Si1000/1/2/3/4/5
Table 3.3. PCB Land Pattern
Dimension
Value
C1
4.75
X1 (27x)
Y1 (27x)
C2
0.95
0.30
7.00
0.30
0.70
0.50
>1.00
0.125
2.73
2.63
1.59
3.16
2.97
0.07
1.42
X2 (15x)
Y2 (15x)
E
K
X3
X4
Y4
Y5
X6
Y6
X7
Y7
General
1. All dimensions shown are in millimeters (mm) unless otherwise noted.
2. This land pattern design is based on the IPC-7351 guidelines.
PCB Design
1. High-Tg PCB materials (Glass Transition Temperature > 170° C are recommended for Pb-free reflow profiles per standard industry practice.
2. PCB design must ensure sufficient thermal relief for operation of the device.
3. Via placement must minimize mechanical stress due to CTE mismatch between PCB material and the package while maintaining electrical or
thermal performance as required for the particular application.
a. A minimum of four vias are required under each E-pad; eight or more vias are recommended for designs that require increased thermal
conductivity.
b. Via diameters should be between 0.20 and 0.31 mm (8 to 12 mil).
c. Metal-to-metal distance between outer edge of via diameter and closest edge of device perimeter pad must be > 1.00 mm (dimension "K").
d. Vias may be placed as desired within the non-hatched area of the E-pads. Final via size and quantity is dependent on choice of PCB
materials and total thermal relief provided by internal Cu plane in the PCB.
e. Vias should either be filled or tented on the top-side of the board to prevent solder from migrating away from the E-pads during reflow.
Solder Mask Design
1. All metal pads are to be non-solder mask defined (NSMD). Clearance between the solder mask and the metal pad should be 60 µm minimum
around the pad.
Stencil Design
1. A stainless steel, laser-cut and electro-polished stencil with trapezoidal walls should be used to assure good solder paste release.
2. The stencil thickness should be 0.125 mm (5 mils).
3. The ratio of stencil aperture to land pad size should be 1:1 for all perimeter pads.
4. A 3x3 array of 0.7 mm square openings on 0.9 mm pitch should be used for the upper center ground pad.
5. A 3x3 array of 0.8 mm square openings on 1.0 mm pitch should be used for the lower center ground pad.
Card Assembly
1. A No-Clean, Type-3 solder paste is recommended.
2. The recommended card reflow profile is per the JEDEC/IPC J-STD-020 specification for Small Body Components.
Rev. 1.0
39
SILICON [ SILICON ]
