JFW050B1 Lineage Power, JFW050B1 Datasheet - Page 18

• Manufacturer Part Number: JFW050B1
• Description: CONVERTER DC/DC 12V 50W OUT
• Manufacturer: Lineage Power
• Series: JFWr
• Type: Isolatedr

Specifications of JFW050B1

• Output: 12V
• Number Of Outputs: 1
• Power (watts): 50W
• Mounting Type: Through Hole
• Voltage - Input: 36 ~ 75V
• Package / Case: Module
• 1st Output: 12 VDC @ 4.2A
• 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: 85%
• 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, 12 Vdc Output; 50 W to 150 W
Thermal Considerations
Heat Transfer with Heat Sinks
Figure 33. Case-to-Ambient Thermal Resistance
Example
If an 85 °C case temperature is desired, what is the
minimum airflow necessary? Assume the JFW150B
module is operating at V
of 10 A, maximum ambient air temperature of 40 °C,
and heat sink of 0.5 in.
Solution
Given: V
Determine P
Then solve the following equation:
18
18
θ
θ
θ
ca
ca
ca
8
7
6
5
4
3
2
1
0
0
I
T
T
Heat sink = 0.5 inch.
P
O
=
=
=
A
C
I
D
= 54 V
= 10 A
= 40 °C
= 85 °C
Curves; Either Orientation
= 17 W
2.6 °C/W
D
(
----------------------- -
(
----------------------- -
(100)
T
85 40
0.5
by using Figure 32:
C
P
17
–
–
D
AIR VELOCITY, IN m/s (ft./min.)
T
A
(200)
)
)
1.0
I
= 54 V and an output current
(300)
1.5
1 1/2 IN. HEAT SINK
1 IN. HEAT SINK
1/2 IN. HEAT SINK
1/4 IN. HEAT SINK
NO HEAT SINK
(continued)
(400)
2.0
(continued)
(500)
2.5
8-1153 (C).a
(600)
3.0
Use Figure 33 to determine air velocity for the 0.5 inch
heat sink. The minimum airflow necessary for this
module is about 1.25 m/s (250 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) shown below (Figure 34).
Figure 34. Resistance from Case-to-Sink and
For a managed interface using thermal grease or foils,
a value of θcs = 0.1 °C/W to 0.3 °C/W is typical. The
solution for heat sink resistance is:
This equation assumes that all dissipated power must
be shed by the heat sink. Depending on the user-
defined application environment, a more accurate
model, including heat transfer from the sides and bot-
tom of the module, can be used. This equation pro-
vides a conservative estimate for such instances.
EMC Considerations
For assistance with designing for EMC compliance,
please refer to the FLTR100V10 data sheet
(DS99-294EPS).
Layout Considerations
Copper paths must not be routed beneath the power
module mounting inserts. For additional layout guide-
lines, refer to the FLTR100V10 data sheet
(DS99-294EPS).
θ
sa
P
=
D
∅
Sink-to-Ambient
(
------------------------ -
T
C
P
T
–
C
D
T
A
)
–
θcs
θ
cs
T
S
θsa
Lineage Power
April 2008
T
A
8-1304 (C)