Hirose DF40T Mezzanine Receptacle — 0.40mm Pitch, 40 Positions, 3.5mm Stack
The Hirose DF40TC(3.5)-40DS-0.4V(58) is a 40-position receptacle from the DF40T series, designed for board-to-board mezzanine stacking at a 3.5mm mated height. SMT termination with integrated pick-and-place and solder retention features means this part is set up for automated assembly — no secondary hold-down hardware needed.
Position Count Variant — 40 vs 30 Positions
For a lower circuit count at the same 3.5mm stack height, the DF40TC(3.5)-30DS-0.4V(58) drops to 30 positions while keeping the same 0.016" (0.40mm) pitch and 0.134" (3.40mm) height above board. The footprint length scales with position count, so the board layout must match the BOM line count exactly — no depopulating unused positions on a 40-position part to get 30 circuits.
No official second-source cross-reference exists; the DF40T series is Hirose proprietary, so the mating half must also be a DF40T header.