Motorola MVME2400 manual Cooling Requirements

Specifications

Table B-1. MVME240x Specifications (Continued)

Characteristics		Specifications
Asynchronous serial	PC16550
debug port
	Front panel I/O through RJ45 connector
Front panel:switches and	Reset and Abort switches
status indicators
	Four LEDs: BFL, CPU, PMC (one for PMC slot 2, one for slot 1)
Note The power requirement listed for the MVME240x does not
	include the power requirements for the PMC slots. The PMC
	specification allows for 7.5 watts per PMC slot. The 15 watts
	total can be drawn from any combination of the four voltage
	sources provided by the MVME240x: +3.3V, +5V, +12V,
	and -12V.

B

Cooling Requirements

The MVME240x VME processor Module is specified, designed, and tested to operate reliably with an incoming air temperature range from 0° to 55° C (32° to 131° F) with forced air cooling of the entire assembly (base board and modules) at a velocity typically achievable by using a 100 CFM axial fan. Temperature qualification is performed in a standard Motorola VMEsystem chassis. Twenty-five-watt load boards are inserted in two card slots, one on each side, 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 module under test. Test software is executed as the module is subjected to ambient temperature variations. Case temperatures of critical, high power density integrated circuits are monitored to ensure component vendors’ 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 module. Less airflow is required to cool the

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