Intel
®
Pentium
®
III Processor with 512KB L2 Cache Dual Processor Platform Design Guide
5-1
Power
5
The intent of this section is to familiarize the reader with the processor power requirements for an Intel
®
Pentium
®
III Processor with 512KB L2 Cache dual processor platform, and to show simulation model
and power implementation techniques. Only specific power distribution and control issues pertaining to
Intel
®
Pentium
®
III Processor with 512KB L2 Cache platforms are discussed in this section. It is assumed
that the reader is familiar with power distribution issues of the Intel
®
Pentium
®
III processors.
5.1
Terminology
“Power-Good” or “PWRGOOD” (an active high signal) indicates that all of the supplies and clocks
within the system are stable. PWRGOOD should go active a predetermined time after system voltages
are stable and should go inactive as soon as any of these voltages fail their specifications.
“V
CC
” or “Vcc
CORE
” refers to Intel
®
Pentium
®
III Processor with 512KB L2 Cache core and cache
supply voltages.
“V
TT
” refers to the AGTL termination voltage.
“AGTL” refers to Intel
®
Pentium
®
III Processor with 512KB L2 Cache’s Assisted Gunning Transceiver
Logic supply voltage. “AGTL” is the bus between the processor and its chipset. The terms “AGTL” and
“System Bus” are synonymous.
“VRM 8.5” refers to the DC-DC design guidelines for Intel
®
Pentium
®
III Processors with 512KB L2
Cache. These voltage regulator design supplies the required voltage and current to a single processor.
5.2
Typical Power Delivery
Power distribution is generally thought of as supplying power to the components that require it. Most
digital designers typically assume that an ideal supply will be provided. The printed circuit board (PCB)
designers attempt to create this ideal supply with two power planes in the PCB or by using large width
traces to distribute power. High frequency noise created when logic gates switch is typically controlled
with high frequency ceramic capacitors, which are recharged from lower frequency bulk capacitors.
Various rule of thumb methods exist for determining the amount of each type of capacitance that is
