The Hirose DF40C-34DS-0.4V(51) is a 34-position receptacle from the DF40 series, designed for board-to-board mezzanine stacking.
Pitch and Footprint — The Board Layout Constraint
At this pitch, trace escape between pads requires fine-line routing — typically 0.10mm to 0.12mm traces with 0.10mm clearance — and micro-vias or laser-drilled vias under the component. The 1.5mm stacking height sets the z-axis budget: the opposing board must sit exactly 1.5mm above the host board, with no taller components in the keep-out zone under the mezzanine pair.
Contact Plating and Signal Duty
Gold contact finish at 2.00µin thickness is a signal-grade plating. It provides a stable, low-resistance interface for repeated mating cycles in low-current signal paths — think data lines, control signals, or low-power I/O. This is not a power-contact plating; the thin gold layer is optimised for corrosion resistance and cycle life, not bulk current transfer. For a 34-position connector at this pitch, the current per contact will be derated well below what a thicker gold or tin plating would carry in a larger format.
Comparing the (51) and (58) Suffix Variants
The DF40C-34DS-0.4V(58) is electrically and mechanically identical to the (51) variant — same pitch, same 34 positions, same 1.5mm stacking height, same gold plating. The only difference is packaging: the (51) ships in Tape & Reel and Cut Tape, while the (58) adds Digi-Reel as an option. For the board layout engineer or the sourcing desk, there is no design decision between them — the choice is purely a procurement preference based on reel quantity and reel type.