Quectel SC200L-EM Hardware Design page 83

Push the squeegee to apply the solder paste on the surface of stencil, thus making the paste fill the
stencil openings and then penetrate to the PCB. The force on the squeegee should be adjusted properly
so as to produce a clean stencil surface on a single pass. To ensure the module soldering quality, the
thickness of stencil for the module is recommended to be 0.18 mm~0.20 mm. It is recommended to
slightly reduce the amount of solder paste for LGA pads, thus avoiding short-circuit. For more details,
please refer to document [5].
It is suggested that the peak reflow temperature is 238~246 ºC, and the absolute maximum reflow
temperature is 246 ºC. To avoid damage to the module caused by repeated heating, it is strongly
recommended that the module should be mounted after reflow soldering for the other side of PCB has
been completed. The recommended reflow soldering thermal profile (lead-free reflow soldering) and
related parameters are shown below:
Temp. (°C)
246
238
220
200
Soak Zone
150
100
Figure 39: Recommended Reflow Soldering Thermal Profile
Table 12: Recommended Thermal Profile Parameters
Factor
Soak Zone
Max slope
Soak time (between A and B: 150 °C and 200 °C)
Reflow Zone
SC200L_Hardware_Design
A
Max slope: 1~3 °C/s
SC200L Hardware Design
Reflow Zone
Max slope:
2~3 °C/s
B
Recommendation
1 to 3 °C/sec
70 to 120 sec
Cooling down slope:
C
-1.5 ~ -3 °C/s
D
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