40-Position Mezzanine Header with 3.5mm Stack Height
The Hirose DF12NB(3.5)-40DP-0.5V(51) is a 40-position header from the DF12 series, designed for board-to-board mezzanine stacking. Gold-plated contacts with 8.00µin thickness on the mating surface support repeated connection cycles in signal-level applications.
What the 3.5mm Stack Height Means for Your Board Stack-Up
This is the fixed board-to-board gap when the pair is mated. The height above board of this header alone is 0.110" (2.80mm) — that's the profile the header stands off the PCB before the receptacle is mated. For comparison, the DF12NB(3.0)-40DP-0.5V(51) provides a 2.30mm height above board and mates to a 3.0mm stack — a 0.5mm difference that can matter when routing traces under the connector or fitting into a tight enclosure.
This 40-position header shares the same 0.50mm pitch, dual-row layout, and 3.5mm stack height with the 36-position DF12NB(3.5)-36DP-0.5V(51) and the 50-position DF12NB(3.5)-50DP-0.5V(51). All three use the same 8.00µin gold plating and outer shroud contact design, so the signal integrity and cycle life are consistent across the range.
Surface Mount Assembly and Solder Retention
This header is surface mount only — no through-hole posts. In a mezzanine stack, the connector pair takes shear loads from board handling and vibration; the retention tabs help keep the header from lifting off the pad over temperature cycles.