Mobile Intel Pentium 4 Processor - M and Intel 845MP/MZ Chipset Platform Design Guide

Mobile Intel

Pentium

4 Processor-M and Intel

845MP/845MZ Chipset Platform

Design Guide 157

Figure 88. Topology for PCICLK to PCI Slot

Clock

Driver

PCI Device

B C

PCI

Connector

Trace on PCI

Card

Table 56. PCICLK Routing Guidelines

Parameter Routing Guidelines

Clock Group PCICLK

Topology Point to point

Reference Plane Ground Referenced (Contiguous over entire Length)

Characteristic Trace Impedance (Zo) 50 Ohms ± 15%

Trace Width 5 mils

Trace Spacing 10 mils

Spacing to other traces 10 mils

Trace Length – A Same as CLK33 Trace A

This trace must be exactly length matched to CLK33 Trace A

Trace Length – B (Routed equal to CLK33 Trace B) – 2.5”

Trace Length – C Routed 2.50” per the PCI Specification

Resistor R1 = 33 Ohms ± 1%

Skew Requirements Should have a maximum of ±1 ns skew between the clocks within this

group, and also a maximum of

±1 ns skew between the clocks of this

group and that of group CLK33.

Maximum via Count per signal 1