Vsb; Power Summary; Processor Power Distribution Guidelines; Processor Power Requirements - Intel Xeon Design Manual

Platform Power Delivery Guidelines
12.1.7

3.3 VSB

The 3.3 VSB power plane is the output of a 5 VSB-to-3.3 VSB voltage regulator. The power plane
is used solely for the resume I/O features of the ICH3-S. This segment is given only about 64 mA.
This regulator is required in all designs.
12.1.8 1.8 VSB
As stated before, the 1.8 VSB provides power to the resume logic within the ICH3-S. This logic
uses about 14.01 mA. This regulator is required in all designs.
12.1.9

Power Summary

The following table summarizes the platform power.
Table 12-1. Power Summary
Power Rail
CPU
2.5 V
1.25 V
1.8 V
1.2 V
5 VSB
3.3 VSB
1.8 VSB
12.2

Processor Power Distribution Guidelines

12.2.1

Processor Power Requirements

This section describes the requirements for supplying power to a Intel Xeon processor. For detailed
electrical specifications, refer to the Intel
2 GHz, and 2.20 GHz Datasheet. The processor will typically operate between VCC_MID and
VCC_MAX. The processor allows the use of Auto HALT, Stop-Grant, Sleep, and Deep Sleep
states to reduce power consumption by stopping the clock to specific internal sections of the
processor and the BCLK depending on each particular state. This can create load-change transients
as high as 450 amps per microsecond on VCC_CPU at the socket pins. Note that the processor can
also cause load changes of this magnitude while executing regular code. In this document, a load-
change transient is a change from one current requirement (averaged over many clocks) to another.
In the future, the processor may require higher currents and different voltages.
12.2.1.1

Multiple Voltages

"VCC_CPU" in this section refers to the processor core VCC, cache supply voltage, and Assisted
Gunning Transceiver Logic + (AGTL+) supply voltage. In the processor, the core and cache are on
the same silicon and are powered from the same power plane–unlike Pentium II Xeon and
Pentium III Xeon processors, which required different power planes.
162
Source
VRM 9.1 / VRD
5 V switching regulator
5 V to 2.5 V switching regulator
5 V switching regulator
1.8 V switching regulator
Power Supply
5 VSB voltage regulator
5 VSB voltage regulator
®
Destination
®
2 CPUs, MCH, Intel ICH3-S
MCH DDR
MCH DDR
P64H2, ICH3-S
MCH
3.3 VSB, 1.8 VSB
ICH3-S
ICH3-S
Xeon™ Processor with 512 KB L2 Cache at 1.80 GHz,
Max Current
126 A
26 A
12.5 A
13.86 A
3.1 A
78 mA
64 mA
14.01 mA
Design Guide