User's Manual

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71
HW Design Guidelines
Total Time/217°C
90.55
85.88
90.09
76.90
13.65
22%
4%
20%
–32%
Gradient1 (100–150°C)
1.91
1.83
1.93
1.78
0.15
27%
22%
29%
19%
Process limit:
Solder Paste
Lead-free
Profile feature
Min.
Max.
Unit
Gradient1 (Target = 1.5) (100 °C–150 °C)
(Time period = 20 s)
0
3
°C/S
Preheat time from 140 °C to 190 °C
70
105
S
Time maintained above 230 °C
40
60
S
Peak package body temperature
230
250
°C
Time maintained above 217 °C
60
110
S
6.3. PCB pad design
Non solder mask defined (NSMD) type is recommended for the solder pads of the PCB on
which M18QF/M18QA Series modules will be mounted, this kind of design is good to
soldering reliability in SMT process.
Figure 22. NSMD solder pad design