Data Sheet
FNW500R Power Modules; DC-DC Converters
36 – 75 Vdc Input; 28Vdc Output; 500W Output
September 8, 2008
Thermal Considerations
600
500
400
300
200
100
0
The power modules operate in a variety of thermal
environments; however, sufficient cooling should be
provided to help ensure reliable operation of the unit.
Heat-dissipating components inside the unit are
thermally coupled to the case. Heat is removed by
conduction, convection, and radiation to the
surrounding environment. Proper cooling can be
verified by measuring the case temperature. Peak
temperature (TC) occurs at the position indicated in
Figure 14.
60
65
70
75
80
85
90
95
100
Considerations include ambient temperature, airflow,
module power dissipation, and the need for increased
reliability. A reduction in the operating temperature of
the module will result in an increase in reliability. The
thermal data presented here is based on physical
measurements taken in a wind tunnel.
Tcase (C)
Figure 15. Output Power Derating for FNW500R in
Conduction cooling (cold plate) applications;
Ta <72ºC in vicinity of module interior; VIN = VIN, NOM
Layout Considerations
For reliable operation this temperature should not
exceed 100ºC.
The FNW500R power module series are aluminum
base board packaged style, as such; component
clearance between the bottom of the power module
and the mounting (Host) board is limited. Avoid placing
copper areas on the outer layer directly underneath the
power module.
TOP VIEW
Post Solder Cleaning and Drying
Considerations
Post solder cleaning is usually the final circuit-board
assembly process prior to electrical board testing. The
result of inadequate cleaning and drying can affect both
the reliability of a power module and the testability of
the finished circuit-board assembly. For guidance on
appropriate soldering, cleaning and drying procedures,
refer to Lineage Power Board Mounted Power
23mm
45mm
Figure 14. Case (Tc ) Temperature Measurement
Location (top view).
Modules: Soldering and Cleaning Application Note.
The output power of the module should not exceed the
rated power for the module as listed in the ordering
Information table.
Although the maximum Tc temperature of the power
modules is 100°C, you can limit this temperature to a
lower value for extremely high reliability.
Thermal Derating
The curve in Figure 15 depicts the temperature/output
power derating curve for conduction cooling type
applications. These applications typically will provide a
low thermal impedance cooling interface that is
attached to the top surface of the module and is
maintained at or below the TC temperature. The internal
air surrounding the module is still and is held below
72°C. The module will deliver full power when the case
(TC) Temperature Measurement Location is maintained
at or below 95°C. For temperatures above 95°C, the
output current must be limited by the derating curve.
For other applications, such as force air cooling, the
FNW500R power module has large power dissipation,
a customized heatsink is required for application.
LINEAGE POWER
10
LINEAGEPOWER [ LINEAGE POWER CORPORATION ]
