What this 8-position SMT header does in a board-to-wire link
The 3-647166-8: This is an 8-position, single-row header from the MTA-100 series, pitched at 0.100" (2.54mm) — the standard spacing for discrete wire-to-board connections on a 0.062" PCB. It terminates by surface mount, which saves the through-hole step and lets the board run through reflow with the rest of the SMD parts. The friction lock keeps the mating housing from backing off under vibration or cable tug, but the single-wall shroud means the header only guides the plug from one side — alignment relies on the housing's own chamfer.
Pitch, position count, and the surface-mount trade-off
At 0.100" pitch and 8 positions, this header fits a standard 0.8" board footprint. The SMT tails are tin-plated, which is fine for one-off reflow but not for repeated high-temp cycles — the tin reflows at soldering and doesn't hold up to multiple rework passes like gold does. Compare with the through-hole right-angle 1-1871673-2: that part uses a 4-wall shroud and board lock for stronger mechanical retention, but it's a 4-position dual-row at 0.098" pitch — a different footprint and a different assembly process. The 3-647166-8 stays in the same MTA-100 family but trades mechanical robustness for SMT convenience.
The lifecycle status is Active. ROHS3 compliant.