Example Topologies For Ddr Trace; Ohm Differential Trace - Intel 80331 Design Manual

Table 31.

Example Topologies for DDR Trace

Topology
Microstrip
(layers 1 or 8)
Stripline
(layers 3 or 6)
1. Microstrip Differential Lines: Motherboard/Add-in 100 ohm: Constructed by two microstrips of 5 mils traces
separated by center to center distance of 13 mils as shown in
2. Strip Differential Lines: Motherboard Stripline 100 ohms: Constructed by two striplines of 4 mils traces
separated by center to center distance of 12 mils as shown in
3. Strip Differential Lines: Add-in stripline 100 ohms: Constructed by two striplines of 4 mils traces separated by
center to center distance of 13 mils as shown in
Figure 35.

100 ohm Differential Trace

Min Trace
Trace Width
Spacing
(mils)
(mils)
5 5
7 12
6 12
4 12
5 (note 1) 20
5 5
6 12
5 12
7 12
6 12
4 12
4 (note 2) 20
5 (note 3) 20
100 Ω
Diff +
Other
Signals
4/5 mils
20 mils Spacing
Intel® 80331 I/O Processor Design Guide
Trace
Preferred
Impedance
signals
(ohms)
Breakout
Address/
45
CMD/Control
50
60
Differential
100 differential
Clock/DQS
Break out
45 DQ/DQS/CB
50
45 DQ/DQS/CB
50
60
Differential
100 Ohm
Clocks
Differential
100 Ohm
Clock
Figure 35.
Figure 35.
Figure 35.
Differential Trace
Center to Center
(12/13 mils
Diff -
4/5 mils
20 mils Spacing
Memory Controller
Board Type
Motherboard/Add-in
Motherboard/Add-in
Motherboard/Add-in
Motherboard/Add-in
Motherboard/Add-in
Motherboard/Add-in
Motherboard
Motherboard card
Add-in card
Add-in card
Add-in card
Motherboard*
Add-in card*
Other
Signals
B2530-02
71