Construction And Reliability; Thermal Considerations - Dynamic Engineering PMC-XM-DIFF User Manual

Construction and Reliability

PMC Modules were conceived and engineered for rugged industrial environments. The
PMC-XM is constructed out of 0.062-inch thick FR4 material.
Surface-mount components are used. The PMC connectors are rated at 1 Amp per pin,
100 insertion cycles minimum. These connectors make consistent, correct insertion
easy and reliable.
The PMC is secured against the carrier with four screws attached to the 2 stand-offs
and 2 locations on the front panel. The four screws provide significant protection
against shock, vibration, and incomplete insertion.
The PMC Module provides a low temperature coefficient of 2.17 W/°C for uniform heat.
This is based upon the temperature coefficient of the base FR4 material of 0.31 W/m-
°C, and taking into account the thickness and area of the PMC. The coefficient means
that if 2.17 Watts are applied uniformly on the component side, then the temperature
difference between the component side and solder side is one degree Celsius.

Thermal Considerations

The PMC-XM design consists of CMOS circuits. The power dissipation due to internal
circuitry is very low. It is possible to create higher power dissipation with the externally
connected logic. If more than one Watt is required to be dissipated due to external
loading, then forced-air cooling is recommended. With the one degree differential
temperature to the solder side of the board, external cooling is easily accomplished.
Embedded Solutions
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