JAHW075F1 Lineage Power, JAHW075F1 Datasheet - Page 14

• Manufacturer Part Number: JAHW075F1
• Description: CONVERTER DC/DC 3.3V 50W OUT
• Manufacturer: Lineage Power
• Series: JAHWr
• Type: Isolated with Remote On/Offr

Specifications of JAHW075F1

• Output: 3.3V
• Number Of Outputs: 1
• Power (watts): 50W
• Mounting Type: Through Hole
• Voltage - Input: 36 ~ 75V
• Package / Case: 9-DIP Module
• 1st Output: 3.3 VDC @ 15A
• Size / Dimension: 2.40" L x 2.28" W x 0.50" H (61mm x 57.9mm x 12.7mm)
• Power (watts) - Rated: 50W
• Operating Temperature: -40°C ~ 100°C
• Efficiency: 88.6%
• Approvals: CE, CSA, UL, VDE
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• 3rd Output: -
• 2nd Output: -
• 4th Output: -

dc-dc Converters; 36 to 75 Vdc Input, 3.3 Output; 33 W to 66 W
Thermal Considerations
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 (ΔT
module power dissipation (P
The location to measure case temperature (T
shown in Figure 23. Case-to-ambient thermal resis-
tance vs. airflow is shown, for various heat sink config-
urations and heights, in Figure 28. These curves were
obtained by experimental testing of heat sinks, which
are offered in the product catalog.
Figure 28. Case-to-Ambient Thermal Resistance
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 Figure 28 had a
thermal-conductive dry pad between the case and the
heat sink to minimize contact resistance. The use of
Figure 28 is shown in the following example.
14
14
θ
ca
8
7
6
5
4
3
2
1
0
0.0
=
(0)
Curves; Either Orientation
ΔT
-------------------- -
(100)
P
0.5
C max
,
D
AIR VELOCITY, m/s (ft./min.)
(200)
1.0
=
(
----------------------- -
T
D
(300)
C
1.5
):
P
–
D
C, max
T
A
(continued)
1 1/2 IN. HEAT SINK
1 IN. HEAT SINK
1/2 IN. HEAT SINK
1/4 IN. HEAT SINK
NO HEAT SINK
)
(400)
2.0
) divided by the
(500)
2.5
C
) is
(600)
3.0
8-2505 (F)
Example
If an 85 °C case temperature is desired, what is the
minimum airflow necessary? Assume the JAHW100F
module is operating at V
of 20 A, maximum ambient air temperature of 55 °C,
and the heat sink is 1/4 inch.
Solution
Given: V
Determine P
Then solve the following equation:
Use Figure 28 to determine air velocity for the 1/4 inch
heat sink.
The minimum airflow necessary for the JAHW100F
module is 1.12 m/s (220 ft./min.).
Custom Heat Sinks
A more detailed model can be used to determine the
required thermal resistance of a heat sink to provide
necessary cooling. The total module resistance can be
separated into a resistance from case-to-sink (θcs) and
sink-to-ambient (θsa) as shown in Figure 29.
Figure 29. Resistance from Case-to-Sink and
θ
θ
θ
ca
ca
ca
I
T
T
Heat sink = 1/4 inch
P
O
P
=
=
=
A
C
I
D
D
= 20 A
= 48 V
= 55 °C
= 85 °C
= 8.0 W
Sink-to-Ambient
3.75 °C/W
D
(
----------------------- -
(
----------------------- -
T
85 55
by using Figure 27:
T
C
8.0
P
C
–
–
D
T
A
)
)
θcs
I
= 48 V and an output current
T
S
θsa
Lineage Power
April 2008
T
A
8-1304 (F).e