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AP-973 Application Note

Pentium® III Xeon Processor with 1MB and 2MB L2 Cache

AP-973 Application Note
Pentium® III Xeon Processor with 1MB and 2MB L2 Cache
Thermal Solutions Guidelines
Order number 245489-001 May, 2000
Table of Contents
INTRODUCTION....................................................... 4 TERMINOLOGY........................................................ 5 REFERENCES.......................................................... 6 REFERENCE THERMAL SOLUTION...................................... 7 4.1 Thermal Assumptions .................................................. 7 4.2 Thermal Analysis ...................................................... 8 4.3 Thermal Conclusion ................................................... 10 4.4 Pentium® III Xeon Processor with 1MB and 2MB L2 Cache Thermal Update ... 10 5. HEAT SINK SAMPLE INFORMATION .................................... 11 6. COMMON QUESTIONS ................................................ 12
INTRODUCTION
TERMINOLOGY
REFERENCES
The reader of this Application Note should also be familiar with material and concepts presented in the datasheets, applications notes, and other documents for the Pentium® III Xeon processor family. These are found at: http://developer.intel.com / design / pentiumiii / xeon /
REFERENCE THERMAL SOLUTION
The reference passive heat sink solution that was designed for the Pentium® III Xeon processors at 550 MHz can provide adequate cooling for the Pentium III Xeon processor at 700 MHz with 1MB and 2MB L2 cache (based on certain airflow and ambient temperature assumptions, described in greater detail in this document). See Chapter 5 for heat sink ordering information. 4.1 Thermal Assumptions
Thermal Analysis
Figure 1.
Thermal density areas of Pentium® III Xeon processor with 1MB and 2MB L2 cache core and OCVR components
Thermal Conclusion
The reference passive heat sink will keep the Pentium® III Xeon processor with 1MB and 2MB L2 cache thermal plate temperature at or below its specified value, if the local ambient temperature (TLA) is maintained at 40°C or less, with an airflow of at least 300 LFM.
4.4 Pentium® III Xeon Processor with 1MB and 2MB L2 Cache Thermal Update The Pentium® III Xeon processor with 1MB and 2MB L2 cache OLGA-2 Integrated Heat Spreader size is 1.516" X 1.516", as shown in Figure 1. The effective heat source size of the Pentium® III Xeon processor with 1MB and 2MB L2 cache with OLGA-2 Integrated Heat Spreader is two times that of the Pentium III Xeon processor with 256KB L2 cache core size (which uses the OLGA-1 package) of 0.448" X 0.362". The 2X factor has been determined by analytical and empirical data. The performance of the Pentium III Xeon processor at 550 MHz reference heat sink will improve significantly due to the heat source size increase with the package change from OLGA-1 on the Pentium III Xeon processors with 256KB L2 cache to the OLGA-2 package on the Pentium III Xeon processors with 1MB and 2MB L2 cache. Consequently, the heat sink thermal resistance (PA) will decrease. Without accounting for the reduction in PA, the present reference thermal heat sink solution satisfies the TPLATE requirement of 65°C for Pentium III Xeon processors with 1MB and 2MB L2 cache.
HEAT SINK SAMPLE INFORMATION
A passive heat sink is available from several vendors, including Thermalloy (part number 22730U-CP35). See Figure 2 below. For more mechanical information refer to Chapter 9 of the latest Pentium® III Xeon processor with 1MB and 2MB L2 cache datasheet (Order Number 248711). For heat sink assembly information contact your Intel representative or contact Thermalloy at:
Thermalloy, Inc. 2021 W. Valley View Lane Dallas, TX 75234 Tel (972) 488-4257 Fax (972) 488-4461 http://www.thermalloy.com /
CONCEPTUAL
Figure 2.
Reference passive heat sink
COMMON QUESTIONS