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X AI Product Guide

Setup: Recommended Design Inputs

It is recommended to define the following inputs in the PCB canvas to improve results and/or reduce run time:

  • Preconfigure fanouts
  • Preplace high-speed via structures
  • Complete copper pours
  • Minimize static shape usage
  • Define region-based constraints

Preconfigure Fanouts for Large Components

Location: PCB Canvas

Fanouts Step8

It is recommended to pre-fanout large pin count devices to ensure intended via usage or consider constraint regions. These should be locked in the design and/or included in the PCB footprint for reuse across multiple designs.

Preplace High-Speed Via Structures

Location: PCB Canvas

High-speed via structures should be pre-placed on the PCB to ensure accuracy.

Complete Copper Pouring

Location: PCB Canvas

The majority of power and ground shapes should be added before routing. These should be added as dynamic shapes to allow Allegro X AI to route within or across a dynamic shape but at a high cost if alternative solutions cannot be found.

Recommendations:

It is important to define voltage shapes on conductor layers.

Minimize Static Shapes

Location: PCB Canvas

Overuse of static shapes may impact the router quality of return as shapes are seen as a keep out area. Convert static shapes to dynamic shapes where appropriate. Allegro X AI will not attempt to connect or tee into a static shape.

Recommendations:

Try not to overload the design with static shapes

Use static shapes only for low pin count voltage nets not to be compromised with routes or vias.

Define Region-Based Constraints

Location: PCB Canvas

RegionRules Step26

Define regions for BGAs and other high pin density devices where reduced line width and spacing is required. Keep region-based constraints simple and avoid overlap if possible. The X AI router will respect region-based rules for line width, spacing, and via usage.

Recommendations:

Configure region-based rules for devices that require non-default vias. Remember to enable the via list DRC.

Keep region-based constraints simple and avoid overlap.

Need Help? Get step-by-step instructions for creating and managing region-based constraints in OrCAD X Presto here.  

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