SNLS477B October 2014 – November 2018 DS90UB948-Q1
Stencil parameters such as aperture area ratio and the fabrication process have a significant impact on paste deposition. Inspection of the stencil prior to placement of the WQFN package is highly recommended to improve board assembly yields. If the via and aperture openings are not carefully monitored, the solder may flow unevenly through the DAP. Stencil parameters for aperture opening and via locations are shown in Figure 55:
|DEVICE||PIN COUNT||MKT DWG||PCB I/O Pad SIZE (mm)||PCB PITCH (mm)||PCB DAP SIZE(mm)||STENCIL I/O APERTURE (mm)||STENCIL DAP APERTURE (mm)||NUMBER OF DAP APERTURE OPENINGS||GAP BETWEEN DAP APERTURE (Dim A mm)|
|DS90UB948-Q1||64||NKD||0.25 × 0.6||0.5||7.2 x 7.2||0.25 x 0.6||1.16 × 1.16||25||0.2|
Figure 56 (PCB layout example) is derived from a layout design of the DS90UB948-Q1. This graphic and additional layout description are used to demonstrate both proper routing and proper solder techniques when designing in the Deserializer.