JW075R Lineage Power, JW075R Datasheet - Page 18

• Manufacturer Part Number: JW075R
• Manufacturer: Lineage Power

dc-dc Converters; 36 to 75 Vdc Input, 28 Vdc Output; 50 W to 150
Thermal Considerations
Heat Transfer with Heat Sinks
Then solve the following equation:
Use Figure 41 to determine air velocity for the 1/2 inch
heat sink.
The minimum airflow necessary for the JW150R1
module is 1.07 m/s (210 ft./min.).
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 42).
Figure 42. Resistance from Case-to-Sink and
18
18
θ
θ
θ
ca
ca
ca
∅
=
=
=
T
3.0 °C/W
Sink-to-Ambient
C
(
----------------------- -
(
----------------------- -
T
85 40
C
14.8
P
–
–
D
T
θ
A
cs
)
)
T
S
θ
(continued)
sa
(continued)
T
A
8-1304 (C)
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.
EMC Considerations
For assistance with designing for EMC compliance,
please refer to the FLTR100V10 data sheet
(DS99-294EPS).
Layout Considerations
Copper paths must not be routed beneath the power
module mounting inserts. For additional layout guide-
lines, refer to the FLTR100V10 data sheet
(DS99-294EPS).
θsa
=
(
----------------------- -
T
C
P
–
D
T
A
)
–
θcs
Lineage Power
April 2008