0.40mm Pitch Mezzanine Receptacle for Tight Stack Heights
The Hirose DF40HC(3.0)-50DS-0.4V(51) is a 50-position receptacle from the DF40 series, designed for board-to-board mezzanine stacking. It uses a 0.016" (0.40mm) pitch in a 2-row, center strip contact layout — the tight pitch keeps the board footprint compact, but it also sets the trace/space rules for the PCB layout: you need a fabricator capable of routing between 0.40mm-pitch pads. The connector is surface-mount only, so it feeds the pick-and-place line from Tape & Reel packaging without a secondary through-hole step. The mated stacking height is 3mm, with the receptacle sitting 0.114" (2.90mm) above the board. That 3mm gap is the z-height budget for the mezzanine pair — the matching plug (DF40 series header, same pitch) brings the total stack to exactly 3mm. For a board-stacking engineer, this means the connector defines the board-to-board spacing; no standoffs or additional hardware needed if the mating header is the correct height variant.
Gold Flash Plating — Fixed-Stack Duty, Not Field-Service
The contacts are gold-plated, with a contact finish thickness of 2.00µin (0.051µm).
The DF40HC(3.0)-50DS-0.4V(51) shares its 0.40mm pitch, 2-row layout, 3mm stacking height, and gold contact finish with the 44-position DF40HC(3.0)-44DS-0.4V(51) and the 60-position DF40HC(3.0)-60DS-0.4V(51). If your BOM calls for 50 signal lines, this is the exact match; if you need fewer or more, the 44- and 60-position siblings use the same pad pitch and stack height, so the layout rules carry over.