Embedded-cHow-ToBeginner · 4 min read

How to Use Autorouter in PCB Design: Step-by-Step Guide

To use autorouter in PCB design, first prepare your schematic and place all components on the board. Then, launch the autorouter tool in your PCB software, configure routing settings like layers and trace widths, and start the routing process to automatically connect all nets.

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Syntax

The basic steps to use autorouter in PCB design software are:

Prepare schematic: Complete your circuit schematic with all components and connections.
Place components: Arrange components on the PCB layout area.
Configure autorouter: Open the autorouter tool and set parameters such as routing layers, trace widths, and clearance rules.
Run autorouter: Start the autorouting process to automatically route all nets.
Review and adjust: Inspect the routed board and manually fix any issues if needed.

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Autorouter Usage Pattern:

1. Prepare schematic and netlist
2. Place components on PCB
3. Open autorouter tool
4. Set routing parameters (layers, widths, clearances)
5. Run autorouter
6. Review and manually adjust if needed

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Example

This example shows how to use the autorouter in a common PCB design tool like KiCad:

Complete your schematic and generate the netlist.
Import the netlist into the PCB layout editor.
Place all components on the board.
Open the Route menu and select Autorouter.
Set routing layers to 2 (top and bottom), trace width to 0.25 mm, and clearance to 0.2 mm.
Click Start to run the autorouter.
After routing finishes, inspect the traces and fix any errors manually.

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Step-by-step KiCad autorouter commands:

1. Open PCB Editor
2. Import netlist: File > Import > Netlist
3. Place components manually
4. Open Autorouter: Route > Autorouter
5. Configure settings:
   - Layers: 2
   - Trace width: 0.25 mm
   - Clearance: 0.2 mm
6. Click Start
7. Review routed board

Output

Board with all nets automatically routed on top and bottom layers with specified trace widths and clearances.

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Common Pitfalls

Common mistakes when using autorouter include:

Not placing components properly before routing, causing inefficient or failed routes.
Ignoring design rules like trace width and clearance, leading to electrical shorts or manufacturing issues.
Running autorouter without setting correct layer usage, resulting in incomplete routing.
Over-relying on autorouter and not reviewing the results, missing critical routing errors.

Always manually inspect and adjust the routed board after autorouting.

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Wrong way:

// Run autorouter without placing components
RunAutorouter()

Right way:

PlaceComponents()
ConfigureAutorouter()
RunAutorouter()
ReviewAndFix()

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Quick Reference

Step	Description
Prepare schematic	Complete circuit design and generate netlist
Place components	Arrange parts on PCB layout area
Configure autorouter	Set layers, trace widths, clearances
Run autorouter	Automatically route all nets
Review results	Check and fix routing manually

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Key Takeaways

Always place components carefully before running the autorouter.

Set correct routing parameters like layers, trace width, and clearance.

Review autorouter results and manually fix any routing issues.

Autorouter speeds up PCB routing but does not replace manual inspection.

Use autorouter settings that match your PCB manufacturing requirements.