2.54 mm Pitch Castellated Module Footprint and DFM Guide

2.54 mm-pitch castellated module edge is a module edge package used for board edge assembly, also seen labeled 0.1-inch castellations, hand-solderable half-hole module. A dependable footprint follows the exact orderable-device drawing rather than the family name: nominal body Defined by daughterboard outline, overall span Includes module overhang and component envelope, seated height Module thickness plus fitted components, pitch 2.54 mm, pin count Variable edge-pad count, and exposed pad Large plated half holes.

Use the actual module's half-hole diameter, edge location, and body outline; pitch alone only aids grid compatibility.

Typical uses include prototype modules, breadboard-friendly daughterboards, hand-built controllers. 2.54 mm pitch improves prototyping compatibility but does not define castellated-hole manufacture or module mechanics.

• The 2.54 mm pitch provides generous side-fillet visibility and hand access, but hole breakout and parent-pad length still determine joint strength.
• Castellations are a board-to-board interconnect process, not just half pads drawn on an outline; pitch, edge plating, hole breakout, and module thickness must be agreed with the fab.

Leave toe lands visible outside the module, mark pin functions clearly, and reserve space for a soldering iron without sacrificing nearby connector access.

• Keep the parent-board lands accessible for side fillets, route module signals inward, and preserve antenna, component, and enclosure keepouts beyond the module body.

Hand assembly is rated easy. Hand solder with flux or stencil reflow. Watch for oversized solder blobs, misaligned module, and assuming ordinary routed holes are castellated.

• Confirm edge plating and router path, avoid panel tabs through half holes, and use fiducials if modules will be placed automatically.
• Confirm castellated-hole diameter, minimum pitch, routing method, and whether burr removal or edge copper is included in the quoted service.
• Panelize so routed edges are supported without tabs crossing the plated half holes, and add fiducials suitable for module placement.

Inspection focus:

• Inspect every side fillet and module alignment, then continuity-test each edge pin and perform a mechanical push check appropriate to use.
• Inspect every side fillet, module coplanarity, edge burrs, and solder bridges; then test each interface because a visually small void can open a castellation.

Common mistakes:

• Flooding large parent lands with hand solder can bridge beneath the daughterboard where the short is difficult to see or remove.
• Do not place ordinary plated holes on Edge.Cuts and assume every fabricator will turn them into clean castellations automatically.

1. Before approving 2.54 mm-pitch castellated module edge, compare the exact orderable-device drawing with the library item: body range (Defined by daughterboard outline), terminal or lead span (Includes module overhang and component envelope), pitch (2.54 mm), pin count (Variable edge-pad count), height (Module thickness plus fitted components), and exposed-pad definition (Large plated half holes). Record the source drawing revision and every intentional courtyard, toe, heel, side, mask, or paste adjustment.
2. Treat the easy hand-solder rating as a prototype-planning input, not proof of production yield. Review oversized solder blobs, misaligned module, and assuming ordinary routed holes are castellated with the assembler, confirm that hand solder with flux or stencil reflow is compatible with the build, and require the S1 connectivity gate plus relevant S2 geometry checks to pass against the released footprint and selected fabrication profile.

Manufacturing gate checks:

1. S1Pad count, numbering, and schematic parity. Castellation manufacturing note, routed edge, hole breakout, pad overlap, pin map, and full module courtyard require checks.
2. S1Castellated-hole breakout and edge geometry. The routed outline must bisect the plated holes as intended without leaving an ambiguous or unmanufacturable board edge.
3. S2Courtyard and body clearance. The body, leads, placement tolerance, rework access, and nearby height limits all belong in the manufacturing review.