C8051F970-A-GM Datasheet, PDF (48/454 Pages) Silicon Laboratories – Low Power Capacitive Sensing MCU with up to 32 kB of Flash

C8051F97x
Table 6.2. QFN-32 PCB Land Pattern
Dimension
MIN
C1
4.80
MAX
4.90
C2
4.80
4.90
E
0.50 BSC
X1
0.20
0.30
X2
3.20
3.40
Y1
0.75
0.85
Y2
3.20
3.40
Notes:
General
1. All dimensions shown are in millimeters (mm) unless otherwise noted.
2. This Land Pattern Design is based on the IPC-7351 guidelines.
Solder Mask Design
3. 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
4. A stainless steel, laser-cut and electro-polished stencil with trapezoidal walls should
be used to assure good solder paste release.
5. The stencil thickness should be 0.125mm (5 mils).
6. The ratio of stencil aperture to land pad size should be 1:1 for all perimeter pads.
7. A 3 x 3 array of 1.0 mm square openings on 1.2 mm pitch should be used for the
center ground pad.
Card Assembly
8. A No-Clean, Type-3 solder paste is recommended.
9. The recommended card reflow profile is per the JEDEC/IPC J-STD-020 specification
for Small Body Components.
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Rev 1.0