Datasheet

3
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 filter 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 filter 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 6.35mm (0.25”).
Thermal Derating
Heat can be removed by increasing airflow over the
module. Figure 4 shows maximum output is a function of
ambient temperature and airflow rate. 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)
10 (0.4”)
MODULE
A
IR FLOW
50.8
(
2.0”
)
FACING PWB
PWB
A
IR VELOCIT
Y
A
ND AMBIENT
TEMPERATURE
MEASURED BELOW
THE MODULE
Figure 4: Wind tunnel test setup figure dimensions are
in millimeters and (inches).
OUT
GND
16 mm
(0.63 in)
27 mm
(1.06 in)
Figure 5: Temperature measurement location
The allowed maximum hot spot temperature is defined at 110
℃
FL75L20 (Standard) Output Current vs. Ambient Temperature and Air Velocity
@ Vin = 48V (Either Orientation)
0
5
10
15
20
25
25 35 45 55 65 75 85
Ambient Temperature (℃)
Output Current(A)
Natural
Convection
100LFM
200LFM
300LFM
400LFM
500LFM
600LFM
Figure 6: Output Current vs. Ambient Temperature and Air
Velocity @ Vin = 48V (Either Orientation)