SOD-323 PCB Footprint: Dimensions, Polarity, and DFM Guide

SOD-323 is a chip component package used for surface mount assembly, also seen labeled SC-76, small-outline diode 323, SOD323. A dependable footprint follows the exact orderable-device drawing rather than the family name: nominal body About 2.5 × 1.25 mm, overall span Typically 2.3–2.7 mm long, seated height Often 0.9–1.1 mm, pitch Two end terminals; no lead pitch, pin count 2, polarized, and exposed pad None.

Use the exact SOD-323/SC-76 drawing and cathode convention; termination length varies by supplier.

Typical uses include ESD steering, small signal diodes, low-current Schottky rectifiers. SOD-323/SC-76 outlines are similar across vendors, but exact body, terminal, and marking data remain part-specific.

• SOD-323 reduces area from SOD-123 while retaining exposed end joints, but its small molded polarity mark may be difficult to inspect.
• A two-terminal size code describes an envelope, not universal termination length, height, polarity, power, or voltage capability.

Put ESD devices directly at the entry point with a short return and keep both pads thermally balanced to prevent skew.

• Keep copper and thermal mass reasonably balanced at both ends, and move vias outside the paste-bearing land unless the assembly process is designed for via-in-pad.

Hand assembly is rated moderate. Stencil reflow or microscope-assisted fine-tip soldering. Watch for tiny cathode marks, tombstoning, and accidental sod-523 substitution.

• Confirm mask web, paste registration, and AOI polarity recognition on the selected top marking.
• Select the stencil aperture with the assembler; copper, mask, and paste openings solve different process problems.
• Keep brittle ceramic bodies away from panel break lines, mounting hardware, and enclosure features that bend the finished PCB.

Inspection focus:

• Inspect both side fillets under magnification and validate diode orientation electrically because body markings can be subtle.
• Compare the two visible end fillets for wetting, skew, and solder volume, then use electrical test for failures such as cracked ceramics that AOI cannot see.

Common mistakes:

• Moving the ESD diode inward to make routing prettier increases the unprotected trace length and surge-loop inductance.
• Do not substitute a resistor, capacitor, LED, fuse, ferrite, or shunt solely because its nominal body code matches.

1. Before approving SOD-323, compare the exact orderable-device drawing with the library item: body range (About 2.5 × 1.25 mm), terminal or lead span (Typically 2.3–2.7 mm long), pitch (Two end terminals; no lead pitch), pin count (2, polarized), height (Often 0.9–1.1 mm), and exposed-pad definition (None). Record the source drawing revision and every intentional courtyard, toe, heel, side, mask, or paste adjustment.
2. Treat the moderate hand-solder rating as a prototype-planning input, not proof of production yield. Review tiny cathode marks, tombstoning, and accidental sod-523 substitution with the assembler, confirm that stencil reflow or microscope-assisted fine-tip soldering 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. Cathode-to-net mapping, two-pad geometry, body orientation, protection placement, and mask capability require review.
2. S2Solder-mask web and paste geometry. Two close lands still need a process-capable mask dam and a paste plan that will not tombstone the body.
3. S2Courtyard and body clearance. The body, leads, placement tolerance, rework access, and nearby height limits all belong in the manufacturing review.