Board-to-Board Mezzanine Connector for Tight Stack Heights
The Hirose DF40C-50DS-0.4V(51) is a 50-position receptacle from the DF40 series, designed as a center strip contact connector for board-to-board mezzanine stacking. Its defining feature is the 0.016" (0.40mm) pitch across two rows, which packs 50 circuits into a compact footprint suited for space-constrained portable electronics, camera modules, and internal display interconnects where the PCB real estate is at a premium. The mated stacking height is 1.5mm, making this part a fit for thin-profile assemblies where the gap between boards is tight.
What the 0.40mm Pitch and 1.45mm Height Mean for Your Layout
At 0.40mm pitch, the routing density between pads is high — expect trace-and-space limitations on the PCB that may require via-in-pad or microvia fan-out for the inner rows. The 0.057" (1.45mm) height above board sets the z-axis clearance between the two PCBs after mating, so the total stack height of 1.5mm (per the mated spec) governs the enclosure thickness budget. This is not a connector you hand-solder; the surface mount termination demands a reflow profile matched to the gold-plated contacts.
Position Count Choice: 50 vs 40 vs 60
The DF40C family shares the same 0.40mm pitch, 2-row layout, and 1.45mm board height across position counts. The DF40C-50DS-0.4V(51) sits between the 40-position DF40C-40DS-0.4V(51) and the 60-position DF40C-60DS-0.4V(51). The decision is purely a circuit-count match — the footprint grows linearly with positions, so the 50-position version is for a 50-signal BOM line where 40 is too few and 60 wastes board area. The contact finish thickness is identical at 2.00µin across all three, so there is no duty-cycle trade-off.
Mating and Stacking Height Options
This receptacle mates with the corresponding DF40 series header (typically the DF40C-xxDP-0.4V series) to form a 1.5mm mated stack. For applications needing a taller gap, the DF40C(2.0)-50DS-0.4V(51) variant offers a 0.077" (1.95mm) board height, which changes the mated stack to 2.0mm — a direct swap on the same footprint if the z-axis budget allows. The gold-over-nickel contact finish at 2.00µin is standard for the series and supports the moderate mating cycle counts typical of internal board-to-board connections.