C8051F960-B-GM Datasheet, PDF (51/492 Pages) Silicon Laboratories – Ultra Low Power 128K, LCD MCU Family

C8051F96x
Figure 3.8. QFN-40 Landing Diagram
Table 3.6. QFN-40 Landing Diagram Dimensions
Dimension
Min
Max
Dimension
Min
Max
C1
5.80
5.90
C2
5.80
5.90
e
0.50 BSC
X1
0.15
0.25
X2
4.10
4.20
Y1
0.75
0.85
Y2
4.10
4.20
Notes:
General
1. All dimensions shown are in millimeters (mm) unless otherwise noted.
2. Dimension and Tolerancing is per the ANSI Y14.5M-1994 specification.
3. This Land Pattern Design is based on the IPC-SM-7351 guidelines.
4. All dimensions shown are at Maximum Material Condition (MMC). Least Material Condition (LMC) is
calculated based on a Fabrication Allowance of 0.05 mm.
Solder Mask Design
5. All metal pads are to be non-solder mask defined (NSMD). Clearance between the solder mask and
the metal pad is to be 60 m minimum, all the way around the pad.
Stencil Design
6. A stainless steel, laser-cut and electro-polished stencil with trapezoidal walls should be used to
assure good solder paste release.
7. The stencil thickness should be 0.125 mm (5 mils).
8. The ratio of stencil aperture to land pad size should be 1:1 for all perimeter pads.
9. A 4x4 array of 0.80 mm square openings on a 1.05 mm pitch should be used for the center ground
pad.
Card Assembly
10. A No-Clean, Type-3 solder paste is recommended.
11. Recommended card reflow profile is per the JEDEC/IPC J-STD-020 specification for Small Body
Components.
Rev. 1.0
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