OrCAD X Resources

3. Choose Create - Electrical CSet… 4. Give the ECSet a name and it will be added to the spreadsheet. 5. Once added, enter a desired maximum stub length for the ECSet. 6. For example, let's say you want your stubs to be no more than 8 mils (0.0203 mm), so you enter '8 mils' in the rule shown below for the DIFF signal constraint set. 7. Now let's apply that constraint and the stub rule it has. 8. In the Constraint Manager go to Electrical > Net > Routing > Wiring. 40 www.cadence.com OrCAD X Constraint Management Guide

• DG-ORCDX-CNSTMG-cover
• orcad-x-constraint-management-guide-part-1
• Part 1 - Introduction to Constraint Management
• What is Constraint Management?
• Problems Solved by Constraint Management
• Benefits of Proper Constraint Management
• Applications of Constraint Management
• Finding the Constraint Manager (CM)
• Understanding How the Constraint Manager Works
• Types of Constraints
• Electrical Constraints
• Physical Constraints
• Spacing Constraints
• Manufacturing Constraints
• High-Speed Design Constraints
• Understanding Net Classes, Net Groups, and Regions in PCB Design
• 1. Net Classes
• Example - Creating a Net Class
• 2. Net Groups
• Example - Create a Net Group
• 3. Regions
• Region Physical Constraint Set
• Region Spacing Constraint Set
• Manual Constraint Entry vs. Constraint Sets
• Applying The Constraint Region
• Key Differences and Implications Among Net Classes, Groups, and Constraint Regions
• Summary
• Conclusion to Part 1
• orcad-x-constraint-management-guide-part-2
• Part 2 - Standard Constraints
• Physical and Spacing Constraints
• Trace Width: Minimum and Maximum Width for Signal And Power Traces.
• Via Size: Diameter and pad size for vias, including microvias and blind/buried vias.
• Differential Pairs (Basic Setup)
• Creating a Diff Pair
• Spacing Constraints
• Creepage and Clearance: Minimum Distances Between Conductive Elements to Prevent Electrical Arcing
• Component Spacing: Minimum Distances Between Components to Avoid Interference and Facilitate Cooling
• Manufacturing Constraints
• Fabrication Tolerances: Allowable Variations in Dimensions for Manufacturing
• Board Outline Dimensions: Tolerances for Overall Board Size and Shape
• Trace Width for Manufacturing: Minimum Copper Width for Traces
• Trace Spacing: Minimum Distance Between Copper Features
• Annular Ring: Minimum Width of Copper Surrounding a Hole
• Drill to Copper Spacing
• Teardrops (Fillets)
• Pad To Mounting Hole Spacing: Minimum Distance Between Pads and Mounting Holes
• Acid Traps: Avoiding Acute Angles in Copper Features That Can Trap Etching Chemicals
• Minimum Copper Area: Smallest Allowable Area of Isolated Copper Features
• Assembly Constraints: Rules for Component Placement, Orientation, and Soldering
• Outlines and Cut Outs
• Where to Apply the Constraint Set
• Package to Package Spacing
• Component Spacing to PCB Features
• Pastemask
• Silkscreen and Solder Mask: Specifications for Text and Mask Application on The PCB.
• Design for Test (DFT) Constraints
• Test Points: Placement and Minimum Distances From Other Test Points and Components
• 3D Constraints
• Rigid Flex PCB Constraints
• Teardrops (Fillets)
• Component to Flex PCB
• Conclusion
• orcad-x-constraint-management-guide-part-3
• Part 3 - Advanced Constraints
• Constraint Modes
• Signal Integrity
• Impedance Control: Specification for controlled impedance traces for high-speed signals
• Crosstalk Mitigation: Maximum parallel trace length
• EMC and EMI
• Return Path
• High-speed constraints/electrical design rules:
• Min/max relative propagation delay: Controlling signal timing
• Critical Trace Length
• Length Matching
• Differential pairs (High-Speed)
• Other High-Speed Constraints
• Wiring topology
• Stub limits (Max Stub Length)
• Maximum stub exposed length
• Layer restrictions
• Maximum Via Count
• Example Constraints for Common Applications
• USB (Universal Serial Bus) Constraints
• Double Data Rate (DDR) Constraints
• Rigid-Flex PCB Constraints
• RF (Radio Frequency) Circuit Constraints
• Conclusion of Part 3 - Advanced Constraints
• orcad-x-constraint-management-guide-part-4
• Part 4 – Constraints Optimization
• Constraint Efficiencies
• Constraint Sets
• Modular Approach To Constraint Management
• Schematic to PCB Constraints
• Importing and Exporting Constraints
• Conclusion to Part 4 - Constraints Optimization
• orcad-x-constraint-management-guide-part-5
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• Part 5 – Project Example in OrCAD X
• Hardware Design Project
• Modern Hardware Design Process
• Organize the Nets
• Define Net Classes
• Define Net Groups
• Decide On Constraint Regions
• Setting Spacing Regions
• Schematic Constraints Overview
• Electrical Constraints
• Physical Constraints
• Physical Constraint Set
• Applied Constraint Set
• Spacing Constraints
• Spacing Constraint Set
• Electrical Properties
• PCB Constraints Overview
• PCB Stack up
• Opening The Constraint Manager (PCB Side)
• All Constraints for Analysis
• Applying Standard PCB Constraints
• Trace Width
• Differential Pairs
• Physical Region
• Applying High-Speed and Advanced Constraints
• Advanced Constraints Application
•  Advanced Electrical Constraints
• Wiring topology
• Stub Length (Max Stub Length)
• Maximum Exposed Length
• Maximum parallel trace length
• Layer restrictions
• Maximum via count
• Characteristic impedance
• Propagation delay modeling
• Total etch length limits
• Differential pair rules
• Relative signal velocity
• Return path management
•  Advanced Physical Constraints
• Trace Width
• Differential Pair Advanced Physical Constraints
•  Advanced Spacing Constraints
• Class-to-Class Spacing for Differential Pairs to Differential Pairs Spacing
• Constraint Region
•  Advanced Same Net Spacing Constraints
•  Advanced Manufacturing Constraints
• Design for Fabrication Constraints
• Design for Assembly Constraints
• Design for Test Constraints
•  Advanced 3D Constraints
• Component to Component
• Component to Board
• Component to Rigid-Flex
• Component to Board Edge
•  Advanced Properties
• Electrical Properties
• General Properties
• Route/Vias Keepout Exception
• Component Properties – General
• Component Properties – Thermal
• Component Properties – Swapping
• Component Properties – Reuse
• Pin Properties – General
• Pin Properties – Shapes
• Pin Properties – Manufacturing
•  Advanced DRCs
• Constraint Analysis
• Final Constraint Design Rule Check
• Board Simulation (Impedance and Crosstalk Analysis Using Sigrity X Aurora)
• Impedance Workflow
• Coupling Analysis for Crosstalk
• Conclusion of Part 5 - Project Example
• Conclusion - Next Steps
• Appendix