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Intel 31154 manual Trace Impedance, Routing Guidelines

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Routing Guidelines

6.4Trace Impedance

The PCI-X Addendum to the PCI Local Bus Specification, Revision 1.0b, recommends that all signal layers have a controlled impedance of 57 Ω ±10% for add-in card applications. The characteristic impedance of a signal trace is 60–100Ω for PCI add-in card applications.

Selecting the appropriate board stack-up to minimize impedance variations is very important. When calculating flight times, it is important to consider the minimum and maximum trace impedance based on the switching neighboring traces. The PCI Local Bus Specification, Revision 2.3, recommends a trace velocity of 150 ps/in to 190 ps/in. Use wider spaces between traces, since this can minimize trace-to-trace coupling, and reduce crosstalk.

When a different stack-up is used, the trace widths must be adjusted appropriately. When wider traces are used, the trace spacing must be adjusted accordingly (linearly).

It is highly recommended that a 2D field solver be used to design the high-speed traces. An impedance calculator, available at http://emclab.umr.edu/pcbtlc, provides approximations for the trace impedance of various topologies. These approximations may be used to generate the starting point for a full 2D field solver.

The following website provides a useful basic guideline for calculating trace parameters:

http://www.ultracad.com/calc.htm

Note: Using stripline transmission lines may give better results than microstrip. This is due to the difficulty of precisely controlling the dielectric constant of the solder mask, and the difficulty in limiting the plated thickness of microstrip conductors, which can substantially increase crosstalk.

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Intel® 31154 133 MHz PCI Bridge Design Guide Design Guide

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Intel manual Trace Impedance, Routing Guidelines, Intel 31154 133 MHz PCI Bridge Design Guide Design Guide

Contents

Design Guide Intel 31154 133 MHz PCI Bridge Design GuideApril Intel 31154 133 MHz PCI Bridge Design Guide Contents ContentsIntel 31154 133 MHz PCI Bridge Design Guide Intel 31154 133 MHz PCI Bridge Design Guide FiguresTables ContentsIntel 31154 133 MHz PCI Bridge Design Guide ContentsDate Revision HistoryContents Intel 31154 133 MHz PCI Bridge Design GuideTerminology and Definition Sheet 1 of About This Document1.1 Terminology and Definitions About This DocumentTerm Table 1. Terminology and Definition Sheet 2 ofAbout This Document Intel 31154 133 MHz PCI Bridge Design Guide Design GuideIntroduction PCI-to-PCI Bridge ConfigurationsIntroduction2 2.1 Product OverviewPCI-to-PCI Bridge Architecture Specification, Revision 1.2 compliant 2.2 Features ListFeatures List PCI Local Bus Specification, Revision 2.3 compliantPCI Bus Power Management Interface Specification, Revision 2.3 Related External SpecificationsPCI Local Bus Specification, Revision PCI-to-PCI Bridge Architecture Specification, RevisionTHIS PAGE INTENTIONALLY LEFT BLANK IntroductionIntel 31154 133 MHz PCI Bridge Design Guide Design Guide Package Information Package InformationIntel 31154 133 MHz PCI Bridge Design Guide Design Guide BOTTOM VIEW Figure 2. Intel 31154 133 MHz PCI Bridge PackagePackage Information Intel 31154 133 MHz PCI Bridge Design Guide Design GuideAC VSS Figure 3. Intel 31154 133 MHz PCI Bridge Ball Map-Top View, Left SidePackage Information Intel 31154 133 MHz PCI Bridge Design Guide Design GuideVCCA Package InformationIntel 31154 133 MHz PCI Bridge Design Guide Design Guide 13 14 15 16 17 18 19 20Package Information 3.1 Total Signal CountTotal Signal Count SignalsPackage Information THIS PAGE INTENTIONALLY LEFT BLANKIntel 31154 133 MHz PCI Bridge Design Guide Design Guide Intel 31154 133 MHz PCI Bridge Design Guide Design Guide Terminations4Terminations Pull-Up/Pull-Down Terminations Sheet 1 ofTerminations Pull-Up/Pull-Down Terminations Sheet 2 ofSignal Secondary PCI SignalsIntel 31154 133 MHz PCI Bridge Design Guide Design Guide Pull-Up/Pull-Down Terminations Sheet 3 ofSignal TerminationsIntel 31154 133 MHz PCI Bridge Design Guide Design Guide Pull-Up/Pull-Down Terminations Sheet 4 ofSignal TerminationsTerminations Pull-Up/Pull-Down Terminations Sheet 5 ofSignal resistor defaultIntel 31154 133 MHz PCI Bridge Design Guide Design Guide Pull-Up/Pull-Down Terminations Sheet 6 ofSignal Terminations“Power Sequencing” on page Pull-Up/Pull-Down Terminations Sheet 7 ofSignal “Power Sequencing” on pageIntel 31154 133 MHz PCI Bridge Design Guide Design Guide Pull-Up/Pull-Down Terminations Sheet 8 ofSignal TerminationsIntel 31154 133 MHz PCI Bridge Design Guide Design Guide Pull-Up/Pull-Down Terminations Sheet 9 ofSignal TerminationsTerminations THIS PAGE INTENTIONALLY LEFT BLANKIntel 31154 133 MHz PCI Bridge Design Guide Design Guide PCI/PCI-X Interface PCI/PCI-X Interface5.1 PCI/PCI-X Voltage Levels 5.2 Interrupt RoutingIDSEL Mapping 5.3 IDSEL Lines5.3.1 Primary IDSEL Line 5.3.2 Secondary IDSEL Lines5.3.4 Secondary Clock Control 5.5 Opaque Memory Region Enable5.3.3 Secondary IDSEL Masking 5.4 CompactPCI* Hot Swap Mode SelectPCI/PCI-X Interface 5.6 PCI-X Initialization Clocking Modes5.6.1 Primary PCI Clocking Mode 5.6.2 Secondary PCI Clocking ModeIntel 31154 133 MHz PCI Bridge Design Guide Design Guide PCI-X Clocking ModesSecondary Bus Frequency Initialization PCI/PCI-X InterfaceIntel 31154 133 MHz PCI Bridge Design Guide Design Guide 5.6.3 Primary-to-Secondary Frequency LimitsPCI-X Initialization Pattern PCI/PCI-X InterfaceRouting Guidelines Routing GuidelinesIntel 31154 133 MHz PCI Bridge Design Guide Design Guide Intel 31154 133 MHz PCI Bridge Design Guide Design Guide 6.1 CrosstalkFigure 6. Crosstalk Effects on Trace Distance and Height Routing GuidelinesIntel 31154 133 MHz PCI Bridge Design Guide Design Guide Figure 7. PCB Ground Layout Around Connectors6.2 EMI Considerations Routing GuidelinesRouting Guidelines 6.3 Power Distribution and Decoupling6.3.1 Decoupling Recommendations Table 11. Intel 31154 133 MHz PCI Bridge Decoupling Recommendations6.4 Trace Impedance Routing GuidelinesIntel 31154 133 MHz PCI Bridge Design Guide Design Guide Routing Guidelines THIS PAGE INTENTIONALLY LEFT BLANKIntel 31154 133 MHz PCI Bridge Design Guide Design Guide Intel 31154 133 MHz PCI Bridge Design Guide Design Guide PCI-X Layout GuidelinesPCI-X Layout Guidelines Add-in Card Routing Parameters7.1 PCI Clock Layout Guidelines PCI-X Layout GuidelinesIntel 31154 133 MHz PCI Bridge Design Guide Design Guide Notes -3%%% ####Intel ####%,%!#%#Intel 31154 133 MHz PCI Bridge Design Guide Design Guide 7.2 PCI-X Topology Layout GuidelinesPCI-X Slot Guidelines PCI-X Layout GuidelinesPCI-X Layout Guidelines Wiring Lengths for 133 MHz Slot7.2.1 Single Slot at 133 MHz Figure 9. Single-Slot Point-to-Point TopologyB3058-01 Wiring Lengths for Embedded 133 MHz DesignPCI-X Layout Guidelines Intel 31154 133 MHz PCI Bridge Design Guide Design GuidePCI-X Layout Guidelines Figure 11. Dual-Slot ConfigurationWiring Lengths for 100 MHz Dual-Slot 7.2.2 Dual-Slot at 100 MHzLower AD Bus Wiring Lengths for Embedded 100 MHz DesignPCI-X Layout Guidelines Intel 31154 133 MHz PCI Bridge Design Guide Design GuidePCI-X Layout Guidelines Table 18. Wiring Lengths for 66 MHz Quad-Slot Sheet 1 of7.2.3 Quad-Slots at 66 MHz Figure 13. Quad-Slots 66 MHz TopologyLower AD Bus Table 18. Wiring Lengths for 66 MHz Quad-Slot Sheet 2 ofPCI-X Layout Guidelines Intel 31154 133 MHz PCI Bridge Design Guide Design GuidePCI-X Layout Guidelines Figure 14. Embedded Intel 31154 133 MHz PCI Bridge Wiring for 66 MHzWiring Lengths for Embedded 66 MHz Design 7.2.3.1 Embedded Intel 31154 133 MHz PCI Bridge Application at 66 MHzPCI-X Layout Guidelines 7.2.4.1 Embedded PCI-X Specification PICMG 1.2 Overview7.2.4 PCI-X at 33 MHz 7.2.4.2 PICMG 1.2 System OverviewFigure 15. An Example of an ePCI-X System PCI-X Layout GuidelinesIntel 31154 133 MHz PCI Bridge Design Guide Design Guide Intel 31154 133 MHz PCI Bridge Design Guide Design Guide Table 20. Wiring Lengths for PICMG 1.2 BackplaneFigure 16. PCI-X Data Bus PICMG 1.2 Style Backplane PCI-X Layout GuidelinesSlotN Table 21. PCI-X Clock Wiring Lengths for PICMG BackplaneFigure 17. PCI-X Clock PICMG 1.2 Style Backplane Slot1PCI-X Layout Guidelines THIS PAGE INTENTIONALLY LEFT BLANKIntel 31154 133 MHz PCI Bridge Design Guide Design Guide Intel 31154 133 MHz PCI Bridge Design Guide Design Guide Power Considerations8.1 Analog Power Pins Power ConsiderationsIntel 31154 133 MHz PCI Bridge Design Guide Design Guide 8.2 Power SequencingIntel 133 MHz PCI Bridge Power Considerations133 MHz PCI Bridge Figure 21. Intel IQ31154 Customer Reference Board Block DiagramCustomer Reference Board IntelCustomer Reference Board Stackup Customer Reference BoardIntel 31154 133 MHz PCI Bridge Design Guide Design Guide Intel 31154 133 MHz PCI Bridge Design Guide Design Guide Debug Connectors and Logic Analyzer Connectivity1010.1 Probing PCI-X Signals Debug Connectors and Logic Analyzer ConnectivityLogic Analyzer Pod Debug Connectors and Logic Analyzer ConnectivityIntel 31154 133 MHz PCI Bridge Design Guide Design Guide Debug Connectors and Logic Analyzer Connectivity Logic Analyzer PodIntel 31154 133 MHz PCI Bridge Design Guide Design Guide AD15 Debug Connectors and Logic Analyzer ConnectivityLogic Analyzer Pod Intel 31154 133 MHz PCI Bridge Design Guide Design GuideDebug Connectors and Logic Analyzer Connectivity Logic Analyzer PodIntel 31154 133 MHz PCI Bridge Design Guide Design Guide Intel 31154 133 MHz PCI Bridge Design Guide Design Guide Debug Connectors and Logic Analyzer ConnectivityPCI-X Signal Name Logic Analyzer PodIntel 31154 133 MHz PCI Bridge Design Guide Design Guide Debug Connectors and Logic Analyzer ConnectivityThe recommended placement of the Mictor connectors is at either end of the bus segment. The Mictors are placed at the end of a stub that must be as short as possible, and are then daisy-chained off either end of the bus. When there is not enough room to place the Mictors at least 0.5 from the target, an alternate method can be used. This alternate method is to place the logic analyzer termination circuitry on the target and then extend the etch from the end of the termination circuitry over to the Mictor connectors. The connection from the Mictors to the logic analyzer must then be made with the E5351A. The E5346A contains the logic analyzer termination circuitry, and the E5351A does not Logic Analyzer PodDebug Connectors and Logic Analyzer Connectivity THIS PAGE INTENTIONALLY LEFT BLANKIntel 31154 133 MHz PCI Bridge Design Guide Design Guide Maximum Power Thermal SolutionsThermal Solutions Table 29. Operational PowerThermal Solutions THIS PAGE INTENTIONALLY LEFT BLANKIntel 31154 133 MHz PCI Bridge Design Guide Design Guide Table 30. Design Reference Material References1212.1 Related Documents ReferencesReferences THIS PAGE INTENTIONALLY LEFT BLANKIntel 31154 133 MHz PCI Bridge Design Guide Design Guide