132
Intel
®
855GME Chipset and Intel
®
6300ESB ICH Embedded Platform Design Guide
System Memory Design Guidelines (DDR-SDRAM)
presents the data signal group routing guidelines.
Table 32. Data Signal Group Routing Guidelines
Parameter
Definition
Signal Group
SDQ[71:0], SDQS[8:0], SDM[8:0]
Motherboard Topology
Daisy Chain with Parallel Termination
Reference Plane
Ground Referenced
Characteristic Trace Impedance (Zo)
55
Ω
± 15%
Nominal Trace Width
Inner layers: 4 mils
Outer layers: 5 mils
Minimum Spacing to Trace Width Ratio
SDQ/SDM: 2:1 (e.g., 8 mil space to 4 mil trace)
SDQS: 3 to 1 (e.g., 12 mil space to 4 mil trace)
Minimum Isolation Spacing to non-DDR Signals
20 mils
Package Length P1
700 mils ± 300 mils
Refer to package length for details.
Trace Length P1+ L1 – GMCH Die-Pad to Series
Termination Resistor Pad
Min = 2”-L2
Max = 6”-L3-L2
Trace Length L2 – Series Termination Resistor Pad to
First DIMM Pad
Max = 0.75”
Total Length P1+ L1+L2 – Total Length from GMCH to
First DIMM Pad
Min = 2.0”
Max = 6”-L3
Trace Length L3 – First DIMM Pad to Last DIMM Pad
Min = 0.25”
Max = 2.0”
Trace Length L4 – Last DIMM Pad to Parallel
Termination Resistor Pad
Max = 1.0”
Total Length P1+ L1+L2+L3 – Total Length from GMCH
to Second DIMM Pad
Min = 2”+L3
Max = 6.0”
Series Termination Resistor (Rs)
10
Ω
± 5%
Parallel Termination Resistor (Rt)
56
Ω
± 5%
Maximum Recommended Motherboard Via Count Per
Signal
6
Length Matching Requirements
Match SDQS to SCK/SCK#
and
SDQ/SDM to SDQS, to ± 25 mils, within each
byte lane.
and
NOTES:
1. Power distribution vias from Rt to Vtt are not included in this count.
2. The overall minimum and maximum length to the DIMM must comply with clock length matching
requirements.
Содержание 6300ESB ICH
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Страница 36: ...36 Intel 855GME Chipset and Intel 6300ESB ICH Embedded Platform Design Guide General Design Considerations...
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Страница 152: ...152 Intel 855GME Chipset and Intel 6300ESB ICH Embedded Platform Design Guide System Memory Design Guidelines DDR SDRAM...
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Страница 190: ...190 Intel 855GME Chipset and Intel 6300ESB ICH Embedded Platform Design Guide Hub Interface...
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Страница 264: ...264 Intel 855GME Chipset and Intel 6300ESB ICH Embedded Platform Design Guide Platform Clock Routing Guidelines...
Страница 298: ...298 Intel 855GME Chipset and Intel 6300ESB ICH Embedded Platform Design Guide Schematic Checklist Summary...
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