Intel Xeon User Manual

Schematic Checklist
200 Design Guide
GNT[4:0]# • No external pull-up resistors are required on
PCI GNT signals. However, if external pull-
up resistors are implemented, they must be
pulled up to VCC3.3.
• These signals are actively
driven by the ICH3-S.
PME# • No extra pull-up resistor. • This signal has integrated pull-
up of 18 k
Ω to 42 kΩ.
GNT[A]# /GPIO[16]
GNT[B]#/ GNT[5]#/
GPIO[17]
• No extra pull-up needed. • These signals have integrated
pull-ups of 24 k
Ω.
• GNT[A] has an added strap
function of “top block swap.”
The signal is sampled on the
rising edge of PWROK. Default
value is high or disabled due to
pull-up. A Jumper to a pull-
down resistor can be added to
manually enable the function.
Power
V_CPU_IO[2:0] • The power pins should be connected to the
proper power plane for the processor CMOS
compatibility signals. Use one 0.1 µF
decoupling capacitor.
• Used to pull-up all processor I/F
signals.
VCCRTC • No clear CMOS jumper on VCCRTC. Use a
jumper on RTCRST# or a GPI, or use a safe
mode strapping for Clear CMOS.
VCC_3.3 • Use six 0.1 µF decoupling capacitors.
VCCSUS_3.3 • Use two 0.1 µF decoupling capacitors.
VCC_1.8 • Use four 0.1 µF decoupling capacitors.
VCCSUS_1.8 • Use one 0.1 µF decoupling capacitor.
V5_REF_SUS • Use one 0.1 µF decoupling capacitor.
• V5REF_SUS is the reference voltage for
some 5 V tolerant inputs in the ICH3-S.
V5REF_SUS must power up before or
simultaneous to VCCSUS3.3. It must power
down after or simultaneous to VCCSUS3.3.
(For most platforms this sequencing isn’t an
issues because VCCSUS3.3 is derived from
V5SUS.
V5_REF • Requires one 0.1 µF decoupling capacitor.
• V5_REF is the reference voltage for most
5V tolerant inputs in the ICH3-S. Tie to pins
V5REF[2:1]. V5REF must power up before
or simultaneous to VCC_3.3. It must power
down after or simultaneous to VCC_3.3.
• If USB is implemented in the platform,
V5REF_Sus must be connected to VSus5.
• Refer to Figure 12-22 for an
example circuit schematic that
may be used to ensure the
proper V5REF sequencing.
Table 13-3. Intel
®
ICH3-S Schematic Checklist (Sheet 5 of 8)
Checklist Items Recommendations Comments

Intel Xeon Specifications

General

Brand	Intel
Model	Xeon
Category	Processor
Language	English