Intel Pentium 4 Processor in the 478-Pin Package Thermal Design Guidelines

Intel

Pentium

4 Processor in the 478-Pin Package Thermal Design Guidelines

50 Design Guide

3.3.3 Reference Heatsink Attach Clip Information

Guidelines for heatsink attach clip are given section 2.1.2. More specifically, the reference

heatsink clip for the Intel

Pentium

4 processor in the 478-pin package is latched to the retention

tab features at each corner of the retention mechanism (see reference retention mechanism tab

features and reference clip design details in Appendix B).

The reference heatsink attach clip is designed to support the reference heatsink, or heatsinks

designed according to the guidelines given section 3.3.2 above.

Intel’s target load applied by the clips to the processor heat spreader is 75 ±15 lbf (maximum load

is constrained by the package load capability, described in the processor datasheet). It is normal to

observe a bow or bend in the board due to this compressive load on the processor package and the

socket. The level of bow or bend depends on the motherboard material properties and component

layout. Any additional board stiffening devices (like plates) are not necessary and should not be

used along with the reference mechanical components. Using such devices increases the

compressive load on the processor package and socket, likely beyond the maximum load that is

specified for those components.

Chassis that have adequate clearance between the motherboard and chassis wall (minimum 0.250

inch) should be selected to ensure the board's underside bend does not contact the chassis.

For additional information on the Intel reference mechanical design for the Intel Pentium 4

processor in the 478-pin package, refer to Mechanical Enabling for the Intel

Pentium

Processor in the 478-Pin Package document.

3.3.4 Thermal Interface Material

The Intel reference design uses a phase change material, T454 from Chomerics*, as the thermal

interface material.

For information on the benefit of the compressive load on the thermal interface material, refer to

the Mechanical Enabling for the Intel

Pentium

4 Processor in the 478-Pin Package document.

3.3.5 Intel Reference Mechanical Solution Component Drawings

The drawings for the mechanical components of the Intel Reference cooling solution for the Intel

Pentium 4 processor in the 478-pin package are given in Appendix B. These mechanical

components are meant to interface with the Intel reference fan heatsink (radial bent fin active

heatsink), or any solution that complies with the mechanical guidelines given in Sections 3.3.2 and

3.3.3. Ask your Intel sales representative for additional information.

For Intel enabled vendor information for the Intel Pentium 4 processor in the 478-pin package

thermal mechanical support components, refer to the following website:

http://developer.intel.com/design/Pentium4/components/478pin.htm