An alternate component with a different footprint is more than a BOM substitution. The common board may need both land patterns, and their geometry must coexist without creating unintended connections or assembly ambiguity. Review the bare-board result separately from the selected fitted part.
Altium’s design variant documentation describes how alternate parts with different footprint names can transfer both footprints to the PCB. It also specifies compatibility requirements for alternate schematic pins. Tool support for a variant does not establish that the resulting physical arrangement is suitable.
Define the variant relationship
List the base component and each alternate, their package drawings, pin mappings, and intended fitted states. State whether every variant truly shares one bare board. If copper or other fabrication layers must differ, control those fabricated configurations explicitly rather than presenting them as simple population options.
Inspect the combined land patterns in the PCB. Follow every terminal to its intended net, including pads belonging to the unfitted alternative. Confirm that overlapping or nearby copper does not create a connection that is valid for one package but wrong for another.
Check each physical configuration
| Area | Review question |
|---|---|
| Copper and drilling | Can all intended variants use the same fabricated geometry? |
| Component bodies | Does each fitted package clear its neighbors? |
| Mask and paste | Are the openings appropriate for the selected assembly? |
| Assembly documentation | Is the fitted alternative unambiguous? |
Use the actual package dimensions and mounting recommendations for each alternative. Similar pin counts do not establish body clearance, thermal-pad compatibility, or an acceptable soldering process. Capture any variant-specific assembly instruction in the released documentation. Include the selected model in mechanical clearance checks when the alternatives have different body heights.
Generate and reconcile outputs by variant
- Select the intended variant explicitly.
- Generate its BOM, placement data, and assembly drawing.
- Check that only the authorized alternative is populated.
- Review relevant paste outputs and process requirements.
- Confirm the common fabrication package remains the intended one.
Where alternate footprints share a logical designator, verify how downstream software imports them. The assembler should not receive two unexplained placement rows for one fitted position or silently choose a footprint based on file order. Resolve the representation before production setup.
Keep an example output set for every released variant. A base-design review does not prove that all alternate documentation is correct. The variant paste review provides a complementary check for deposition data, while this review establishes that each fitted alternative remains compatible with the shared board.
Move from reading to a build-ready project
Use the fabrication and assembly checklists to prepare drawings, production files and test requirements.
Open the DFM checklist