Intel Xeon X3440 BX80605X3440 User Manual

Product codes
BX80605X3440
Page of 106
Thermal/Mechanical Specifications and Design Guidelines
57
Sensor Based Thermal Specification Design Guidance
7.3.1
Boundary Condition Definition
Using the knowledge of the system boundary conditions such as inlet air temperature, 
acoustic requirements, cost, design for manufacturing, package and socket mechanical 
specifications and chassis environmental test limits the designer can make informed 
thermal solution design decisions.
For the Intel
® 
Xeon
®
 processor 3400 series (95W), the thermal boundary conditions 
for a 1U Server system are as follows:
• T
EXTERNAL
 = 35 °C. This is typical of a maximum system operating environment
• T
RISE
 = 5 °C
• T
AMBIENT
 = 40 °C (T
AMBIENT
 = T
EXTERNAL
 + T
RISE
)
Based on the system boundary conditions the designer can select a T
AMBIENT
 and Ψ
CA
 to 
use in thermal modelling. The assumption of a T
AMBIENT
 has a significant impact on the 
required Ψ
CA
 needed to meet TTV T
CASEMAX 
at TDP. A system that can deliver lower 
assumed T
AMBIENT
 can utilize a design with a higher Ψ
CA
, which can have a lower cost. 
 shows a number of satisfactory solutions for the Intel
® 
Xeon
®
 processor 
3400 series (95W). 
Note:
If the assumed T
AMBIENT
 is inappropriate for the intended system environment, the 
thermal solution performance may not be sufficient to meet the product requirements. 
The results may be excessive noise from fans having to operate at a speed higher than 
intended. In the worst case this can lead to performance loss with excessive activation 
of the Thermal Control Circuit (TCC).
Note:
If an ambient of greater than 45.1 °C is necessary based on the boundary conditions a 
thermal solution with a Ψ
CA
 lower than 0.29 °C/W will be required.
Figure 7-3. Required Ψ
CA
 for Various T
AMBIENT
 Conditions
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
0
20
40
60
80
TTV Power Dissipation (W)
T
T
V
 T
c
ase (
°C
)
Ψ-ca = 0.45 
Ta = 30 °C 
Ψ-ca = 0.40 
Ta = 35 °C 
Ψ-ca = 0.34 
Ta = 40 °C 
Ψ-ca = 0.29 
Ta = 45.1 °C