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Platform Power Delivery Guidelines
11.7.9.
CK-408 Clock Driver Decoupling
The decoupling requirements for a CK-408 compliant clock synthesizer are often dependent on vendor
design and implementation. The appropriate decoupling guidelines in terms of type, quantity, form
factor, and usage of decoupling capacitors should come from the respective clock synthesizer
component vendor.
If clock synthesizer specific decoupling guidelines from a vendor are not available, the general
guidelines below can be used.
The decoupling caps should be connected taking care to connect the VDD pins directly to the VDD side
of the caps. However, the VSS pins should not be connected directly to the VSS side of the caps.
Instead, they should be connected to the ground flood under the part that is via'ed to the ground plane.
This is done to avoid VDD glitches propagating out and getting coupled through the decoupling caps to
the VSS pins. This method has been shown to provide the best clock performance.
The decoupling requirements for a CK-408 compliant clock synthesizer are as follows:
One 10-µF bulk decoupling cap in a 1206 package placed close to the VDD generation circuitry.
Six 0.1-µF high frequency decoupling caps in a 0603 package placed close to the VDD pins on the
CK-408.
Three 0.1-µF high frequency decoupling caps in a 0603 package placed close to the VDDA pins on
the CK-408.
One 10-µF bulk decoupling cap in a 1206 package placed close to the VDDA generation circuitry
11.8.
Intel 855PM MCH Power Consumption Numbers
The following table shows the Intel 855PM MCH power consumption estimates.
Table 84. Intel 855PM MCH Power Consumption Estimates
Power Plane
V
(1.05 V)
CCP
V
(1.2 V Core)
CC-MCH
VCC1_5 (AGP)
VCC1_8 (HI 1.0)
VCCA (PLL 1.8 V)
VCCSM (DDR 2.5 V)
SMVREF
SMRCOMP
268
Maximum Power Consumption
S0
S1M
2.4 A
36 mA
1.65 A
66 mA
370 mA
4 mA
200 mA
43 mA
N/A
N/A
1.9 A
< 1 mA
50 A
N/A
80 mA
N/A
S3
S4/S5
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
< 1 mA
N/A
0 mA
N/A
0 mA
N/A
®
Intel
855PM Chipset Platform Design Guide
R
G3
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
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