JC050B Datasheet, PDF (12/16 Pages) List of Unclassifed Manufacturers – JC050B

JC050B, JC075B, JC100B Power Modules: dc-dc Converters;
18 Vdc to 36 Vdc Input, 12 Vdc Output; 50 W to 100 W
Data Sheet
October 1997
Thermal considerations (continued)
Heat Transfer Without Heat Sinks (continued)
20
18
16
14
VI = 36 V
12
VI = 24 V
VI = 18 V
10
8
6
4
2
0
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5
OUTPUT CURRENT, IO (A)
Figure 23. JC075B Power Dissipation vs.
Output Current
8-1494
25
20
VI = 18
VI = 28
15
VI = 36
10
5
0
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0
OUTPUT CURRENT, IO (A)
Figure 24. JC100B Power Dissipation vs.
Output Current
8.0
8-1250
Heat Transfer with Heat Sinks
The power modules have through-threaded, M3 x 0.5
mounting holes, which enable heat sinks or cold plates
to attach to the module. The mounting torque must not
exceed 0.56 N-m (5 in.-lb.).
Thermal derating with heat sinks is expressed by using
the overall thermal resistance of the module.Total
module thermal resistance (θca) is defined as the max-
imum case temperature rise (∆TC, max) divided by the
module power dissipation (PD):
θca = ^∆----^T----^C---^,--^m----^a---^x = ⁽---T----^C----^–-----T----^A----⁾
PD
PD
The location to measure case temperature (TC) is
shown in Figure 20. Case-to-ambient thermal resis-
tance vs. airflow is shown, for various heat sink config-
urations and heights, in Figur e25. These curves were
obtained by experimental testing of heat sinks, which
are offered in the product catalog.
8
7
1 1/2 IN HEAT SINK
6
1 IN HEAT SINK
1/2 IN HEAT SINK
5
1/4 IN HEAT SINK
NO HEAT SINK
4
3
2
1
0
0
0.5
1.0
1.5
2.0
2.5 3.0
(100) (200) (300) (400) (500) (600)
AIR VELOCITY MEASURED IN m/s (ft./min.)
8-1153
Figure 25. Case-to-Ambient Thermal Resistance
Curves; Either Orientation
These measured resistances are from heat transfer
from the sides and bottom of the module as well as the
top side with the attached heat sink; therefore, the
case-to-ambient thermal resistances shown are gener-
ally lower than the resistance of the heat sink by itself.
The module used to collect the data in Figur e25 had a
thermal-conductive dry pad between the case and the
heat sink to minimize contact resistance. The use of
Figure 25 is shown in the following example
12
Tyco Electronics Corp.