JC050A1 Datasheet, PDF (14/16 Pages) Lineage Power Corporation – Small size: 61.0 mm x 57.9 mm x 12.7 mm (2.40 in. x 2.28 in. x 0.50 in.)

JC050A, JC075A, JC100A Power Modules: dc-dc Converters;
18 Vdc to 36 Vdc Input, 5 Vdc Output; 50 W to 100 W
Data Sheet
March 2008
Thermal Considerations (continued)
Custom Heat Sinks
A more detailed model can be used to determine the
required thermal resistance of a heat sink to provide
necessary cooling. The total module resistance can be
separated into a resistance from case-to-sink (θcs) and
sink-to-ambient (θsa) shown below (Figure 29).
TC
TS
TA
PD ^→
θcs
θsa
8-1304
Figure 29. 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:
θsa = ⁽---T----^C--P---^–--_D--T----^A----⁾ – 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 bot-
tom of the module, can be used. This equation pro-
vides a conservative estimate for such instances.
Layout Considerations
Copper paths must not be routed beneath the power
module mounting inserts.
14
Lineage Power