Integration Manual

SARA-R4/N4 series - System Integration Manual
UBX-16029218 - R11 Handling and soldering Page 123 of 157
 Time: 60 – 120 s If the preheat is insufficient, rather large solder balls tend to be
generated. Conversely, if performed excessively, fine balls and
large balls will be generated in clusters.
 End Temperature: +150 - +200 °C If the temperature is too low, non-melting tends to be caused
in areas containing large heat capacity.
Heating/ reflow phase
The temperature rises above the liquidus temperature of +217 °C. Avoid a sudden rise in temperature as
the slump of the paste could become worse.
 Limit time above +217 °C liquidus temperature: 40 - 60 s
 Peak reflow temperature: +245 °C
Cooling phase
A controlled cooling avoids negative metallurgical effects (solder becomes more brittle) of the solder and
possible mechanical tensions in the products. Controlled cooling helps to achieve bright solder fillets with
a good shape and low contact angle.
 Temperature fall rate: max 4 °C/s
☞ To avoid falling off, modules should be placed on the topside of the motherboard during soldering.
The soldering temperature profile chosen at the factory depends on additional external factors like choice
of soldering paste, size, thickness and properties of the base board, etc.
⚠ Exceeding the maximum soldering temperature and the maximum liquidus time limit in the
recommended soldering profile may permanently damage the module.
Preheat Heating Cooling
[°C] Peak Temp. 245°C [°C]
250 250
Liquidus Temperature
217 217
200 200
40 - 60 s
End Temp.
max 4°C/s
150 - 200°C
150 150
max 3°C/s
60 - 120 s
100 Typical Leadfree 100
Soldering Profile
50 50
Elapsed time [s]
Figure 56: Recommended soldering profile