Intel Xeon Processor and Intel E7500/E7501Chipset Compatible Platform Design Guide

Intel
®
Xeon™ Processor and Intel
®
E7500/E7501 Chipset Compatible Platform Design Guide 175
Platform Power Delivery Guidelines
11.1.6 1.2 V
The 1.2 V power plane powers the MCH core logic requiring 4.5 A. A switching regulator using
either the 3.3 V or the 5 V power rail is the regulator’s input to power the 1.2V plane.
11.1.7 5 VSB
The 5 VSB power plane comes directly off the 5 VSB power rail and has two functions, to provide
power to resume functions via a 3.3 VSB regulator in I/O devices off of the ICH3-S, and to provide
1.8 VSB power through a linear regulator. The resume I/O segment of the ICH3-S requires 64 mA
of current, while the 5 VSB-to-1.8 VSB regulator requires 14.01 mA.
11.1.8 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.
11.1.9 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 mA. This regulator is required in all designs.
11.1.10 Power Summary
Table 11-1 summarizes the platform power. For current, up to date values, refer to each
component’s datasheet.
Table 11-1. Power Summary
Power Rail Source Destination Max Current
Processor VRM 9.1 / VRD 2 Processors, MCH, Intel
®
ICH3-S 140 A
2.5 V 12 V switching regulator MCH DDR 27 A
1.25 V 5 V to 2.5 V switching regulator MCH DDR 12.5 A
1.8 V 12 V switching regulator Intel
®
P64H2, 1.2 V switching regulator 8.42 A
1.8 V 3.3 V linear regulator ICH3-S 550 mA
1.2 V 12 V switching regulator MCH 4.5 A
5 VSB Power Supply 3.3 VSB, 1.8 VSB 78 mA
3.3 VSB 5 VSB voltage regulator ICH3-S 64 mA
1.8 VSB 5 VSB voltage regulator ICH3-S 14 mA