Intel 810A3, Design Manual

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Intel
®
810A3 Chipset Design Guide 2-13
PGA370 Processor Design Guidelines
2.2.10.2 Vtt Decoupling Design
For Itt = 3.0 A (max).
•
Nineteen - 0.1 uF capacitors in 0603 packages placed within 200 mils of AGTL+ termination
R-pack’s, one capacitor for every two R-packs. These capacitors are shown on the outer
exterior of
Figure 2-6 . These are located on the motherboard.
Vref Decoup
l
ing Design
•
Four - 0.1uF capacitors in 0603 package placed near V
REF
pins (within 500 mils).
2.2.11 Thermal/EMI Differences
Heatsink requirements will be different for FC-PGA processors from previous processors using
PPGA packaging. Refer to the processor datasheet for specific guidelines.
•
Increased power density for Intel
®
Pentium
®
III processor (approximately 27 W/cm
2
).
•
Different thermal design verification for FC-PGA compared to PPGA packaged processors.
Intel
®
Pentium
®
III processors are specified using Tjunction versus Tcase (used with Intel
®
Celeron

processors).
•
New heatsink for FC-PGA package which is not backwards compatible with PPGA
processors.
•
New heatsink clips for FC-PGA processor heatsinks.