Mezzanine Stacking with a Hybrid Signal-Power Layout
The Hirose FunctionMax FX23L-20S-0.5SV(20) is a 24-position receptacle with a split contact arrangement — 20 signal contacts plus 4 dedicated power contacts — on a 0.50mm pitch in two rows. It mates with the matching FX23L series header (outer shroud contacts) to form a board-to-board mezzanine stack at a 5.80mm mated height. The hybrid contact set lets a single connector carry both low-current signal lines and a moderate power rail, reducing the connector count on densely populated mezzanine boards. Surface-mount termination and integrated board guide and pick-and-place features make this part suited for automated SMT assembly lines. The gold-plated contacts (4.00µin) provide a corrosion-resistant mating interface for moderate-cycle applications in controlled environments.
The dual-row layout doubles the contact density at the board edge, but the fan-out on inner rows requires a via-in-pad or a short dog-leg trace to an inner layer. The 4 power contacts (positions 21–24) are typically assigned to a single voltage rail or a return path. Their current capacity is higher than the signal contacts due to wider contact beams, but the 0.50mm pitch still limits the total power per contact compared to a dedicated power connector. Plan the power trace width from the pad to the plane accordingly.