Intel 740, Руководство по конструкции, Страница: 149 / 246

Application Note 653
1
1.0 Introduction
In a system environment, the chipset temperature is a function of both the system and component
thermal characteristics. The system level thermal constraints consist of the local ambient
temperature at the component, the airflow over the component and surrounding board as well as the
physical constraints at, above, and surrounding the component. The component’s case temperature
depends on the component power dissipation, size, packaging materials (effective thermal
conductivity), the type of interconnection to the substrate and motherboard, the presence of a
thermal cooling solution, the thermal conductivity and the power density of the substrate, nearby
components, and motherboard.
All of these parameters are pushed by the continued trend of technology to increase performance
levels (higher operating speeds, MHz) and packaging density (more transistors). As operating
frequencies increase and packaging size decreases, the power density increases and the thermal
cooling solution space and airflow become more constrained. The result is an increased emphasis
on system design to ensure that thermal design requirements are met for each component in the
system.
1.1 Document Goals
The Intel740™ graphics accelerator is the newest addition to the growing market of fast, 3D
graphics accelerators. Previous generations of graphics accelerators generated insufficient heat to
require an enhanced cooling solution in order to meet the case temperature specifications in system
designs. As the market transition to higher-speeds with enhanced features, the heat generated by
these advanced graphics accelerators will introduce new thermal challenges for system designers.
Depending on the type of system and the chassis characteristics, new designs may be required to
provide better cooling solutions for these graphics accelerators. The goal of this document is to
provide an understanding of the thermal characteristics of the Intel740 graphics accelerator and
discuss guidelines for meeting the thermal requirements imposed on systems.
1.2 Importance of Thermal Management
The objective of thermal management is to ensure that the temperature of all components in a
system are maintained within functional limits. The functional temperature limit is the range within
which the electrical circuits can be expected to meet specified performance requirements.
Operation outside the functional limit can degrade system performance, cause logic errors or cause
component and/or system damage. Temperatures exceeding the maximum operating limits may
result in irreversible changes in the operating characteristics of the component.