40-pin mezzanine header with a 3mm gap
The DF12B(3.0)-40DP-0.5V(86) is a 40-position header from the Hirose DF12 series, pitched at 0.50mm across two rows. It mates to a stacking height of 3mm — the gap between boards is fixed by the connector body, not adjustable. The outer shroud contacts and solder retention features help keep the connector seated during reflow and in service, but the 0.50mm pitch leaves little room for misalignment — the board-to-board float is tight.
Obsolete — plan for an alternative
Hirose has marked this part as Obsolete. For a new design, look at the active DF12 series variants — the pitch and stacking height are the same, but confirm the position count and contact finish.
Gold finish and surface-mount termination
The surface-mount tails suit a standard reflow profile.