DS_s48SS12001_06082006
9
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 or a heat sink is
6.35mm (0.25”).
Thermal Derating
Heat can be removed by increasing airflow over the
module. Figure 13 and 14 show maximum output is a
function of ambient temperature and airflow rate. The
module’s maximum case temperature is +100°C. 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.
Figure 19: Wind tunnel test setup
Note: Wind Tunnel Test Setup Figure Dimensions are in millimeters and (Inches)
10 (0.4”)
MODULE
IR FLOW
50.8
2.0”
FACING PWB
PWB
AIR VELOCIT
AND AMBIENT
TEMPERATURE
MEASURED BELOW
THE MODULE
