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Intel
®
810A3 Chipset Design Guide
4-11
Layout and Routing Guidelines
4.7.4
Compensation
There are two options for the ICH hub interface compensation (HLCOMP). HLCOMP is used by
the ICH to adjust buffer characteristics to specific board characteristics. Refer to the Intel
®
82801AA (ICH) and Intel
®
82801AB (ICH0) I/O Controller Hub Datasheet for details on
compensation. It can be used as either Impedance Compensation (ZCOMP) or Resistive
Compensation (RCOMP). The guidelines are below:
•
RCOMP: Tie the HLCOMP pin to a 40
Ω
1% or 2% pull-up resistor (to 1.8V) via a 10 mil
wide, 0.5” trace (targeted for a nominal trace impedance of 40
Ω
).
•
ZCOMP: The HLCOMP pin should be tied to a 10 mil trace that is AT LEAST 18” long. This
trace should be unterminated and care should be taken when routing the signal to avoid
crosstalk (15-20 mil separation between this signal and any adjacent signals is recommended).
This signal may not cross power plane splits.
The GMCH also has a hub interface compensation pin. This signal (HLCOMP) can be routed using
either the RCOMP method or ZCOMP method described for the ICH.
Figure 4-13. Single Hub Interface Reference Divider Circuit
Figure 4-14. Locally Generated Hub Interface Reference Dividers
H U B R E F
H U B R E F
G M C H
ICH
300
Ω
1.8V
300
Ω
0.01 uF
0.01 uF
0.1 uF
H U B R E F
H U B R E F
G M C H
ICH
300
Ω
1.8V
300
Ω
0.01 uF
300
Ω
1.8V
300
Ω
0.01 uF
Содержание 810A3
Страница 1: ...Intel 810A3 Chipset Platform Design Guide July 2000 Order Number 298186 002...
Страница 11: ...1 Introduction...
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Страница 25: ...2 PGA370 Processor Design Guidelines...
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Страница 41: ...3 SC242 Processor Design Guidelines...
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Страница 51: ...4 Layout and Routing Guidelines...
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Страница 93: ...5 Advanced System Bus...
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Страница 115: ...6 Clocking...
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Страница 123: ...7 System Design Considerations...
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Страница 137: ...8 Design Checklist...
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Страница 157: ...9 Third Party...
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Страница 163: ...A PCI Devices Functions Registers Interrupts...
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