JW075C Lineage Power, JW075C Datasheet - Page 13

• Manufacturer Part Number: JW075C
• Manufacturer: Lineage Power

April 2008
Thermal Consideration
Introduction
Although the maximum case temperature of the power
modules is 100 °C, you can limit this temperature to a
lower value for extremely high reliability.
For additional information on these modules, refer to
the Thermal Management JC-, JFC-, JW-, and JFW-
Series 50 W to 150 W Board-Mounted Power Modules
Technical Note
(TN97-008EPS).
Heat Transfer Without Heat Sinks
Increasing airflow over the module enhances the heat
transfer via convection. Figure 27 shows the maximum
power that can be dissipated by the module without
exceeding the maximum case temperature versus local
ambient temperature (T
through 4 m/s (800 ft./min.).
Note that the natural convection condition was mea-
sured at 0.05 m/s to 0.1 m/s (10 ft./min. to 20 ft./min.);
however, systems in which these power modules may
be used typically generate natural convection airflow
rates of 0.3 m/s (60 ft./min.) due to other heat dissipat-
ing components in the system. The use of Figure 27 is
shown in the following example.
Example
What is the minimum airflow necessary for a JW100C
operating at V
maximum ambient temperature of 40 °C?
Solution
Given: V
Determine P
Determine airflow (v) (Use Figure 27.):
Lineage Power
I
T
P
v = 1.3 m/s (260 ft./min.)
O
A
I
D
= 6.7 A
= 54 V
= 40 °C
= 14 W
D
I
(Use Figure 30.):
= 54 V, an output current of 6.7 A, and a
(continued)
A
) for natural convection
dc-dc Converters; 36 to 75 Vdc Input, 15 Vdc Output; 50 W to 150 W
(continued)
Figure 27. Forced Convection Power Derating with
Figure 28. JW050C Power Dissipation vs.
35
30
25
20
15
10
5
0
12
10
0
8
6
4
2
0
0.0
No Heat Sink; Either Orientation
Output Current
0.1 m/s (NAT. CONV.)
10
0.3
LOCAL AMBIENT TEMPERATURE, T
20
0.6
V
V
V
(20 ft./min.)
I
I
I
0.9
= 72 V
= 54 V
= 36 V
30
OUTPUT CURRENT, I
1.2
40
1.5
50
1.8
60
2.1
4.0 m/s (800 ft./min.)
3.5 m/s (700 ft./min.)
3.0 m/s (600 ft./min.)
2.5 m/s (500 ft./min.)
2.0 m/s (400 ft./min.)
1.5 m/s (300 ft./min.)
1.0 m/s (200 ft./min.)
0.5 m/s (100 ft./min.)
O
(A)
70
2.4
A
80
(°C)
2.7
8-1150 (C).a
3.0
90
8-1441 (C)
100
3.3
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