AIF25R48_03 Datasheet, PDF (24/29 Pages) Astec America, Inc – Isolated DC/DC Converter Module

AIF25R48 Series Technical Reference Note
Thermal Management
Technologies
AIF25R48 series module has typical efficiency of 89% at full load. With less heat dissipation
and temperature-resistant components such as ceramic capacitors, the module exhibit good
behavior during pro-longed exposure to high temperatures. Maintaining the operating case
temperature (Tc) within the specified range help keep internal component temperatures
within their specifications, which in turn help keep MTBF from falling below the specified
rating. Proper cooling of the power modules is also necessary for reliable and consistent
operation.
Basic Thermal Management
Measuring the case temperature of the module (Tc) as the method shown in Figure 5 can
verify the proper cooling. The module should work under 55°C ambient for the reliability of
operation and Tc must not exceed 100°C while operating in the final system configuration.
The measurement can be made with a surface probe after the module has reached thermal
equilibrium. If a heat sink is mounted to the case, make the measurement as close as
possible to the indicated position. It makes the assumption that the final system configuration
exists and can be used for a test environment. Note that Tc of module must always be
checked in the final system configuration to verify proper operational due to the variation in
test conditions. Thermal management acts to transfer the heat dissipated by the module to
the surrounding environment. The amount of power dissipated by the module as heat (Pd) is
got by the equation below:
Pd = Pi ÄPo
where : Pi is input power; Po is output power; Pd is dissipated power.
Also, module efficiency ( ) is defined as the following equation:
= Po / Pi
If eliminating the input power term, from two above equations can yield the equation below:
Pd = Po (1- ) /
DATE: May 28, 2003
MODEL : AIF25R48 SERIES
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