80-Position, 1.27 mm Pitch SMT Header for Board-to-Board Stacking
The 87409-140LF: The 1.27 mm pitch and 6.42 mm mated stack height set the board spacing and routing density — tight enough for compact assemblies but still hand-solderable with a fine tip. The 4-wall shrouded housing with a board guide aligns the mating receptacle during assembly, reducing shear stress on the SMT solder joints. Push-pull fastening means no secondary locking hardware — the connector relies on the shroud friction for retention, adequate for low-vibration environments.
For a signal path that sees quarterly reconnects in a test or calibration fixture, that gold thickness translates to decades of reliable contact resistance below 20 mOhm. In a one-time board assembly, the gold is overkill — but it's what the Rib-Cage III series specifies for this position count.
The 1.27 mm pitch and 0.050" row spacing demand a tight board layout — trace routing between pads is feasible with 0.2 mm trace/space on a standard 2-layer board, but a 4-layer stack-up gives cleaner signal integrity for the 80 circuits. The SMT footprint should match the recommended land pattern from the Rib-Cage III datasheet. Mating half is a Rib-Cage III receptacle (same series) with matching 80 positions, 1.27 mm pitch, and a 6.42 mm mated stack height.