Data Sheet

Thundercomm TurboX C40x SOM Datasheet
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1.5. Stencil design and aperture
To supply sufficient soldering paste and keep reliable soldering joints, add the thickness of stencil partly on the top
surface. The stencil aperture for single sheet cannot be greater than 3.0mm×4.0mm and the exceeded part should
be divided into smaller apertures with applicable shelves. A clearance of over 2.0mm should be kept between the
outward end of the aperture and the component if there are components around the module.
 NOTE:
 For the convenience of heating and repairing, it is recommended that no components should be placed in the
area at the backside of the module on PCB.
 In order to avoid reverse polarity of the module, it is recommended to use asymmetric pads at the bottom of the
module to identify the module polarity during module placement.
 It is not recommended to add any silkscreen in the area where the module is mounted to avoid the height that
may influence the solder paste printing and soldering quality.
 When there is a need to step-up the stencil, all 01005/0201, 0.4mm-pitch and 0.5mm-pitch components should
be kept over 5.0mm away from the stepped-up area to avoid solder bridging that is caused by thicker solder paste.
Figure 1-6. Stencil Aperture
 Stencil thickness
Area of the module should be partly stepped-up to 0.15mm-0.18mm.
 Pads on four sides
The aperture for each single pad should be centered with area reduced to 75%-85%. And the shape should be
rectangle with round chamfers (see Figure 1-6).
 Pads at four corners
The stencil aperture should be designed with 60%~65% area of the corresponding pad (see Figure 1-6).
nicholas.wang_thundercomm.com
2022-07-21 2:34:47 AM CST