Board-Stacking Selection: 0.4mm Pitch, 40 Positions, 0.8mm Mated Height
The Hirose BM10B(0.8)-40DP-0.4V(51) is a 40-position header with outer shroud contacts from the BM10 series, designed for board-to-board mezzanine stacking at a mated height of 0.8mm. Its 0.016" (0.40mm) pitch and dual-row layout pack 40 signal paths into a compact footprint suited for space-constrained portable electronics, handheld devices, and LCD panel interconnects. The header stands 0.025" (0.63mm) above the board after reflow, and the solder retention feature holds the part in place during SMT assembly and resists shear from the mating receptacle.
Pitch, Profile, and Contact Plating
At 0.40mm pitch, the trace routing between pads is tight — expect 0.2mm trace and space on standard PCB fabrication limits. The 0.63mm above-board height combined with the 0.8mm mated stack height means the mating receptacle sits just 0.17mm above the header body, leaving minimal z-height clearance. Gold contact finish at 2.00µin thickness is a flash plating — adequate for a few mating cycles during manufacturing and test, but not rated for repeated field disconnect. The outer shroud contact design mates with a corresponding BM10 receptacle that has contacts on the outer shell, not a conventional female socket.
Position Count Comparison Within the BM10 Series
The 40-position BM10B(0.8)-40DP-0.4V(51) is the highest circuit-count member in the BM10 series that shares the same 0.40mm pitch, 0.63mm above-board height, and gold flash plating. The 34-position BM10B(0.8)-34DP-0.4V(51) and 30-position BM10B(0.8)-30DP-0.4V(51) are identical in every other dimension — the only difference is the number of signal paths.