Guidelines

Intel
®
7500 Chipset Thermal Mechanical Design Guide 39
Reference Thermal Solution 2
represents the TIM performance post heatsink assembly while the End of Life value is
the predicted TIM performance when the product and TIM reaches the end of its life.
The heatsink clip provides enough pressure for the TIM to achieve End of Line thermal
resistance of 0.19°C cm
2
/W and End of Life thermal resistance of 0.39°C cm
2
/W.
7.5.5 Heatsink Clip
The reference solution uses a wire clip with hooked ends. The hooks attach to wire
anchors to fasten the clip to the board. See Appendix B for a drawing of the clip. Refer
to Table 6-3 for “Target Heatsink Clip Design Load.”
7.5.6 Clip Retention Anchors
For Intel 7500 chipset-based platforms that have very limited board space, a clip
retention anchor has been developed to minimize the impact of clip retention on the
board. It is based on a standard three-pin jumper and is soldered to the board like any
common through-hole header. A new anchor design is available with 45° bent leads to
increase the anchor attach reliability over time. See Section 6.5.6 for more details. Part
number and supplier information are provided in Appendix A.
7.6 Reliability Guidelines
Each motherboard, heatsink and attach combination may vary the mechanical loading
to the component. Based on the end user environment, the user should define the
appropriate reliability test criteria and carefully evaluate the completed assembly prior
to use in high volume. The reference solution is to be mounted to a fully configured
system. The environmental reliability requirements for the reference thermal solution
are shown in Table 7-3 These could be considered as general guidelines.
Notes:
1. It is recommended that the above tests be performed on a sample size of at least twelve assemblies from
three lots of material.
2. Additional inspection guidelines may be added at the discretion of the user.
§
Table 7-2. Honeywell PCM45 F* TIM Performance as a Function of Attach Pressure
Pressure on Thermal Solution
and Package Interface (PSI)
Thermal Resistance (°C × cm
2
)/W
End of Line End of Life
40 0.19 0.39
Table 7-3. Reliability Guidelines
Test
[1]
Objective Inspection Guidelines
[2]
Mechanical Shock System level unpackaged
Profile: 25G
2 drops in all 6 orientations
Visual Check and Electrical Functional
Test
Random Vibration System level unpackaged
Duration: 10 min/axis, 3 axes
Power Spectral Density Profile: 2.20g RMS
Visual Check and Electrical Functional
Test
Thermal Cycling -40°C to 85°C, in conformance to JEDEC Visual Check and Electrical Functional
Test