106
Memory Controller
Table 59.
DDR II 400 DIMM DQ Lengths
Traces
Description
Layer
Minimum
Length
Maximum
Length
Trace
Impedance
Spacing
(edge to
edge)
Notes
TL0
Breakout
Microstrip
0”
0.5”
5 mils
5 mils trace width OK for
breakout.
TL1
Lead-in
Microstrip
2 “
8”
45 ohms or 50
ohms
Same
group 12
mils
Other
groups
20 mils
Figure 50.
DDR II 400 DIMM DQ Topology
Table 60.
DDR II 400 DIMM DQS Lengths
Traces
Description
Layer
Minimum
Length
Maximum
Length
Trace
Impedance
Spacing
(edge to
edge)
Notes
TL0
Breakout
Microstrip
0”
0.5”
5 mils
5 mils trace width OK for
breakout.
TL1
Lead-in
Microstrip
2 “
8”
Differential 100
ohm impedance
20 mils
from
other
signals
Route as differential pair.
•
Motherboard 100 ohm
differential constructed by
stripline of two 4 mil traces
separated by center to
center distance of 12 mils.
•
Add-in card 100 ohm
differential constructed by
stripline of two 5 mil traces
separated by center to
center distance of 12 mils.
Figure 51.
DDR II 400 DIMM DQS Topology
DIMM
TL0
TL1
TL0
TL1
Summary of Contents for 80331
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