickness of a stencil must be matched to the needs
of all components on the PCB. Stencil apertures should be a circular shape. A laser cutting
(mostly made from stainless steel) with nickel blanking is preferred to ensure that both uniform
and high-solder paste is transferred to the PCB. The recommended stencil design dimensions are
listed in the following table and shown in the image.
Chapter 3: Mechanical Design Considerations
UG1091 (v1.0) April 20, 2021
Carrier Card Design for Kria SOM
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