DS_H48SA12025_05052008
THERMAL CONSIDERATIONS
Thermal management is an important part of the
system design. To ensure proper, reliable operation,
sufficient cooling of the power module is needed over
the entire temperature range of the module. Convection
cooling is usually the dominant mode of heat transfer.
Hence, the choice of equipment to characterize the
thermal performance of the power module is a wind
tunnel.
Thermal Testing Setup
Delta’s DC/DC power modules are characterized in
heated vertical wind tunnels that simulate the thermal
environments encountered in most electronics
equipment. This type of equipment commonly uses
vertically mounted circuit cards in cabinet racks in which
the power modules are mounted.
The following figure shows the wind tunnel
characterization setup. The power module is mounted
on a test PWB and is vertically positioned within the
wind tunnel. The space between the neighboring PWB
and the top of the power module is constantly kept at
6.35mm (0.25’’).
Thermal Derating
Heat can be removed by increasing airflow over the
module. The module’s maximum device temperature is to
be defined and the measured location is illustrated in
Figure 24. To enhance system reliability, the power
module should always be operated below the maximum
operating temperature. If the temperature exceeds the
maximum module temperature, reliability of the unit may
be affected.
Note: Wind Tunnel Test Setup Figure Dimensions are in millimeters and (Inches)
12.7 (0.5”)
MODULE
IR FLOW
50.8
2.0”
FACING PWB
PWB
AIR VELOCIT
AND AMBIENT
TEMPERATURE
MEASURED BELOW
THE MODULE
Figure 23: Wind tunnel test setup
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