QHW075F1-Q Lineage Power, QHW075F1-Q Datasheet - Page 16

• Manufacturer Part Number: QHW075F1-Q
• Description: CONVRTR DC/DC 3.3V 49.5W OUT
• Manufacturer: Lineage Power
• Series: QHWr
• Type: Isolated with Remote On/Offr

Specifications of QHW075F1-Q

• Output: 3.3V
• Number Of Outputs: 1
• Power (watts): 50W
• Mounting Type: Through Hole
• Voltage - Input: 36 ~ 75V
• Package / Case: 8-DIP Module
• 1st Output: 3.3 VDC @ 15A
• Size / Dimension: 2.28" L x 1.45" W x 0.50" H (57.9mm x 36.8mm x 12.7mm)
• Power (watts) - Rated: 50W
• Operating Temperature: -40°C ~ 100°C
• Efficiency: 81%
• Approvals: CE, CSA, UL, VDE
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• 3rd Output: -
• 2nd Output: -
• 4th Output: -

QHW050F1-Q, QHW075F1-Q, and QHW100F1-Q Power Modules;
dc-dc Converters: 36 to 75 Vdc Input, 3.3 Vdc Output; 33 W to 66 W
Thermal Considerations
Heat Transfer with Heat Sinks
Example
If an 85 °C case temperature is desired, what is the
minimum airflow necessary? Assume the
QHW100F1-Q module is operating at V
output current of 20 A, maximum ambient air tempera-
ture of 40 °C, and the heat sink is 1/2 inch. The module
is oriented in the transverse direction.
Solution
Given: V
Determine P
Then solve the following equation:
Use Figure 30 to determine air velocity for the 1/2 inch
heat sink.
The minimum airflow necessary for this module is
0.75 m/s (150 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 36.
16
16
θ
θ
θ
ca
ca
ca
I
T
T
Heat sink = 1/2 inch
P
O
=
=
=
A
C
I
D
= 48 V
= 20 A
= 40 °C
= 85 °C
= 11.5 W
3.91 °C/W
D
(
----------------------- -
(
----------------------- -
T
85 40
by using Figure 29:
C
11.5
P
–
–
D
T
A
)
)
(continued)
(continued)
I
= 48 V and an
Figure 36. 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 Filter Module 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 Filter Module Data
Sheet (DS99-294EPS).
θ
sa
=
P
D
(
------------------------ -
Sink-to-Ambient
T
C
T
P
–
C
D
T
A
)
–
θ
θ
cs
cs
T
S
θ
sa
Lineage Power
Data Sheet
April 2008
T
A
8-1304(F).e