u-blox NORA-W2 Series, Hardware Integration Manual

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NORA-W2 series - Hardware integration manual
UBX-22005177 - R01 Handling and soldering Page 33 of 61
C1 – Public
5.3 Reflow soldering process
NORA-W2 series modules are surface mount modules supplied on a FR4-type PCB with gold plated
connection pads and are produced in a lead-free process with a lead-free soldering paste. The
thickness of solder resist between the host PCB top side and the bottom side of the NORA-W2 series
module must be considered for the soldering process.
The module is compatible with industrial reflow profile for RoHS solders. Use of "No Clean" soldering
paste is strongly recommended.
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. The optimal soldering profile must be
trimmed for each case depending on the specific process and PCB layout.
⚠
The target values given in Table 8 and Figure 13 are given as general guidelines for a Pb-free
process only. For further information, see also the JEDEC J-STD-020E standard [8] .
Process parameter Unit Value
Pre-heat Ramp up rate to T
SMIN
K/s 3
T
SMIN
°C 150
T
SMAX
°C 200
t
S
(from +25 °C) s 150
t
S
(Pre-heat) s 60 to 120
Peak T
L
°C 217
t
L
(time above T
L
) s 40 to 60
T
P
(absolute max) °C 245
Cooling Ramp-down from T
L
K/s 4
Allowed soldering cycles - 2
Table 8 : Recommended reflow profile
Figure 13: Reflow profile
Lower value of T
P
and slower ramp down rate (2 – 3 °C/sec) is preferred.