Q48SA52001NNFA Datasheet, PDF (9/12 Pages) Delta Electronics, Inc. – Delphi Series Q48SA, 60W Quarter Brick Family DC/DC Power Modules: 36~75V in, 52V/1.15A out

Figure 17: Circuit configuration for trim-down (decrease
output voltage)
If the external resistor is connected between the TRIM
and Vo(+), Vout decreases (Fig. 18). The external
resistor value required to obtain output voltage change
△U is defined as:
R_{trim − down}
=
51* 51 _{− 55.7(KΩ)}
ΔU
Ex. When Trim-down 15%，△U is
15%*Vnormal=0.15*52.5=7.875
R_{trim −down}
=
51* 51
7.875
− 55.7
=
274.6(KΩ)
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’’).
When using trim-up, the output voltage of the module
is usually increased, which increases the power output
of the module with the same output current.Care
should be taken to ensure that the maximum output
power of the module remains at or below the maximum
rated power.
FACING PWB
PWB
MODULE
AIR VELOCITY
AND AMBIENT
TEMPERATURE
MEASURED BELOW
THE MODULE
AIR FLOW
50.8 (2.0”)
12.7 (0.5”)
Note: Wind Tunnel Test Setup Figure Dimensions are in millimeters and (Inches)
Figure 18: Wind tunnel test setup
Thermal Derating
Heat can be removed by increasing airflow over the
module. 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.
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