The 1.27mm Female Header Dual Row SMT Type Bottom Entry is a specialized surface-mount female socket connector designed for applications requiring vertical board-to-board stacking or dual-sided mating capability. As a "Female Header" (or receptacle), this component features precisely arranged female contacts within an insulator housing, designed to receive male pins from a mating pin header connector. The defining characteristic of this specific variant is its Bottom Entry (also known as Dual Entry) design, which allows male pins to be inserted from the bottom side (solder side) of the connector, in addition to the traditional top-side insertion. This unique feature enables the connector to be mounted on the edge of a PCB while accommodating pin headers from either direction, making it particularly valuable for vertical board stacking applications, mezzanine card configurations, and compact electronic systems where two PCBs must be connected in a parallel, spaced arrangement. The bottom entry design also supports "daisy-chaining" multiple boards or creating modular, expandable systems where connection access from both sides of the PCB is required. When a connector supports both top and bottom insertion, it is often referred to as a Dual Entry or Top and Bottom Entry female header.
The 1.27mm Female Header features a Dual Row contact configuration, with two parallel rows of female contacts providing twice the signal density of a single-row design within the same board footprint. The contacts are spaced at a standard 1.27mm (0.050") pitch, which is half the size of traditional 2.54mm (0.100") spacing, allowing for significant PCB space savings while maintaining reliable signal integrity for compact electronic designs. The SMT (Surface Mount Technology) termination style features flat or slightly formed solder tails designed to be placed directly onto PCB surface pads and secured through reflow soldering, supporting high-speed automated assembly using pick-and-place machines. The connector is typically available in a Vertical (Straight) orientation, with the mating interface parallel to the PCB surface, allowing male pin headers to be inserted perpendicularly from either the top or bottom side. The insulator housing is molded from high-temperature thermoplastics such as PA6T (Polyamide 6T) or LCP (Liquid Crystal Polymer) with 30% glass fiber reinforcement, both rated UL94 V-0 for flame retardancy, capable of withstanding peak reflow temperatures up to 260°C for 10 seconds without deformation. The insulator height (H) is a critical dimension for this connector type, with common heights including 2.20mm (low profile), 4.30mm (standard), and 5.75mm (tall), selected based on the required mating clearance and stacking height in the final assembly.
The 1.27mm Dual Row Bottom Entry Female Header delivers robust electrical performance suitable for a wide range of industrial, consumer, and telecommunications applications. Electrical characteristics typically include a current rating of 1.0 to 1.75 Amperes per contact, a contact resistance of 20 milliohms maximum, an insulation resistance of 1000 megohms minimum, and a dielectric withstand voltage of 500V AC for one minute. The wide operating temperature range spans from -40°C to +125°C, enabling reliable deployment in harsh industrial environments, outdoor telecommunications equipment, and automotive electronics. The female contacts are fabricated from phosphor bronze or brass—copper alloys offering excellent electrical conductivity, spring properties, and mechanical strength—with selective gold plating over a nickel underplating on the mating area to ensure low contact resistance, corrosion protection, and durability through multiple mating cycles. The termination area (SMT solder tails) is typically tin-plated for optimal solderability during the reflow process. Many manufacturers, such as TE Connectivity with their Micro-MaTch series, incorporate additional spring features into the contact design to compensate for thermal expansion differences between the connector housing and the PCB, preventing solder joint stress and ensuring long-term reliability under temperature cycling conditions.
The 1.27mm Female Header Dual Row SMT Bottom Entry is widely deployed in applications requiring compact, high-density board stacking or dual-sided connection access. Primary application areas include vertical board-to-board stacking where two PCBs must be connected in parallel with a controlled spacing, such as in mezzanine card architectures, memory modules, and compact embedded systems; wearable electronics and portable medical devices where space constraints demand low-profile, high-density interconnects; industrial control systems including PLC I/O modules and industrial computers requiring modular, expandable architectures; telecommunications equipment such as routers, switches, and base station line cards; test and measurement instruments requiring flexible connectivity; and consumer electronics including smart home devices and compact audio equipment. Major manufacturers of this connector type include ANTENK (FHCM13 and FHCM07 series), E-tec Interconnect (BS2 series), TE Connectivity (Micro-MaTch series), Samtec (FLE series), and Fullglory (FM-12SV2 series). The connector is typically available in pin counts ranging from 4 to 100 positions (2x2 through 2x50), with common configurations including 2x5 (10P), 2x10 (20P), 2x13 (26P), 2x20 (40P), and 2x25 (50P). In summary, the 1.27mm Female Header Dual Row SMT Bottom Entry is a versatile, space-efficient interconnect solution that uniquely combines high-density dual-row contacts, surface-mount manufacturing compatibility, and bottom/dual entry capability, making it an ideal choice for vertical board stacking, modular system designs, and any application requiring reliable, double-sided connection access in compact electronic assemblies.
