82598EB Datasheet, PDF (588/596 Pages) Intel Corporation – Intel® 82598EB 10 Gigabit Ethernet Controller Datasheet

Intel^® 82598EB 10 GbE Controller - Thermal Enhancements
Extruded Aluminum Heat Sink
Figure 8-13. Extruded Heatsinks
8.16.5.3.1 Attaching the Extruded Heatsink
ECB-00181-01-GP Fansink
The extruded heatsink may be attached using clips with a phase change thermal interface material.
8.16.5.3.1.1 Clips
A well-designed clip, in conjunction with a thermal interface material (tape, grease, etc.) often offers
the best combination of mechanical stability. Use of a clip requires significant advance planning as
mounting holes are required in the PCB. Use non-plated mounting with a grounded annular ring on the
solder side of the board surrounding the hole. For a typical low-cost clip, set the annular ring inner
diameter to 150 mils and an outer diameter to 300 mils. Define the ring to have at least eight ground
connections. Set the solder mask opening for these holes with a radius of 300 mils.
8.16.5.3.1.2 Thermal Interface (PCM45 Series)
The PCM45 series from Honeywell* is recommended. These thermal interface pads are phase change
materials formulated for use in high performance devices requiring minimum thermal resistance. They
consist of an electrically non-conductive, dry film that softens at device operating temperatures
resulting in greasy-like performance.
Each PCA, system and heatsink combination varies in attach strength. Carefully evaluate the reliability
of tape attaches prior to high-volume use.
8.16.5.4 Thermal Considerations for Board Design
The following PCB design guidelines are recommended to maximize the thermal performance of FCBGA
packages:
• When connecting ground (thermal) vias to the ground planes, do not use thermal-relief patterns.
• Thermal-relief patterns are designed to limit heat transfer between the vias and the copper
planes, thus constricting the heat flow path from the component to the ground planes in the PCB.
• As board temperature also has an effect on the thermal performance of the package, avoid
placing the 82598 adjacent to high-power dissipation devices.
• If airflow exists, locate the components in the mainstream of the airflow path for maximum
thermal performance.
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