Intel 740, Design Manual

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Application Note 653
3
Intel740™ Graphics Accelerator Thermal Design Considerations
2.0 Thermal Specifications
The Intel740™ graphics accelerator power dissipation can be found in the Intel740™ Graphics
Accelerator Datasheet and Intel740™ Graphics Accelerator Specification Updates. Please refer to
these documents to verify the actual thermal specifications for the Intel740 graphics accelerator. In
general, systems should be designed to dissipate the highest possible thermal power.
To ensure proper operation and reliability of the Intel740 graphics accelerator, the thermal solution
must maintain the case temperature at or below its specified value (
Table 1 ). Considering the
power dissipation levels and typical system ambient environments of 45°C to 55°C, if the Intel740
graphics accelerator case temperature exceeds the maximum case temperature listed in
Table 1 ,
system or component level thermal enhancements will be required to dissipate the heat generated.
The thermal characterization data described in later sections illustrates that good system airflow is
critical. In typical systems the thermal solution is limited by board layout, spacing and component
placement. Airflow is determined by the size and number of fans and vents along with their
placement in relation to the components and the airflow channels within the system. In addition,
acoustic noise constraints may limit the size and/or types of fans and vents that can be used in a
particular design.
To develop a reliable, cost-effective thermal solution, all of the above variables must be
considered. Thermal characterization and simulation should be carried out at the entire system
level accounting for the thermal requirements of each component.
NOTES:
1. T
case-nhs
is defined as the maximum case temperature without a Heat Sink attached.
2. T
case-hs
is defined as the maximum case temperature with a Heat Sink attached (see Section 4.2, “Thermal
Enhancements” on page 10 ).
2.1 Case Temperature
The case temperature is a function of the local ambient temperature and the internal temperature of
the Intel740graphics accelerator. As a local ambient temperature is not specified for the Intel740,
the only restriction is that the maximum case temperature (T
case
) is not exceeded. Section 5.1,
“Case Temperature Measurements” on page 19 discusses proper guidelines for measuring the case
temperature.
Note: Increasing the heat flow through the case increases the difference in temperature between the
junction and case, reducing the maximum allowable case temperature.
Table 1. Intel740 Graphics Accelerator Preliminary Thermal Absolute Maximum Rating
Parameter Maximum
T
case-nhs
1 109°C
T
case-hs
2 96°C