Schematic Checklist
202
Design Guide
RTC
VBIAS
•
The VBIAS pin of the ICH3-S is connected
to a 0.047 µF capacitor.
•
For noise immunity on VBIAS
signal.
•
Refer to
RTCX1
RTCX2
•
Connect a 32.768 kHz Crystal Oscillator
across these pins with a 10 M
Ω
resistor.
Decouple each signal using a 18 pF
capacitor.
•
RTCX1 may optionally be driven by an
external oscillator instead of a crystal.
These signals are 1.8 V only, and must not
be driven by a 3.3 V source.
•
The external circuitry shown in
is required to
maintain the accuracy of the
RTC.
•
Refer to
•
The circuitry is required
because the new RTC oscillator
is sensitive to step voltage
changes in VCCRTC and
VBIAS. A negative step on the
power supply of more than
100 mV will temporarily shut off
the oscillator for hundreds of
milliseconds.
•
Refer to
for
decoupling requirements.
System Management
SMBDATA
SMBCLK
•
Require external pull-up resistors. See
SMBus Architecture and Design
Consideration section to determine the
appropriate power well to use to tie the pull-
up resistors (core well, suspend well, or a
combination).
•
Pull-up value also determined by bus
section characteristics. Additional circuitry
may be required to connect high and low
powered sections.
•
SMBCLK required to be tied to SMLink0 and
SMBDATA required to be tied to SMLink1
for SMBus 2.0 compliance.
•
Value of pull-up resistors
determined by line load. Typical
value used is
8.2 k
Ω
± 5%
.
•
Refer to
SMBALERT#/
GPIO[11]
•
See GPIO section if SMBALERT# not
implemented.
SMLINK[1:0]
•
Requires external pull-up resistors. See
SMBus Architecture and Design
Consideration section to determine the
appropriate power well to use to tie the pull-
up resistors. (Core well, suspend well, or a
combination.)
•
Pull-up value also determined by bus
section characteristics. Additional circuitry
may be required to connect high and low
powered sections.
•
SMLink0 required to be tied to SMBCLK and
SMLink1 required to be tied to SMBDATA
for SMBus 2.0 compliance.
•
Value of pull-ups resistors
determined by line load. Typical
value used is 8.2 k
Ω
± 5%
.
•
Refer to
INTRUDER#
•
Pull signal to VCCRTC (VBAT) if not
needed.
•
Signal in VCCRTC (VBAT) well.
•
Refer to
.
Table 13-3. Intel
®
ICH3-S Schematic Checklist (Sheet 7 of 8)
Checklist Items
Recommendations
Comments
Summary of Contents for Xeon
Page 24: ...Introduction 24 Design Guide This page is intentionally left blank ...
Page 30: ...Component Quadrant Layout 30 Design Guide This page is intentionally left blank ...
Page 52: ...Platform Clock Routing Guidelines 52 Design Guide This page is intentionally left blank ...
Page 66: ...System Bus Routing Guidelines 66 Design Guide This page is intentionally left blank ...
Page 118: ...Intel 82870P2 P64H2 118 Design Guide This page is intentionally left blank ...
Page 146: ...I O Controller Hub 146 Design Guide This page is intentionally left blank ...
Page 148: ...Debug Port 148 Design Guide This page is intentionally left blank ...
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