Kontron AM4024e - Manual (Page 53)

D R A F T — F O R I N
T E R N A L U S E O N L Y
53 www.kontron.com
User Guide
AM4024(E)
5 Thermal Considerations
The thermal characteristic graphs shown in the following sections are intended to serve as guidance
for reconciling the required computing power with the necessary system volumetric airflow over the
ambient temperature. The graphs contain two curves representing upper level working points based on
different levels of average CPU utilization. When operating below the corresponding curve, the CPU
runs without any intervention of thermal supervision (the CPU is below 100°C). When operated above
the corresponding curve, various thermal protection mechanisms may take effect resulting in tempo-
rarily reduced CPU performance or finally in an emergency stop (the CPU is at 125°C) in order to protect
the CPU and the chipset from thermal destruction. In real applications this means that the board can
be operated temporarily at a higher ambient temperature or at a reduced flow rate and still provide
some margin for temporarily requested peak performance before thermal protection will be activated.
An airflow of 20 cfm is a typical value for a standard Kontron MicroTCA system. For other systems the
available airflow will differ. The maximum ambient operating temperature must be determined for such
environments.
How to read the diagram
Select a specific CPU and choose a specific working point. For a given flow rate there is a maximum air-
flow input temperature (= ambient temperature) provided. Below this operating point, thermal super-
vision will not be activated. Above this operating point, thermal supervision will become active
protecting the CPU from thermal destruction. The minimum flow rate provided must be more than the
value specified in the diagram.
Volumetric flow rate
The volumetric flow rate refers to an airflow through a fixed cross-sectional area (i.e. slot width x
depth. The volumetric flow rate is specified in m³/s (cubic-meter-per-second) or cfm (cubic-feet-per-
minute) respectively.
Conversion:
1 cfm = 0.47 x 10
- ³ m ³ /s = 1.7 m ³ /h
1 m ³ /s = 3600 m ³ /h = 2118.9 cfm
The following figures illustrate the operational limits of the AM4024(E) taking into consideration pow-
er consumption vs. ambient air temperature vs. airflow rate. The maximum airflow input temperature
was measured at the bottom of the AMC module just before the air flowed over the board.
Note: The AM4024(E) must be operated within the thermal operational limits indicated below.