82801DB Datasheet, PDF (57/587 Pages) Intel Corporation – Intel 82801DB I/O Controller Hub 4 (ICH4)

Intel^® ICH4 Power Planes and Pin States
Intel^® ICH4 Power Planes and
Pin States
3
3.1
This chapter describes the describes the system power planes for the ICH4. In addition, the ICH4
power planes and reset pin states for various signals are presented.
Power Planes
Table 3-1. Intel^® ICH4 System Power Planes
Plane
Main I/O
(3.3 V)
Description
Vcc3_3: Powered by the main power supply. When the system is in the S3, S4, S5, or
G3 state, this plane is assumed to be shut off.
Main Logic
(1.5 V)
Vcc1_5: Powered by the main power supply. When the system is in the S3, S4, S5, or
G3 state, this plane is assumed to be shut off.
Resume I/O
(3.3 V Standby)
VccSUS3_3: Powered by the main power supply in S0–S1 states. Powered by the
trickle power supply when the system is in the S3, S4, S5, state. Assumed to be shut off
only when in the G3 state (system is unplugged).
Resume Logic
(1.5 V Standby)
VccSUS1_5: Powered by the main power supply in S0–S1 states. Powered by the
trickle power supply when the system is in the S3, S4, S5, state. Assumed to be shut off
only when in the G3 state (system is unplugged).
CPU I/F
(0.8 ~ 1.75 V)
V_CPU_IO: Powered by the main power supply via CPU voltage regulator. When the
system is in the S3, S4, S5, or G3 state, this plane is assumed to be shut off.
Hub Interface Logic
(1.5 V or 1.8 V)
VccHI: Powered by the main power supply. Assumed to be 1.5 V when operating in
Hub Interface 1.5 mode and 1.8 V when operating in Hub Interface 1.0 mode. When the
system is in the S3, S4, S5, or G3 state, this plane is assumed to be shut off.
RTC
VccRTC: When other power is available (from the main supply), external diode
coupling will provide power to reduce the drain on the RTC battery. Assumed to operate
from 3.3 V down to 2.0 V.
Intel^® 82801DB ICH4 Datasheet
57