SFM-139-L2-STL-D-A SAMTEC Connector (Other) In Stock
The SAMTEC SFM-139-L2-STL-D-A is a 78-position dual-row high-reliability socket strip with 0.050 inch (1.27 mm) pitch for surface-mount board-to-board interconnect applications. It offers enhanced contact retention and gold-plated dual-beam contacts for stable, low-resistance mating in demanding environments. Available from global distributors in volume and prototype quantities.
- Manufacturer
- SAMTEC
- Package
- Other
- Pin Count
- 78
- Lifecycle
- ACTIVE
- Datasheet
- SFM-139-L2-STL-D-A Datasheet PDF
- Category
- Connector
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
Key Features
- 78-position dual-row high-reliability socket on 0.050 inch (1.27 mm) pitch for compact, high-density board-to-board interconnects
- Gold-plated dual-beam contacts provide low contact resistance and reliable electrical performance over many mating cycles
- Surface-mount termination enables automated reflow assembly and reduces PCB through-hole drilling requirements
- STL (surface-mount long tail) lead style increases solder joint strength for vibration-prone industrial and aerospace applications
Applications
The SFM-139-L2-STL-D-A is used in FPGA mezzanine card stacking, rugged industrial module interconnects, and aerospace daughter-card assemblies where 78 high-reliability signal connections are required in a minimal PCB footprint. Its 0.050 inch pitch and dual-row layout reduce connector length by half compared to single-row alternatives at the same pitch, helping designers meet tight board space constraints. The STL long tail variant is preferred in applications subject to vibration or mechanical stress where solder joint robustness is critical.
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
Alternate & Equivalent Parts
No known alternates. Submit an RFQ and our team can suggest alternatives.
Frequently Asked Questions
How many contacts does the SFM-139-L2-STL-D-A provide and how are they arranged?
The SFM-139-L2-STL-D-A provides 78 contacts in a dual-row configuration on 0.050 inch (1.27 mm) pitch, with 39 contacts per row. This fine pitch and dual-row layout deliver high signal density while keeping the connector footprint compact for space-constrained PCBs used in FPGA mezzanine and module applications.
What makes the STL lead style of the SFM-139-L2-STL-D-A advantageous in vibration-prone applications?
The STL (surface-mount long tail) termination provides an extended solder tail that increases the solder fillet area and joint strength compared to standard surface-mount leads. In applications with mechanical vibration, shock, or thermal cycling — such as aerospace avionics and industrial machinery — longer tails reduce solder joint fatigue and improve long-term reliability across all 78 positions.
Which SAMTEC header series mates with the SFM-139-L2-STL-D-A socket strip?
The SFM-139-L2-STL-D-A is designed to mate with SAMTEC TSM and TSW dual-row male header strips sharing the 0.050 inch pitch. Selecting a TSM or TSW header with a matched stack height creates a precise board-to-board connection with gold-on-gold contact interface, ensuring low-resistance mating across all 78 positions in high-cycle assemblies.
How does the 0.050 inch pitch of the SFM-139-L2-STL-D-A compare to standard 0.100 inch pitch connectors for PCB space saving?
At 0.050 inch (1.27 mm) pitch versus the standard 0.100 inch (2.54 mm) pitch, the SFM-139-L2-STL-D-A occupies roughly half the PCB footprint length for the same pin count. For a 78-position dual-row connector, this translates to approximately 49 mm of connector length at 0.050 inch pitch compared to about 98 mm at 0.100 inch pitch, freeing significant board space for other circuitry.
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