59
PCI-X Layout Guidelines
6.4.13
PCI-X 66 MHz Mixed Mode Topology
and
provides routing details for a topology with for an embedded PCI-X
66 MHz design with slots.
Microstrip Trace Spacing
18 mils, from edge to edge
Group Spacing
Spacing from other groups: 25 mils minimum center to center
Trace Length 1 (TL1): From
80331 signal Ball to first
junction
1.0” minimum - 5.0” maximum
Trace Length TL2 to TL3
between junctions
1.0” minimum - 2.5” maximum
Trace Length TL_EM1 to
TL_EM6 - from junction to
embedded devices
2.0” minimum - 3.0” maximum
Length Matching
Requirements:
No length matching is required among datalines. For length matching for clocks,
refer clock guidelines
.
Number of vias
Four vias maximum
Table 19.
PCI-X 66 MHz Embedded Routing Recommendations (Sheet 2 of 2)
Figure 28.
PCI-X 66 MHz Mixed Mode Routing Topology
Table 20.
PCI-X 66 MHz Mixed Mode Routing Recommendations (Sheet 1 of 2)
Parameter
Routing Guideline for AD Bus
Routing Guideline for Upper AD Bus
Reference Plane
Route over an unbroken ground plane
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 minimum center to center
Trace Length 1 TL1: From
80331 signal Ball to first slot
1.0” minimum - 5.0” maximum
1.0” minimum - 4.5” maximum
CONN1
TL_A
D
1
TL3
CONN2
TL_A
D
2
AD1
AD2
TL4
CONN3
TL_A
D
3
AD3
TL1
TL_E
M1
EM1
Summary of Contents for 80331
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