0.50mm Pitch Mezzanine Header, 40 Positions, Dual-Row SMT
The Hirose DF17B(4.0)-40DP-0.5V(57) is a 40-position header from the DF17 series, designed for board-to-board mezzanine stacking. The mated stacking heights are 7mm and 8mm, which sets the board spacing in a mezzanine pair.
At 0.50mm pitch, trace escape from the inner rows requires via-in-pad or micro-via routing on dense boards — standard through-hole vias between pads won't fit. The 0.248" (6.30mm) height above board, combined with the 7mm or 8mm mated stack height, defines the z-axis clearance between stacked PCBs. The outer shroud contacts provide some alignment during mating, but the tight pitch means the board-to-board alignment tolerance needs to be held close during assembly.