Intel 31244 PCI-X User Manual
45
Printed Circuit Board (PCB) Methodology
6.2.4
Cable Interconnect With Backplane
provides the topology which uses a cable as an interconnect between the motherboard
and backplane.
Table 15.
Backplane Stackup, Microstrip
Variable
Nominal (mil)
Tolerance
Min (mil)
Max (mil)
Mask Thickness
0.8
+/- 0.2
0.6
1.0
Mask Er
3.6
3.6
3.6
Trace Height
1.4
+/-0.3
1.1
1.7
Preg Er
4.66
+/-0.55
3.6
4.7
Plane Thickness
1.4
+/-0.2
1.2
1.6
Trace Thickness
1.4
+/-0.4
1.0
1.8
Trace Width
11.5
+/-1.5
10
13
Total Thickness
70.0
+/-7.0
63.0
77.0
Table 16.
Backplane Stackup, Offset Stripline
Variable
Nominal (mil)
Tolerance
Min (mil)
Max (mil)
Mask Thickness
0.8
+/- 0.2
0.6
1.0
Mask Er
3.6
3.6
3.6
Trace Height
1
+/-0.3
Preg Er
4.15
+/-0.55
3.6
4.7
Plane Thickness
2.2
+/-0.2
1.2
1.6
Trace Thickness
1.4
+/-0.4
1.8
2.6
Trace Width
11.5
+/-1.5
Total Thickness
70.0
+/-7.0
63.0
77.0
Table 17.
Cable Specification
Parameter
Routing Guideline
Notes
Characteristic Z - Cable
100 ohms +/- 15%
Trace Length
1”-6”
Trace Matching
150 mils