PCB Footprint Checks: Catch Package and Pin-Mapping Errors Before Release

A footprint can look convincing on screen and still be wrong for the part you intend to buy. The important check is the relationship between the exact component, its symbol, the copper pads and the surrounding mechanical space. Do that review before the layout becomes expensive to change.

Start with the complete part identity

Use the manufacturer’s complete part number and package drawing. A familiar package family name is not enough to distinguish every body size, pitch or pin arrangement. Record the datasheet revision used for the check so another person can repeat it. If there are multiple package options, identify the one represented by the footprint.

Trace numbers from symbol to pad

Compare the symbol pin numbers with the footprint pad numbers and the manufacturer’s pin assignment. Do not infer numbering only from the visual position of a connector. Also check whether the drawing is a top, bottom or mating-face view. Add a clear pin-one or polarity indication to the assembly documentation where it is needed.

Review the physical land pattern

Compare pad sizes, pitch and overall placement with the applicable land-pattern guidance. Include holes, slots and exposed pads where present. The KiCad Library Convention treats pad numbering, footprint geometry and courtyard information as separate aspects of footprint quality; library membership is still not a substitute for checking the selected part.

Look beyond the solder joints

A connector may fit its pads while colliding with the enclosure or leaving no room for its mating cable. Check component height, insertion direction, latch travel and access for assembly or rework. Review the intended hardware around mounting holes rather than considering only the hole diameter.

A 3D view or a printed placement drawing can help communicate these questions, but neither proves that the electrical numbering or manufacturing dimensions are correct. Keep the drawing and part evidence available with the review notes.

Create a short approval record

• Exact part number and package drawing checked.
• Symbol-to-pad mapping verified, including polarity.
• Land pattern and any special paste requirements reviewed.
• Mechanical envelope and connector access checked.
• Reviewer, date and footprint revision recorded.

When a substitute component is proposed, revisit this record. “Same value” or “similar package” does not by itself establish footprint compatibility. Clear the substitution before it becomes part of the assembly release.

Technical reference: KiCad Library Convention: footprints. Always use the selected component manufacturer’s drawing for the actual part; this checklist does not approve a particular package.