GE Industrial Solutions KSTW004A2B Barracuda Series - Manual (Page 10)

GE Data Sheet
KSTW004A2B Barracuda™ Series; DC-DC Converter Power Modules
36-75Vdc Input; 12.0Vdc, 4.2A, 50W Output
April 1, 2013 ©2012 General Electric Company. All rights reserved. Page 10
Surface Mount Information
Pick and Place
The KSTW-SR series of DC-to-DC power converters use an
open-frame construction and are designed for surface mount
assembly within a fully automated manufacturing process.
The KSTW-SR series modules are designed to use the main
magnetic component surface to allow for pick and place.
Note: All dimensions in mm [in].
Figure 18. Pick and Place Location.
Z Plane Height
The ‘Z’ plane height of the pick and place location is 7.50mm
nominal with an RSS tolerance of +/-0.25 mm.
Nozzle Recommendations
The module weight has been kept to a minimum by using open
frame construction. Even so, they have a relatively large mass
when compared with conventional SMT components.
Variables such as nozzle size, tip style, vacuum pressure and
placement speed should be considered to optimize this
process.
The minimum recommended nozzle diameter for reliable
operation is 5mm. The maximum nozzle outer diameter, which
will safely fit within the allowable component spacing, is
6.5mm.
Oblong or oval nozzles up to 11 x 6 mm may also be used
within the space available.
For further information please contact your local GE Technical
Sales Representative.
Reflow Soldering Information
These 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.
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. The
recommended linear reflow profile using Sn/Pb solder is
shown in Figure 19 and 20. For reliable soldering the solder
reflow profile should be established by accurately measuring
the module’s pin connector temperatures.
RE
FLOW TEM
P (
C)
REFLOW TIME (S)
Figure 19. Recommended Reflow Profile for Sn/Pb solder.
MAX TEM
P
SO
LD
ER (
C)
TIME LIMIT (S)
Figure 20. Time Limit, T
lim
, Curve Above 205 o C Reflow .
Lead Free Soldering
The –Z version SMT modules of the KSTW004A2B series are
lead-free (Pb-free) and RoHS compliant and are compatible in a
Pb-free soldering process. Failure to observe the instructions
below may result in the failure of or cause damage to the
modules and can adversely affect long-term reliability.
Pb-free Reflow Profile
Power Systems will comply with J-STD-020 Rev. C
(Moisture/Reflow Sensitivity Classification for Nonhermetic
Solid State Surface Mount Devices)
for both Pb-free solder profiles and MSL classification
procedures. This standard provides a recommended forced-
air-convection reflow profile based on the volume and
thickness of the package (table 4-2). The suggested Pb-free
solder paste is Sn/Ag/Cu (SAC). The recommended linear reflow
profile using Sn/Ag/Cu solder is shown in Figure 21.
0
50
100
150
200
250
300
P reheat zo ne
max 4
o Cs -1
So ak zo ne
30-240s
Heat zo ne
max 4
o Cs -1
P eak Temp 235 o C
Co o ling
zo ne
1-4
o Cs -1
T
lim
above
205 o C
200
205
210
215
220
225
230
235
240
0 10 20 30 40 50 60