The Amphenol FCI 10039851-101LF is a 54-position right-angle header from the Airmax VS® series, designed as a high-speed daughtercard connector. It uses a 9-row by 6-column grid on a 1.40mm pitch, with all positions loaded. The contact layout is arranged as 18 differential pairs with 18 ground pins — a pinout that keeps each signal pair referenced to an adjacent ground return, which matters for controlled-impedance routing through the backplane. Termination is press-fit, which means the compliant pin displaces the plated-through hole wall rather than relying on solder. That makes this header suited for solderless backplane assembly where rework access is limited and the board sees multiple reflow passes for other components.
The mating interface carries 30.0µin gold over the base metal. In a backplane context where the daughtercard may be swapped during field service, the gold preserves contact resistance through those cycles.
Board mounting and assembly considerations
Mounting is board-edge, through-hole, right-angle. The press-fit tail requires a specific PCB hole diameter and plated-through-hole wall thickness to achieve the correct interference fit — the datasheet drawing gives the finished hole size and the recommended pad pattern. The 1.40mm pitch is fine enough to route differential pairs between columns on a standard backplane layer stack, but the 9-row depth means the connector footprint extends about 12.6mm from the board edge, so the keep-out zone on the daughtercard needs to account for that.