TSSOP-16 PCB Footprint: Dimensions, DFM, and Assembly Guide

TSSOP-16 is a gull wing package used for surface mount assembly, also seen labeled thin shrink small outline 16, MO-153 variants. A dependable footprint follows the exact orderable-device drawing rather than the family name: nominal body About 5.0 × 4.4 mm, overall span About 6.4 mm lead span, seated height Typically 1.0–1.2 mm, pitch 0.65 mm, pin count 16, and exposed pad None unless explicitly sold as an exposed-pad variant.

Use a body-and-lead-span-specific footprint and model exposed-pad power versions separately.

Typical uses include motor and LED drivers, I/O expanders, mixed-signal ICs. TSSOP-16 and exposed-pad HTSSOP-16 are separate land-pattern decisions even when their perimeter leads align.

• Eight leads per side at 0.65 mm pitch fit substantial I/O into a 5 mm body length, leaving little room for careless trace escape between pads.
• Gull-wing package names cover families of drawings; body width, lead span, lead length, and seated height must all match the orderable part.

Group high-current outputs and quiet inputs according to the pinout; do not run sense or reference traces parallel to switched output copper.

• Route away from the lead toe, preserve visible solder fillets, and keep the pin-one cue unambiguous on copper, silkscreen, and the assembly drawing.

Hand assembly is rated moderate. Stencil reflow; drag soldering is practical with flux and magnification. Watch for bridges and wrong thermal-pad assumptions on power variants.

• Review paste and solder-mask geometry across all sixteen pads and keep copper neckdowns identical where reflow symmetry matters.
• Use symmetric paste apertures and a real component courtyard so placement does not rotate or crowd neighboring parts.
• Do not lengthen every pad for hand soldering on the production footprint; excessive toe extension consumes routing and can increase solder movement.

Inspection focus:

• Inspect corner coplanarity, every toe fillet, and bridges; load-test output channels because an open lead can escape simple idle-current checks.
• All lead toes should be optically accessible. Inspect alignment, heel/toe wetting, bridges, lifted leads, and orientation before functional test.

Common mistakes:

• Using the same footprint for ordinary TSSOP-16 and HTSSOP-16 silently omits the exposed thermal pad required by many drivers.
• Never infer functional pin numbering from another IC in the same mechanical family; verify symbol, footprint, and datasheet together.

1. Before approving TSSOP-16, compare the exact orderable-device drawing with the library item: body range (About 5.0 × 4.4 mm), terminal or lead span (About 6.4 mm lead span), pitch (0.65 mm), pin count (16), height (Typically 1.0–1.2 mm), and exposed-pad definition (None unless explicitly sold as an exposed-pad variant). 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 bridges and wrong thermal-pad assumptions on power variants with the assembler, confirm that stencil reflow; drag soldering is practical with flux and magnification 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. The gate must distinguish TSSOP from HTSSOP and verify the thermal-pad net whenever the selected MPN includes one.
2. S2Lead-to-pad alignment and solder-mask web. Pitch, toe extension, and mask slivers must fit the selected assembly capability without hiding a lead.
3. S2Courtyard and body clearance. The body, leads, placement tolerance, rework access, and nearby height limits all belong in the manufacturing review.