Kontron CP308 User Manual page 118

Thermal Considerations
TDP curves
• 100% TDP curve
This load complies with the maximum thermal design power (TDP) indicated in Chap-
ter 5.2 Power Consumption, Table 5-8. 100% TDP can be achieved through the use
of specific tools to heat up the processor, but 100% TDP is unlikely to be reached in
real applications.
• 75% TDP curve
This load represents a "typical" maximum power consumption reached under OS con-
trolled applications. Typically, this load corresponds with 75% of the TDP (see Chapter
5.2 Power Consumption, Table 5-7).
How to read the diagram
Select a specific CPU and choose a specific working point indicated in TDP percentage. For a
given flow rate there is a maximum airflow input temperature (= ambient temperature) provided.
Below this operating point, thermal supervision will not be activated. Above this operating point,
thermal supervision will become active protecting the CPU from thermal destruction. The min-
imum airflow rate provided must not be less 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/h (cubic-meter-per-hour) or cfm (cubic-feet-
per-minute) respectively.
Conversion: 1 cfm = 1.7 m³/h; 1 m³/h = 0.59 cfm
Airflow
At a given cross-sectional area and a required flow rate, an average, homogeneous airflow
speed can be calculated using the following formula:
Airflow = Volumetric flow rate / area.
The airflow is specified in m/s (meter-per-second) or in fps (feet-per-second) respectively.
Conversion: 1 fps = 0.3048 m/s; 1 m/s = 3.28 fps
The following figures illustrate the operational limits of the CP308 taking into consideration
power consumption vs. ambient air temperature vs. airflow rate. The measurements were
made based on a 4HP slot and with both processor cores enabled.
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CP308
ID 1027-4487, Rev. 3.0