Silicon Laboratories C8051F347 - Manual (Page 36)

C8051F340/1/2/3/4/5/6/7/8/9/A/B/C/D
36 Rev. 1.3
Figure 4.6. LQFP-32 Recommended PCB Land Pattern
Table 4.5. LQFP-32 PCB Land Pattern Dimensions
Dimension Min Max
C1 8.40 8.50
C2 8.40 8.50
E 0.80 BSC
X1 0.40 0.50
Y1 1.25 1.35
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 µm 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 0.125 mm (5 mils).
6. The ratio of stencil aperture to land pad size should be 1:1 for all pads.
Card Assembly:
7. A No-Clean, Type-3 solder paste is recommended.
8. The recommended card reflow profile is per the JEDEC/IPC J-STD-020
specification for Small Body Components.