Intel Pentium 4 Processor with 512-KB L2 Cache on 0.13 Micron Process Thermal Design Guidelines

Conclusion
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5 Conclusion
As the complexities of today’s microprocessors increase, the power dissipation requirements
become more exacting. Care must be taken to ensure that the additional power is properly
dissipated. Heat can be dissipated using passive heatsinks, fans and/or active cooling devices.
Incorporating ducted airflow solutions into the system thermal design can yield additional margin.
The Pentium 4 processor with 512-KB L2 cache on 0.13 micron process has thermal management
logic integrated into the processor silicon. Their circuits may be configured to automatically
control the processor temperature through the use of the Thermal Monitor feature. In the event it
reaches a factory-calibrated temperature, the processor periodically stops the internal clocks in
order to reduce power consumption and allow the processor to cool down and stay within thermal
specifications. Various registers and bus signals are available to monitor and control the processor
thermal status. A cooling solution designed to the thermal design power (TDP) as specified in the
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adequately cool the processor to a level where activation of the Thermal Monitor feature is either
very rare or non-existent. Various levels of performance versus cooling capacity are available and
must be understood before designing a chassis. Automatic thermal management must be used as
part of the total system thermal solution.
The size and type of the heatsink, as well as the output of the fan can be varied to balance size,
cost, and space constraints with acoustic noise. This document has presented the conditions and
requirements for designing a heatsink solution for a system based on a Pentium 4 processor with
512-KB L2 cache on 0.13 micron process. Properly designed solutions provide adequate cooling
to maintain the processor thermal specification. This is accomplished by providing a low local
ambient temperature and creating a solution with a minimal thermal characterization parameter to
that local ambient temperature. Fan heatsinks or ducting can be used to cool the processor if
proper package temperatures cannot be maintained otherwise. By maintaining the processor case
temperature at the values specified in the processor datasheet, a system designer can be confident
of proper functionality and reliability of these processors.