2.54mm Pitch Bottom Entry Female Header Connector Pass Through Socket Dual Row PCB Mount

A conventional female header mates from above, which forces the mating board to sit on top of the host PCB. This bottom entry version reverses the geometry: the contact cage opens downward through a window in the insulator, so a male header can enter from underneath the board. That single change lets a daughter card sit flush against the back of the main board, reducing total assembly thickness by the full body height of the connector.

The pass through design also simplifies rework. Because the pin field is accessible from below, an operator can probe or desolder the joint without lifting the upper board, and the mating header can be a simple turned or stamped male strip with no shroud. The insulator keeps standard 2.54mm spacing and dual row geometry, so the part drops into footprints that were originally laid out for an ordinary top entry socket.

• Bottom entry geometry: The mating post enters from below the PCB, letting the daughter card sit flush against the main board.
• Flush stacking: Removes the body height from the total assembly thickness, which matters in slim enclosures.
• Probe accessible joints: The pin field can be reached from underneath, so rework and inspection do not require lifting the upper board.
• Standard 2.54mm footprint: Drops into land patterns already laid out for a top entry dual row socket.
• Gold flash over nickel: Stable contact resistance with a barrier layer against humidity and industrial sulphur.
• Simple male mating: Accepts plain stamped or turned male strips, so the mating side needs no shroud or keying hardware.

Bottom entry sockets are used wherever the stacking order is fixed by mechanics. Portable instrument enclosures often mount the display board behind the main board, so the electrical connection has to come from behind. Automotive control modules use them to attach a daughter card on the underside of a main PCB inside a shallow housing. They also appear in card readers and access control units where the reader board sits under the controller board, and in test adapters where an operator needs to probe the joint side while the connector is mated.

We can mould the bottom window to accept either 0.64mm square posts or 0.5mm round pins, and can add a locating peg or a mounting flange for panel alignment. Positions from 2 x 2 to 2 x 40 are cut from strip without tooling charges. Optional variants include selective gold at 0.76 micron, a closed top face so flux cannot enter from above, and a matched male header supplied as a pair from the same drawing. Engineering can also advise on solder paste volume for the bottom entry window, which is the most common source of defects in this configuration.

Each connector is packed 1000 pieces per anti-static bag with a desiccant sachet, ten bags per export carton. The bags are cushioned with foam so the contact cage cannot be deformed through the bottom window, which is the most delicate feature of this part. Cartons carry the CNJWY neutral label, stay below 15 kg gross and are sealed with tamper evident tape. Sea freight is palletised and stretch wrapped against container humidity, and air shipments are foam lined. Own-brand cartons, barcode labels and drop tested inner packaging are offered, and each lot ships with a dimensional report, a plating thickness certificate and a RoHS declaration.