Thermal Considerations; Thermal Curves - Delta Electronics Delphi S24SA Datasheet

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
equipment. This type of equipment commonly uses
vertically mounted circuit cards in cabinet racks in which
the power modules are mounted.
The following figure
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. The module's maximum hot spot temperature is
110℃. 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.
FACING PWB
AIR VELOCITY
AND AMBIENT
TEMPERATURE
MEASURED BELOW
THE MODULE
Note: Wind Tunnel Test Setup Figure Dimensions are in millimeters and (Inches)
Figure 17: Wind tunnel test setup figure
DS_S24SA1R812_05092006
in most electronics
shows the wind tunnel
PWB
MODULE
50.8 (2.0")
AIR FLOW
10 (0.4")

THERMAL CURVES

Figure 18: Hot spot temperature measured point
The allowed maximum hot spot temperature is defined at 110
＊
S24SA1R812NR (Standard) Output Current vs. Ambient Temperature and Air Velocity
Output Current(A)
12
10
Natural
Convection
7
100LFM
200LFM
5
300LFM
400LFM
2
500LFM
0
50 55 60
Figure 19: Output current vs. ambient temperature and air velocity
(Either Orientation)
(Either Orientation)
65 70 75 80
Ambient Temperature (℃)
℃
85
9