0.60 mm pitch mezzanine receptacle, 80 positions, 3 mm / 4 mm stack
The Hirose FX8-80S-SV(21) is an 80-position receptacle from the FunctionMax™ FX8 series, built for board-to-board mezzanine stacking at a 0.60 mm pitch. It uses a dual-row center-strip contact layout, with the contacts arranged along the centerline of the connector body rather than along the edges — this keeps the mating interface symmetric and reduces the footprint width for a given position count.
This receptacle supports two mated stacking heights: 3 mm and 4 mm. The height above the PCB is fixed at 2.26 mm for the receptacle itself; the mating plug determines the final stack. On a 0.60 mm pitch, the 80 positions span roughly 24 mm along the board edge, which forces a fine-line routing strategy — two traces between pads on a standard 0.5 oz copper layer are tight but achievable with a 0.10 mm trace/space design rule. The SMT termination and board guide mean the footprint should include alignment fiducials and a solder-paste stencil aperture that matches the Hirose recommended land pattern.