JC050B Datasheet, PDF (11/16 Pages) List of Unclassifed Manufacturers – JC050B

Data Sheet
October 1997
JC050B, JC075B, JC100B Power Modules: dc-dc Converters;
18 Vdc to 36 Vdc Input, 12 Vdc Output; 50 W to 100 W
Thermal Considerations (continued)
Introduction (continued)
7.6 (0.3)
38.0 (1.50)
VI(+)
ON/OFF
CASE
VI(–)
MEASURE CASE
TEMPERATURE HERE
VO(+)
+ SEN
TRIM
– SEN
VO(–)
Example
What is the minimum airflow necessary for a JC100B
operating at nominal line, an output current of 8.5 A,
and a maximum ambient temperature of 40 °C?
Solution
Given: VI = 28 V
IO = 8.5 A
TA = 40 °C
Determine PD (Use Figure 24.):
PD = 20 W
Determine airflow (v) (Use Figure 21.):
v = 2.5 m/s (500 ft./min.)
Note: Top view, pin locations are for reference.
Measurements shown in millimeters and (inches).
8-716 (C).f
Figure 20. Case Temperature Measurement
Location
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).
35
4.0 m/s(800 ft./min.)
3.5 m/s(700 ft./min.)
30
3.0 m/s(600 ft./min.)
2.5 m/s(500 ft./min.)
25
2.0 m/s(400 ft./min.)
1.5 m/s(300 ft./min.)
20
1.0 m/s(200 ft./min.)
0.5 m/s(100 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 21. Forced Convection Power Derating with
No Heat Sink; Either Orientation
Heat Transfer Without Heat Sinks
Increasing airflow over the module enhances the heat
transfer via convection. Figure 21 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 Figur e21 is
shown in the following example.
12
10
VI = 18
8
VI = 27
VI = 36
6
4
2
0
0.0
0.6
1.2 1.8
2.4 3.0
3.6 4.2
OUTPUT CURRENT, IO (A)
Figure 22. JC050B Power Dissipation vs.
Output Current
8-1249
Tyco Electronics Corp.
11