The Hirose FX30B-2P-3.81DSA20 is a 2-position, single-row male header from the FunctionMax™ FX30B series, designed for board-to-board stacking applications. It carries a 3.81 mm pitch, rated 16 A per circuit at 250 V, with a mated stack height of 20 mm.
16 A per circuit on a 2-position header means each blade carries bus-level current — sized for a power rail, not a signal line. The 3.81 mm pitch gives enough creepage for the 250 V rating without forcing an oversized board footprint. Gold plating on the mating side (3.90 µ" thick) handles repeated mating cycles in a corrosive environment; the tin-plated posts (39.4 µ") are standard for soldering into the PCB.
Board layout and assembly
The through-hole posts are 3.30 mm long, suitable for standard PCB thicknesses. The 20 mm mated stack height is the z-height budget between the two boards; the header sits on one board and mates with a receptacle on the other, with the 14.20 mm insulation height of the header accounting for most of that stack.