Board-to-board mezzanine header for tight z-height stacks
The Hirose BM10B(0.8)-24DP-0.4V(51) is a 24-position header from the BM10 series, designed for board-to-board mezzanine stacking. Contact finish is gold with a thickness of 2.00µin (0.051µm), a flash plating that handles the limited mating cycles typical of a fixed mezzanine interconnect.
Pitch and stacking height drive the board layout
The 0.40mm pitch is fine enough that trace routing between pads requires careful breakout — expect one trace per channel on outer layers, or microvias for inner-layer escape. The 0.8mm mated stack height means the mating receptacle must match this exact dimension; the BM10 series offers other stack heights, but this variant is fixed at 0.8mm. The header stands 0.025" (0.63mm) above the board before mating, which gives a low profile for tight enclosures. Solder retention pads on the sides add mechanical hold without increasing the footprint width beyond the shroud outline.