JC100F1 Lineage Power, JC100F1 Datasheet - Page 14

• Manufacturer Part Number: JC100F1
• Manufacturer: Lineage Power

JC050F, JC075F, JC100F Power Modules: dc-dc Converters;
18 Vdc to 36 Vdc Input, 3.3 Vdc Output; 33 W to 66 W
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Thermal Considerations
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 28).
Figure 28. Resistance from Case-to-Sink and
P
D
→
Sink-to-Ambient
T
C
θcs
T
S
(continued)
θsa
T
A
8-1304
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:
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.
θ
sa
=
(
------------------------ -
T
C
P
–
D
T
A
)
–
θ
cs
Lineage Power
March 2008
Data Sheet