120-Position, 0.053"-Pitch Backplane Receptacle — Impact 76160
The Molex 0761605010 is a 120-position receptacle, female sockets, part of the Impact 76160 series. It is configured as 12 rows by 10 columns, with a 0.053" (1.35 mm) pitch that packs differential pairs at the density needed for high-speed backplane routing. Rated for 40 differential pairs, this is the column count that matches a 10-column header: each column carries four differential pairs, one per row quartet. The 30V voltage rating is typical for backplane signal levels; the real constraint is the signal-integrity budget at 25+ Gbps, not the dielectric withstand. Press-fit termination eliminates solder, which keeps the plated-through holes clean and allows rework without desoldering — a practical advantage on thick, high-layer-count backplanes where thermal mass makes reflow unreliable.
Board Layout and Stack-Up Fit
The 0.053" pitch means the via field is tight — expect a 0.025" finished hole on a 0.039" pad, with a 0.010" annular ring. That leaves about 0.014" between adjacent pads, which limits the number of routing channels between vias to one trace per channel for typical 50-ohm stripline. The Board Guide feature adds a molded alignment post that engages the header before the contacts touch, giving about 0.5 mm of float to correct board-to-board misalignment.