JAW050A and JAW075A Power Modules; dc-dc Converters:
36 Vdc to 75 Vdc Input, 5 Vdc Output; 50 W to 75 W
Data Sheet
April 2008
Thermal Considerations
(continued)
Heat Transfer Without Heat Sinks
(continued)
20
POWER DISSIPATION, P
D
(W)
18
16
14
12
10
0.1 m/s
8 (20 ft./min.)
1.0 m/s
6 (200 ft./min.)
4
2.0 m/s
(400 ft./min.)
2
0
0
10
20
30
40
50
60
70
80
90 100
LOCAL AMBIENT TEMPERATURE, T
A
(°C)
8-2465(F)
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 (ΔT
C, max
) divided by the
module power dissipation (P
D
):
(
T
C
–
T
A
θ
ca
=
ΔT
C, max
=
-----------------------
)
--------------------
-
-
P
D
P
D
The location to measure case temperature (T
C
) is
shown in Figure 18. Case-to-ambient thermal resis-
tance vs. airflow for various heat sink configurations
and heights is shown in Figures 23 and 24. These
curves were obtained by experimental testing of heat
sinks, which are offered in the product catalog.
9
CASE-TO-AMBIENT THERMAL
RESISTANCE,
θ
CA
(°C/W)
8
7
6
5
4
3
2
1
0
0
0.5
(100)
1.0
(200)
1.5
(300)
2.0
(400)
2.5
(500)
3.0
(600)
NO HEAT SINK
1/4 IN. HEAT SINK
1/2 IN. HEAT SINK
1 IN. HEAT SINK
1 1/2 IN. HEAT SINK
3.0 m/s
(600 ft./min.)
4.0 m/s
(800 ft./min.)
Figure 21. Forced Convection Power Derating with
No Heat Sink; Longitudinal Orientation
20
POWER DISSIPATION, P
D
(W)
18
16
14
12
10
8
6
4
0
0
10
20
30
40
50
60
70
80
90 100
8-2466(F)
3.0 m/s
(600 ft./min.)
4.0 m/s
(800 ft./min.)
AIR VELOCITY, m/s (ft./min.)
8-2164(F).a
0.1 m/s
(20 ft.min.)
1.0 m/s
(200 ft./min.)
Figure 23. Case-to-Ambient Thermal Resistance
Curves; Longitudinal Orientation
CASE-TO-AMBIENT THERMAL
RESISTANCE,
θ
CA
(°C/W)
2.0 m/s
2 (400 ft./min.)
8
7
6
5
4
3
2
1
0
0
0.5
(100)
1.0
(200)
1.5
(300)
2.0
(400)
2.5
(500)
3.0
(600)
NO HEAT SINK
1/4 IN. HEAT SINK
1/2 IN. HEAT SINK
1 IN. HEAT SINK
1 1/2 IN. HEAT SINK
LOCAL AMBIENT TEMPERATURE, T
A
(°C)
Figure 22. Forced Convection Power Derating with
No Heat Sink; Transverse Orientation
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.).
AIR VELOCITY, m/s (ft./min.)
8-2165(F).a
Figure 24. Case-to-Ambient Thermal Resistance
Curves; Transverse Orientation
12
Lineage Power
LINEAGEPOWER [ LINEAGE POWER CORPORATION ]
