Intel Pentium 4 User Manual

I/O Controller Hub 2
R
152 Intel
®
Pentium
®
4 Processor / Intel
®
850 Chipset Family Platform Design Guide
9.6.1.3 The Unified VCC_ Suspend Architecture
In this design all SMBus devices are powered by the VCC_Suspend supply. Consideration must be
made to provide enough VCC_Suspend current while in STR.
Figure 106. Unified VCC_Suspend Architecture
ICH2
SM BUS
DEVICES
Vsus
SM BUS
Vsus
Vsus
9.6.1.4 The Unified VCC_Core Architecture
In this design, all SMBUS devices are powered by the VCC_Core supply. This architecture allows
none of the devices to operate in STR, but minimizes the load on VCC_Suspend. See Figure 107.
Figure 107. Unified VCC_Core Architecture
ICH2
SM BUS
DEVICES
Vsus
Vcore
SM BUS
Vcore
NOTES:
1. The SMBus device needs to be back-drive safe while its supply (Vcore) is off and VCC_Suspend is still
powered.
2. In suspended modes where VCC_Core is OFF and VCC_Suspend is on, the VCC_Core node will be
very near ground. In this case the input leakage of the ICH2 will be approximately 10 uA.

Intel Pentium 4 Specifications

General

Brand	Intel
Model	Pentium 4
Category	Computer Hardware
Language	English