11.1.6 Footprint Recommendations
- Stencil parameters for the EP (Exposed Pad) such as aperture area ratio and the fabrication process have a significant impact on paste deposition. TI highly recommends inspecting the stencil before setting the placement of the WQFN package to improve board assembly yields. If the via and aperture openings are not carefully monitored, the solder may flow unevenly through the EP. Stencil parameters for aperture opening and via locations are shown in the RTV package drawing in Mechanical, Packaging, and Orderable Information.
- The EP of the package must be connected to the ground plane through a 3 × 3 via array. These vias are solder-masked to avoid solder flowing into the plated-through holes during the board manufacturing process. Details about via dimensions are also shown in the RTV package drawing in Mechanical, Packaging, and Orderable Information.
More information on the WQFN style package is provided in QFN/SON PCB Attachment Application Report (SLUA271).