JBW050F Power Modules: dc-dc Converter;
36 to 75 Vdc Input, 3.3 Vdc Output; 33 W
Data Sheet
September 20, 2004
Use Figure 20 to determine air velocity for the 1/2 inch heat sink.
The minimum airflow necessary for the JBW050F
module is 1.27 m/s (250 ft./min.).
Custom Heat Sinks
A more detailed model can be used to determine the required thermal resistance of a heat sink to provide neces-
sary cooling. The total module resistance can be separated into a resistance from case-to-sink (θcs) and sink-to-
ambient (θsa) shown below (Figure 21).
TC
TS
TA
PD
θcs
θsa
8-1304
Figure 21. Resistance from Case-to-Sink and
Sink-to-Ambient
For a managed interface using thermal grease or foils, a value of θcs = 0.1 °C/W to 0.3 °C/W is typical. The solution
for heat sink resistance is:
(TC – TA)
------------------------
PD
θsa =
– θcs
This equation assumes that all dissipated power must be shed by the heat sink. Depending on the user-defined
application environment, a more accurate model, including heat transfer from the sides and bottom of the module,
can be used. This equation provides a conservative estimate for such instances.
Solder, Cleaning, and Drying Considerations
Post solder cleaning is usually the final circuit-board assembly process prior to electrical testing. The result of inad-
equate circuit-board cleaning and drying can affect both the reliability of a power module and the testability of the
finished circuit-board assembly. For guidance on appropriate soldering, cleaning, and drying procedures, refer to
the Board-Mounted Power Modules Soldering and Cleaning Application Note (AP01-056EPS).
EMC Considerations
For assistance with designing for EMC compliance, please refer to the FLTR100V10 data sheet
(FDS01-043EPS).
Layout Considerations
Copper paths must not be routed beneath the power module mounting inserts. For additional layout guidelines,
refer to the FLTR100V10 data sheet
(FDS01-043EPS).
Tyco Electronics Power Systems
LINEAGEPOWER [ LINEAGE POWER CORPORATION ]
