January 2007
101
Intel
®
855GME Chipset and Intel
®
6300ESB ICH Embedded Platform Design Guide
4.4.5
GMCH Core Voltage Plane and Decoupling
The VCC-GMCH (1.35 V) plane feeds the internal core logic of the 82855GME. VCC-GMCH
does not employ on-package decoupling. To ensure accurate VCC-GMCH voltage on the GMCH
die, follow the decoupling guidelines listed in
. The component form factors,
layout style, and decoupling capacitor values must be used with no deviation.
4.5
Power and Sleep State Definitions
Suspend-To-RAM (STR): In the STR state, the system state is stored in main memory and all
unnecessary system logic is turned off. Only main memory and logic
required to wake the system remain powered.
Full-power operation:
During full-power operation, all components on the motherboard remain
powered. Full-power operation includes both the full-on operating state
and the S1 (PROCESSOR stop-grant state) state.
Suspend operation:
During suspend operation; power is removed from some components on
the motherboard. The customer reference board supports three suspend
states: Suspend-to-RAM (S3), Suspend-to- Disk (S4), and Soft-off (S5).
Power rails:
An ATX power supply has 6 power rails: +5 V, -5 V, +12 V, -12 V,
+3.3 V, 5 Vsb. In addition to these power rails, several other power rails
are created with voltage regulators.
Core power rail:
Power rail that is only on during full-power operation. These power rails
are on when the PSON signal is asserted to the ATX power supply. The
core power rails that are distributed directly from the ATX 12 V power
supply are +5 V, -5 V, +12 V, -12 V, +3.3 V.
Standby power rail:
A power rail that is on during suspend operation (these rails are also on
during full-power operation). These rails are on at all times (when the
power supply is plugged into AC power). The only standby power rail
that is distributed directly from the ATX power supply is: 5 Vsb
(5 V Standby). There are other standby rails that are created with voltage
regulators on the motherboard.
Derived power rail:
A derived power rail is any power rail generated from another power rail
using an onboard voltage regulator. For example, 3.3 Vsb is usually
derived (on the motherboard) from 5 Vsb using a voltage regulator.
Dual power rail:
A dual power rail is derived from different rails at different times
(depending on the power state of the system). Usually, a dual power rail
is derived from a standby supply during suspend operation and derived
from a core supply during full-power operation.
Note: The voltage on a dual power rail may be misleading.
Table 22. Intel
®
Pentium
®
M/Celeron
®
M Processor V
CCP
Decoupling Guidelines
Description
Cap ESR ESL
Notes
Low-Frequency Decoupling (Polymer-Covered
Tantalum – POSCAP, Neocap, KO Cap)
2 x 150 µF
42 m
Ω
(typ)/2
2.5 nH/2
High-Frequency Decoupling (0603 MLCC, >= X7R)
Place next to the CPU
10 x 0.1 µF
16 m
Ω
(typ)/10
0.6 nH/10
Summary of Contents for 6300ESB ICH
Page 24: ...24 Intel 855GME Chipset and Intel 6300ESB ICH Embedded Platform Design Guide Introduction...
Page 102: ...102 Intel 855GME Chipset and Intel 6300ESB ICH Embedded Platform Design Guide...
Page 122: ...122 Intel 855GME Chipset and Intel 6300ESB ICH Embedded Platform Design Guide...
Page 190: ...190 Intel 855GME Chipset and Intel 6300ESB ICH Embedded Platform Design Guide Hub Interface...
Page 318: ...318 Intel 855GME Chipset and Intel 6300ESB ICH Embedded Platform Design Guide Layout Checklist...
