Thermal considerations, Air flow t – GE Industrial Solutions Austin Microlynx SIP User Manual

Page 15

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Data Sheet
July 2, 2010

Austin MicroLynx

TM

SIP Non-isolated Power Modules:

3 – 5.5Vdc input; 0.75Vdc to 3.63Vdc Output; 5A output current


LINEAGE

POWER

15

Thermal Considerations

Power modules operate in a variety of thermal
environments; however, sufficient cooling should be
provided to help ensure reliable operation.

Considerations include ambient temperature, airflow,
module power dissipation, and the need for increased
reliability. A reduction in the operating temperature of the
module will result in an increase in reliability. The thermal
data presented here is based on physical measurements
taken in a wind tunnel. The test set-up is shown in Figure
33. Note that the airflow is parallel to the long axis of the
module as shown in figure 32. The derating data applies
to airflow in either direction of the module’s long axis.

Air Flow

T

ref2

Top View

Bottom View

T

ref1

(inductor winding)

Figure 32. Tref Temperature measurement location.

The thermal reference point, T

ref 1

used in the

specifications of thermal derating curves is shown in
Figure 32. For reliable operation this temperature should
not exceed 125

o

C. The output power of the module

should not exceed the rated power of the module (Vo,set
x Io,max).
Please refer to the Application Note “Thermal
Characterization Process For Open-Frame Board-
Mounted Power Modules” for a detailed discussion of
thermal aspects including maximum device temperatures.

Figure 33. Thermal Test Set-up.

Heat Transfer via Convection

Increased airflow over the module enhances the heat
transfer via convection. Thermal derating curves showing
the maximum output current that can be delivered by
various module versus local ambient temperature (T

A

) for

natural convection and up to 1m/s (200 ft./min) are shown
in the Characteristics Curves section.

Layout Considerations

Copper paths must not be routed beneath the power
module. For additional layout guide-lines, refer to
FLTR100V10 application note.

Air

flow

x

Power Module

Wind Tunnel

PWBs

7.24_

(0.285)

76.2_

(3.0)

Probe Location
for measuring
airflow and
ambient
temperature

25.4_

(1.0)

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