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5.2.1.2.2
Post-Test Pass Criteria
The post-test pass criteria are:
1. No significant physical damage to the pump assembly attach mechanism
(including such items as clip and motherboard fasteners).
2. The assembly must remain attached to the motherboard.
3. The assembly remains seated and its bottom remains mated flatly against IHS
surface. No visible gap between the heatsink base and processor IHS. No visible
tilt of the heatsink with respect to its attach mechanism.
4. No signs of physical damage on motherboard surface due to impact of the
assembly or its attach mechanism.
5. No visible physical damage to the processor package.
6. Successful BIOS/Processor/memory test of post-test samples.
7. Thermal compliance testing to demonstrate that the case temperature
specification can be met.
5.2.2
Power Cycling
Thermal performance degradation due to TIM degradation is evaluated using power
cycling testing. The test is defined by 7500 cycles for the case temperature from room
temperature (~23 ºC) to the maximum case temperature defined by the thermal
profile at TDP. Thermal Test Vehicle (refer to Section Error! Reference source not
found.) is used for this test.
5.2.3
Reliability Testing
The ALCT solution is a complex assembly with multiple joints and injection molded
plastic parts. The selection of materials for pump and tubing as well as joint designs
are done to provide a liquid-tight environment and to minimize the loss of liquid to
ambient through vapor transmission. A reservoir is included in the heat exchanger to
mitigate the impact of the vapor transmission loss. The design approach that is used
for the selection of tubing and for reservoir sizing based on reliability testing is shown
in Table 6. The results of the reliability testing and their impact on thermal resistance
pump motor performance and on pump integrity are summarized.
The complex assembly of ALCT and the sensitivity of reliability to manufacturing
environment would require frequent verification of parts for reliability. The objective of
the reliability testing of the design is to identify key failure mechanisms and to
develop design paths to mitigate them under a reasonable set of use conditions. The
reliability testing and results are not expected to represent the performance of the
design and may require additional testing to verify the performance in a particular use
condition environment.
46
LGA775 Socket Heatsink Loading
Thermal and Mechanical Design Guidelines
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