What This 140-Position Header Does in a Board Stack
The Hirose FX10A-140P/14-SV(91) is a 140-circuit, 2-row header from the FunctionMax™ FX10 series, designed for parallel board-to-board stacking at a 4mm mated height. At a 0.50mm pitch, this is a dense signal interconnect — the 70 contacts per row require a careful PCB fan-out strategy to route traces between the pads. The outer shroud contacts provide mechanical protection during mating and help align the two boards before the pins engage. The board guide and ground plate are integrated features: the guide prevents pin stubbing during blind mating, and the ground plate provides a low-inductance return path that matters for high-speed signal integrity.
Stack Height and Footprint — the Two Dimensions That Decide Fit
The FX10A-140P/14-SV(91) uses a 0.138" (3.50mm) height above board, which means the mating receptacle sits 0.50mm above the header's mounting surface to reach the 4mm total. If your design needs a taller stack, the sibling FX10A-140P/14-SV1(91) delivers a 4.50mm mated height with a 0.177" (4.50mm) board standoff — same 140 positions, same 0.50mm pitch, same footprint, just a different z-height. The choice between them is purely a mechanical clearance decision. For a lower circuit count, the FX10A-120P/12-SV1(91) drops to 120 positions at the same 0.50mm pitch and 4.50mm stack height — useful when the BOM calls for fewer signals but the same board spacing and footprint pattern.
Surface Mount Assembly and Solder Retention
This is a surface-mount header — no through-hole tails, so the board requires no drilled vias for the signal pins. The Tape & Reel packaging (Cut Tape also available) feeds directly into a pick-and-place line, which is the standard assembly method for a 0.50mm-pitch part this dense.