JC050H Lineage Power, JC050H Datasheet - Page 11

• Manufacturer Part Number: JC050H
• Manufacturer: Lineage Power

March 2008
Thermal Considerations
Introduction
Note: Top view, pin locations are for reference.
Figure 20. Case Temperature Measurement
The temperature at this location should not exceed
100 °C. The output power of the module should not
exceed the rated power for the module as listed in the
Ordering Information table.
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).
Lineage Power
7.6 (0.3)
Measurements shown in millimeters and (inches).
Location
V
ON/OFF
CASE
V
I
I
(continued)
(+)
(–)
38.0 (1.50)
dc-dc Converters; 18 to 36 Vdc Input, 24 Vdc Output; 50 W to 100 W
+ SEN
– SEN
V
TRIM
V
O
O
(+)
(–)
(continued)
MEASURE CASE
TEMPERATURE HERE
8-716 (C).f
Heat Transfer Without Heat Sinks
Increasing airflow over the module enhances the heat
transfer via convection. Title 21 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 Title 21 is
shown in the following example.
Example
What is the minimum airflow necessary for a JC100H
operating at nominal line, an output current of 4.2 A,
and a maximum ambient temperature of 40 °C?
Solution
Given: V
Determine P
Determine Airflow (v) (Use Title 21.):
Figure 21. Forced Convection Power Derating with
35
30
25
20
15
10
5
0
0
I
T
P
v = 1.75 m/s (350 ft./min.)
O
A
I
D
= 28 V
= 4.2 A
= 40 °C
= 16 W
0.1 m/s (NAT. CONV.)
10
No Heat Sink; Either Orientation
D
(Use Title 24.):
LOCAL AMBIENT TEMPERATURE, T
20
(20 ft./min.)
30
A
) for natural convection
40
50
60
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
70
(500 ft./min
(400 ft./min
A
80
(˚C)
90
8-1150 (C)
100
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