SNLS244H September 2006 – January 2016 DS42MB100
Use at least a four layer board with a power and ground plane. Closely-coupled differential lines of 100 Ω are typically recommended for differential interconnect. The closely coupled lines help to ensure that coupled noise will appear as common-mode and thus will be rejected by the receivers. Information on the WQFN style package is provided in AN-1187 Leadless Leadframe Package (LLP), SNOA401.
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 19. A layout example for the DS42MB100 is shown in Figure 20, where 16 stencil openings are used for the DAP alongside nine vias to GND.
|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)|
|DS42MB100||36||SQA36A||0.25 × 0.6||0.5||4.6 × 4.6||0.25 × 0.7||1.0 × 1.0||16||0.2|