Hardware Design Guide
113
IXP28XX Network Processor
PCI
Table 39
provides routing guidelines for the PPCI address/data group parameters.
6.2.1.2
PPCI Clock Signals
Figure 65
illustrates the topology for PPCI clock signals. All of the clock signal traces for the PPCI
bus should be matched.
Figure 64.
PPCI Address/Data Signal Topology
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Table 39.
PPCI Address/Data Group Guidelines
Parameter
Routing Guidelines
Signal Group
Address/Data
Topology
Daisy Chain
Reference Plane
Dual-referenced, PWR–SIG–GND
Characteristic Trace Impedance
60
Ω
± 10%
Nominal Trace Width
3.5 mils
Nominal Trace Separation
9.0 mils
Spacing to Other Groups
20 mils
Trace Length A
Maximum = 50 mils
Trace Length B
Maximum = 4200 mils
Trace Length C
Maximum = 4500 mils
Trace Length D
Maximum = 50 mils
Trace Length E
Maximum = 1200 mils
Trace Length F
Maximum = 2500 mils
Maximum Via Count per Signal
8 Vias
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