GE Industrial Solutions NaOS NXA025 SMT - Manual (Page 19)

Data Sheet
October 5, 2009 Naos TM NXA025 SMT Non-isolated Power Modules:
10 – 14Vdc Input; 0.8Vdc to 5.5Vdc Output; 25A output current
LINEAGE POWER 19
Surface Mount Information (continued)
Reflow Soldering Information
These NXA025series power modules are large mass,
low thermal resistance devices and typically heat up
slower than other SMT components. It is
recommended that the customer review data sheets
in order to customize the solder reflow profile for each
application board assembly.
The following instructions must be observed when
SMT soldering these units. Failure to observe these
instructions may result in the failure of or cause
damage to the modules, and can adversely affect
long-term reliability.
These surface mountable modules use our newest
SMT technology called “Column Pin” (CP) connectors.
Fig 32 shows the new CP connector before and after
reflow soldering onto the end-board assembly.
NXA Board
Insulator
Solder Ball
End assembly PCB
Figure 32. Column Pin Connector Before and After
Reflow Soldering.
The CP is constructed from a solid copper pin with an
integral solder ball attached, which is composed of
tin/lead (Sn/Pb) solder. The CP connector design is
able to compensate for large amounts of co-planarity
and still ensure a reliable SMT solder joint.
Typically, the eutectic solder melts at 183 o C, wets the
land, and subsequently wicks the device connection.
Sufficient time must be allowed to fuse the plating on
the connection to ensure a reliable solder joint. There
are several types of SMT reflow technologies
currently used in the industry. These surface mount
power modules can be reliably soldered using natural
forced convection, IR (radiant infrared), or a
combination of convection/IR. For reliable soldering
the solder reflow profile should be established by
accurately measuring the modules CP connector
temperatures.
R
E
FL
O
W
TE
M
P
(°
C)
0
50
100
150
200
250
300
Preheat zo ne
max 4
o Cs -1
Soak zo ne
30-240s
Heat zone
max 4
o Cs -1
Peak Temp 235 o C
Co oling
zone
1-4
o Cs -1
T
lim
above
205 o C
REFLOW TIME (S)
Figure 32. Recommended Reflow Profile.
MAX
TE
MP S
O
LD
ER
(°
C)
200
205
210
215
220
225
230
235
240
0 10 20 30 40 50 60
TIME LIMIT (S)
Figure 33. Time Limit Curve Above 205 o C Reflow.