
Intel
®
Core
TM
2 Duo E6400, E4300, and Intel
®
Pentium
®
Dual-Core E2160 Processor—Thermal
Metrology
Intel
®
Core
TM
2 Duo E6400, E4300, and Intel
®
Pentium
®
Dual-Core E2160 Processor
TDG
October 2007
22
Order Number: 315279 - 003US
Ψ
SA
is a measure of the thermal characterization parameter from the bottom of the
heatsink to the local ambient air. SA is dependent on the heatsink material, thermal
conductivity, and geometry. It is also strongly dependent on the air velocity through
the fins of the heatsink.
Figure 4
illustrates the combination of the different thermal characterization
parameters.
3.1.1
Example
The cooling performance,
Ψ
CA
, is then defined using the principle of thermal
characterization parameter described above:
• The case temperature T
C-MAX
and thermal design power TDP given in the processor
datasheet.
• Define a target local ambient temperature at the processor, T
A
.
Since the processor thermal profile applies to all processor frequencies, it is important
to identify the worst case (lowest
Ψ
CA
) for a targeted chassis characterized by TA to
establish a design strategy.
The following provides an illustration of how one might determine the appropriate
performance targets. The example power and temperature numbers used here are not
related to any specific Intel processor thermal specifications, and are for illustration
purposes only.
Assume the TDP, as listed in the datasheet, is 100 W and the maximum case
temperature from the thermal profile for 100 W is 67° C. Assume as well that the
system airflow has been designed such that the local ambient temperature is 38° C.
Then the following could be calculated using
Equation 1
from above:
Ψ
CA
= (T
C
,- T
A
) / TDP = (67 - 38) / 100 = 0.29 °C/W
Figure 4.
Processor Thermal Characterization Parameter Relationships
TIM
T
S
T
A
Ψ
CA
LGA775 Socket
Processor
IHS
System Board
T
C
Heatsink
TIM
T
S
T
A
Ψ
CA
LGA775 Socket
Processor
IHS
System Board
T
C
Heatsink