JC050A1 Datasheet, PDF (12/16 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)
Heat Transfer Without Heat Sinks
Increasing airflow over the module enhances the heat
transfer via convection. Figure 24 shows the maximum
power that can be dissipated by the module without
exceeding the maximum case temperature versus local
ambient temperature (TA) for natural convection
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 24 is
shown in the following example.
12
11
10
9
VI = 36 V
VI = 27 V
8
VI = 18 V
7
6
5
4
12345678
OUTPUT CURRENT, IO (A)
Figure 25. JC050A Power Dissipation vs.
Output Current
9 10
8-2220
Example
What is the minimum airflow necessary for a JC100A
operating at nominal line, an output current of 20 A,
and a maximum ambient temperature of 40 °C?
Solution
Given: VI = 28 V
IO = 20 A
TA = 40 °C
Determine PD (Use Figure 27.):
PD = 22.8 W
Determine airflow (v) (Use Figure 24.):
v = 2.7 m/s (540 ft./min.)
35
4.0 m/(s800 ft./min
3.5 m/(s700 ft./min
30
3.0 m/(s600 ft./min
2.5 m(/5s00 ft./min
25
2.0 m(/4s00 ft./min
1.5 m/(s300 ft./min
20
1.0 m/(s200 ft./min
0.5 m/(s100 ft./min
15
10
5
0.1 m/s (NAT. CONV.)
(20 ft./min.)
0
0 10 20 30 40 50 60 70 80 90 100
LOCAL AMBIENT TEMPERATURE, TA (˚C)
8-1150 (C).a
Figure 24. Forced Convection Power Derating with
No Heat Sink; Either Orientation
20
18
16
14
VI = 18 V
VI = 28 V
12
VI = 36 V
10
8
6
4
2
0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
OUTPUT CURRENT, I O (A)
Figure 26. JC075A Power Dissipation vs.
Output Current
8-1604
24
22
20
18
16
14
12
10
8
6
4
2
0
02
VI = 36 V
VI = 28 V
VI = 18 V
4 6 8 10 12 14 16 18 20
OUTPUT CURRENT, I O (A)
Figure 27. JC100A Power Dissipation vs.
Output Current
8-1605
12
Lineage Power