Silicon Labs

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8 Soldering Recommendations

BLE121LR is compatible with industrial standard reflow profile for Pb-free solders. The reflow profile used is

dependent on the thermal mass of the entire populated PCB, heat transfer efficiency of the oven and

particular type of solder paste used. Consult the datasheet of particular solder paste for profile configurations.

Silicon Laboratories will give following recommendations for soldering the module to ensure reliable solder

joint and operation of the module after soldering. Since the profile used is process and layout dependent, the

optimum profile should be studied case by case. Thus following recommendation should be taken as a

starting point guide.

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Refer to technical documentations of particular solder paste for profile configurations

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Avoid using more than one flow.

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Reliability of the solder joint and self-alignment of the component are dependent on the solder volume.

Minimum of 100

m stencil thickness is recommended.

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Aperture size of the stencil should be 1:1 with the pad size.

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A low residue, “no clean” solder paste should be used due to low mounted height of the component.

Figure 26: Reference reflow profile