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Avoiding Common PCB Design Mistakes

Printed Circuit Board Design

Verify your Circuit Board Design Files Include an Aperture List

Unless you are using Gerber274X format files, an aperture list is required for the manufacturer to create the artwork needed for your circuit board design.

Gerber274D format does not automatically include Aperture List information.All circuit board design software that can output in Gerber274D format will also output the Aperture List with one of the following common file extensions: .rep, .apt, and .apr.

Missing Drill File

The drill file is used to determine the size and location of each hole (plated or non-plated thru) in the circuit board design. Most PCB layout packages generate this file. Make sure to include it in the output file set provided to the fabricator.

Tool List

The tool list should be embedded in your drill file or can be sent as a separate .txt file. Common tool List extensions are .tol and .rep.

Annular Rings

You must ensure annularrings meet minimum size requirements. Annular rings are the ‘donut” shaped area of the a connecting via or a plated thru hole. There are minimum size requirements for the width of this area. The minimum annular ring should be 0.005″ for vias and 0.007″ for component holes.

Insufficient Copper Trace Width/Spacing

There must be sufficient space between two adjacent copper features to avoid shorts, arcing or fabrication issues. Minimum spacing for manufacturing is generally 0.005″, but varies for different fabricators and may incur a premium charge if less than 0.007.″


Insufficient spacing between the edge of a hole and internal copper may cause shorts or other issues. Generally a minimum of 0.010″ space between the internal copper feature and adjacent drill hole is required, but 0.015″ is preferred.