Intel® Thermal/Mechanical Reference Design Information
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Thermal/Mechanical Design Guide
41
5.1.4
Reference Heatsink Thermal Validation
The Intel reference heatsink is validated within specific boundary conditions based on the
methodology described in Section 5.2.
Testing is done on bench top test boards at ambient lab temperature. In particular, for the
reference heatsink, the Plexiglas* barrier is installed 81.28 mm [3.2 in] above the motherboard
(refer to Sections 3.3 and 5.6).
The test results, for a number of samples, are reported in terms of a worst-case mean + 3
σ
value
for thermal characterization parameter using actual processors (based on the thermal test vehicle
correction factors).
Note:
The above 81.28 mm obstruction height that is used for testing complies with the recommended
obstruction height of 88.9 mm for the ATX form factor. However, it would not be sufficient for
systems in strict compliance with the ATX specification that defines a 76.2 mm obstruction height
in Area A.
5.1.5
Fan Performance for Active Heatsink Thermal Solution
The fan power requirements for proper operation are given in Table 3.
Table 3. Fan Electrical Performance Requirements
Requirement Value
Peak fan current draw
1.5 A
Average fan current draw
1.1 A
Fan start-up current draw
2.2 A
Fan start-up current draw maximum
duration
1.0 second
Fan header voltage
12 V ± 10%
Tachometer output
2 pulse per revolution
In addition to comply with overall thermal requirements (Section 5.1.1), and the general
environmental reliability requirements (Section 5.2) the fan should meet the following
performance requirements:
•
Mechanical wear out represents the highest risk reliability parameter for fans. The capability
of the functional mechanical elements (ball bearing, shaft, and tower assembly) must be
demonstrated to a minimum useful lifetime of 50,000 hours.
•
In addition to passing the environmental reliability tests described in Section 5.2, the fan
must demonstrate adequate performance after 7,500 on/off cycles with each cycle specified
as 3 minutes on, 2 minutes off, at a temperature of 70 °C.
See the
Fan Specification for 4-wire PWM Controlled Fans
for additional details on the fan
specification.
Summary of Contents for 640 - Pentium 4 640 3.2GHz 800MHz 2MB Socket 775 CPU
Page 14: ...Introduction R 14 Thermal Mechanical Design Guide ...
Page 38: ...Thermal Management Logic and Thermal Monitor Feature R 38 Thermal Mechanical Design Guide ...
Page 52: ...Intel Thermal Mechanical Reference Design Information R 52 Thermal Mechanical Design Guide ...
Page 60: ...Acoustic Fan Speed Control R 60 Thermal Mechanical Design Guide ...
Page 72: ...Heatsink Clip Load Metrology R 72 Thermal Mechanical Design Guide ...
Page 99: ...Mechanical Drawings R Thermal Mechanical Design Guide 99 Figure 50 Reference Fastener Sheet 1 ...
Page 103: ...Mechanical Drawings R Thermal Mechanical Design Guide 103 Figure 54 Clip Heatsink Assembly ...
