Installation Instructions

LISA-U2 series - System Integration Manual
UBX-13001118 - R19 Early Production Information Handling and soldering
Page 154 of 175
Preheat phase
Initial heating of component leads and balls. Residual humidity will be dried out. This preheat phase will not
replace prior baking procedures.
 Temperature rise rate: max 3°C/s If the temperature rise is too rapid in the preheat phase it may cause
excessive slumping.
 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 74: Recommended soldering profile
LISA-U2 modules must not be soldered with a damp heat process.
When soldering lead-free LISA-U2 series modules in a leaded process, check the following temperatures: