Cooling Requirements
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Special Considerations for Elevated-Temperature Operation
The following information is for users whose applications for the
MVME172P4 may subject it to high temperatures.
The MVME172P4 uses commercial-grade devices. Therefore, it can
operate in an environment with ambient air temperatures from 0° C to 70°
C. Several factors influence the ambient temperature seen by components
on the MVME172P4. Among them are inlet air temperature; air flow
characteristics; number, types, and locations of IP modules; power
dissipation of adjacent boards in the system, etc.
A temperature profile of the MVME172P4 (MVME172P-6xx) was
developed in an MVME945 12-slot VME chassis. This board was loaded
with one GreenSpring IP-Dual P/T module (position A) and three
GreenSpring IP-488 modules (positions B, C, and D). One 25W load board
was installed adjacent to each side of the board under test. The exit air
velocity was approximately 200 LFM between the MVME172P4 and the
IP-Dual P/T module. Under these conditions, a 10° C rise between the inlet
and exit air was observed. At 70° C exit air temperature (60° C inlet air),
the junction temperatures of devices on the MVME172P4 were calculated
(from the measured case temperatures) and did not exceed 100° C.
!
Caution
For elevated-temperature operation, perform similar measurements and
calculations to determine the actual operating margin for your specific
environment.
To facilitate elevated-temperature operation:
1. Position the MVME172P4 in the chassis to allow for maximum
airflow over the component side of the board.
2. Do not place boards with high power dissipation next to the
MVME172P4.
3. Use low-power IP modules only. The preferred locations for IP
modules are position A (J4 and J5) and position D (J29 and J30).
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