JFW100G Lineage Power, JFW100G Datasheet - Page 15

• Manufacturer Part Number: JFW100G
• Manufacturer: Lineage Power

April 2008
Thermal Considerations
Heat Transfer Without Heat Sinks
Increasing airflow over the module enhances the heat
transfer via convection. Figure 22 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 this power module may be
used typically generate a natural convection airflow
rate of 0.3 m/s (60 ft./min.) due to other heat dissipating
components in the system. The use of Figure 22 is
shown in the following example.
Example
What is the minimum airflow necessary for a JFW150G
operating at V
maximum ambient temperature of 40 °C?
Solution
Given: V
Determine P
Determine airflow (v) (Use Figure 22.):
Lineage Power
I
T
P
v = 3.2 m/s (630 ft./min.)
O
A
I
D
= 30 A
= 54 V
= 40 °C
= 24 W
D
I
(Use Figure 24.):
= 54 V, an output current of 30 A, and a
A
) for natural convection
dc-dc Converters; 36 to 75 Vdc Input; 2.5 Vdc Output; 25 W to 75 W
(continued)
Figure 22. Forced Convection Power Derating with
Figure 23. JFW100G Power Dissipation vs. Output
18
16
14
12
10
35
30
25
20
15
10
8
6
4
2
0
5
0
2
0
0.1 m/s (NAT. CONV.)
No Heat Sink; Either Orientation
Current at 80 °C
10
4
V
V
LOCAL AMBIENT TEMPERATURE, T
I
I
= 75 V
= 48 V
20
6
OUTPUT CURRENT, I
(20 ft./min.)
30
8
40
10
50
12
60
O
14
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
2.0 m/s
1.5 m/s (300 ft./min
1.0 m/s (200 ft./min
0.5 m/s (100 ft./min
V
(A)
I
70
= 36 V
16
(500 ft./min
(400 ft./min
A
80
(˚C)
18
8-1150 (C).a
90
8-2524(C)
20
100
15