Guide

Intel

Celeron

D Processor for Embedded Applications Thermal Design Guide 25

Characterizing Cooling Performance Requirements

If the local processor ambient temperature is assumed to be 40° C, the same calculation may be

performed to determine the new case-to-ambient thermal resistance:

It is evident from the above calculations that a reduction in the local processor ambient temperature

has a significant positive effect on the case-to-ambient thermal resistance requirement.

3.2 Looking at the Whole Thermal Solution

The heat generated by components within the chassis must be removed to provide an adequate

operating environment for both the processor and other system components. Moving air through

the chassis brings in air from the external ambient environment and transports the heat generated

by the processor and other system components out of the system. The number, size and relative

position of fans and vents have a decisive impact on the chassis thermal performance, and therefore

on the ambient temperature around the processor. The size and type (passive or active) of the

thermal cooling device and the amount of system airflow are related and may be traded off against

each other to meet specific system design constraints. Additional constraints are board layout,

spacing, component placement, and structural considerations that limit the thermal solution size.

For more information, refer to the Performance ATX Desktop System Thermal Design Suggestions

or Performance microATX Desktop System Thermal Design Suggestions available at

http://www.formfactors.org/. For more information on server standards, visit the Server System

Infrastructure web site at http://www.ssiforum.org/.

In addition to passive heatsinks, fan heatsinks and system fans, other solutions exist for cooling

integrated circuit devices. For example, ducted blowers, heat pipes and liquid cooling are all

capable of dissipating additional heat. Due to their varying attributes, each of these solutions may

be appropriate for a particular system implementation.

To develop a reliable, cost-effective thermal solution, thermal characterization and simulation shall

be carried out at the entire system level, accounting for the thermal requirements of each

component. In addition, acoustic noise constraints may limit the size, number, placement, and types

of fans that may be used in a particular design.

To ease the burden on cooling solutions, the Intel Thermal Monitor feature and associated logic

have been integrated into the silicon of the Intel Celeron D Processor. By taking advantage of the

Intel Thermal Monitor, system designers may reduce cooling system cost while maintaining

processor reliability and performance goals. For more information about the Intel Thermal

Monitor, refer to the Intel Celeron D Datasheet.

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