53
PCI-X Layout Guidelines
6.4.7
PCI-X 100 MHz Slot Topology
and
provide details on the PCI-X 100 MHz slot topology.
Figure 22.
Slot PCI-X 100 MHz Slot Routing Topology
Table 14.
PCI-X 100 MHz Slot Topology Routing Recommendations
Parameter
Routing Guideline for Lower AD Bus Routing Guideline for Upper AD Bus
Reference Plane
Preferred Layer
Route over an unbroken ground plane
Stripline
Breakout
5 mils on 5 mils spacing. Maximum length of the breakout is 500 mils.
Motherboard Trace
Impedance (microstrip and
stripline)
50 Ohms +/- 15%
Add-in card Impedance
(microstrip and stripline)
57 Ohms +/- 15%
Stripline Trace Spacing
12 mils, from edge to edge
Microstrip Trace Spacing
18 mils, from edge to edge
Group Spacing
Spacing from other groups: 25 mils min, center to center
Trace Length 1 TL1: From
80331 signal Ball to first
junction
1.0” minimum - 9.5” maximum
1.0” - 7.0” maximum
Trace Length TL2 - between
junction and connector
0.8” - 1.1” maximum
0.8” - 1.1” maximum
Trace Length TL_AD1,
TL_AD2- from connector to
receiver
0.75” minimum - 1.5” maximum
1.75” minimum - 2.75” maximum
Length Matching
Requirements:
No length matching is required among datalines. For length matching for clocks,
refer clock guidelines
.
Number of vias
Three vias max
TL2
CONN1
T
L_A
D1
TL3
CONN2
TL
_A
D
2
AD1
AD2
TL1
Summary of Contents for 80331
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