Motorola 700/800-Series Manuel D’Utilisation

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Board Level Hardware Description
1
Cooling Requirements
The Motorola MVME162LX VME Embedded Controller is 
specified, designed, and tested to operate reliably with an incoming 
air temperature range from 0û to 55û C (32û to 131û F) with forced air 
cooling at a velocity typically achievable by using a 100 CFM axial 
fan. Temperature qualification is performed in a standard Motorola 
VME system chassis. Load boards are inserted adjacent to the board 
under test, to simulate a high power density system configuration. 
An assembly of three axial fans, rated at 100 CFM per fan, is placed 
directly under the VME card cage. The incoming air temperature is 
measured between the fan assembly and the card cage, where the 
incoming airstream first encounters the controller under test. Test 
software is executed as the controller is subjected to ambient 
temperature variations. Case temperatures of critical, high power 
density integrated circuits are monitored to ensure that component 
vendorsÕ specifications are not exceeded.
While the exact amount of airflow required for cooling depends on 
the ambient air temperature and the type, number, and location of 
boards and other heat sources, adequate cooling can usually be 
achieved with 10 CFM and 490 LFM flowing over the controller. 
Less airflow is required to cool the controller in environments 
having lower maximum ambients. Under more favorable thermal 
conditions (refer to Elevated-Temperature Operation below), it may be 
possible to operate the controller reliably at higher than 55û C with 
increased airflow. It is important to note that there are several 
factors, in addition to the rated CFM of the air mover, which 
determine the actual volume and speed of air flowing over the 
controller.
Special Considerations for Elevated-Temperature Operation
The following information is for users whose applications for the 
MVME162LX may subject it to high temperatures.