MMS-116-02-LM-SV

FAQFrequently Asked Questions

• What are the key design considerations when integrating the MMS-116-02-LM-SV receptacle into a board-to-board connector stack? The MMS-116-02-LM-SV is a 16-position surface-mount receptacle with 0.079" (2.00mm) pitch and 0.177" (4.50mm) insulation height. When designing the mating interface, account for the push-pull fastening mechanism, which requires adequate PCB real estate for operator access during connection and disconnection cycles. The 3.9A per-contact current rating means total system current should not exceed approximately 62A if all 16 contacts are fully loaded. Verify that your mating connector (typically a MMS-116 plug series) has compatible pitch and row spacing. The solder termination requires reflow profile compatibility with your manufacturing process, and the LCP insulation material performs reliably across -55°C to 125°C, making it suitable for industrial temperature ranges. Plan for thermal management if contacts will consistently operate near the 3.9A per-contact maximum.
• Can the MMS-116-02-LM-SV replace other 2.00mm pitch board-to-board connectors from competing manufacturers? The MMS-116-02-LM-SV uses Samtec's MMS series geometry with 0.079" (2.00mm) pitch. Direct mechanical and electrical compatibility depends on whether your existing connector also uses 0.079" pitch with identical row spacing and push-pull locking mechanism. Common competitors like Molex (Micro-Fit series) or TE Connectivity offer similar pitch connectors, but the MMS-116-02-LM-SV has specific contact geometry (square cross-section phosphor bronze), mating force characteristics, and stacking height (0.177" insulation height) that may differ. Before migrating to the MMS-116-02-LM-SV, verify that your PCB layout, assembly fixturing, and mating connector part numbers are compatible with Samtec's MMS geometry. The gold mating contact finish (10.0µin thickness) provides superior wear resistance compared to some tin-only alternatives, which can reduce fretting corrosion in frequent mating cycles.
• How does the gold plating thickness on the MMS-116-02-LM-SV mating contacts affect long-term reliability in high-cycle insertion applications? The MMS-116-02-LM-SV features 10.0µin (0.25µm) gold plating on the mating contacts, which is a thin but functional finish for moderate-cycle applications. This thickness provides initial low contact resistance and protects the underlying phosphor bronze from corrosion during storage and early mating cycles. However, in applications exceeding 1,000 insertion cycles or operating in corrosive environments (high humidity, salt spray), the thin gold layer will wear through in localized contact areas, exposing the phosphor bronze substrate. This transition typically increases contact resistance slightly but remains acceptable for signal and low-power applications. If your application requires more than 5,000 mating cycles in harsh environments, consider specifying a thicker gold plating or a nickel underplate to extend contact life. The tin finish on the solder posts (signal-side termination) remains stable and does not affect mating cycle performance.
• What are the PCB layout implications for the MMS-116-02-LM-SV in high-speed differential signal applications? The MMS-116-02-LM-SV is a rectangular connector with 16 individual contacts arranged in a single row at 0.079" (2.00mm) pitch. For high-speed applications (MHz to low GHz), the single-row geometry presents several design trade-offs. First, all 16 contacts share the same via field directly beneath the connector footprint, which can create crosstalk and impedance discontinuities if not carefully managed. Route differential pairs with equal lengths and controlled spacing; the close 2.00mm pitch limits physical separation, so consider using internal PCB layers to isolate signal pairs. Second, the connector's ground plane proximity affects impedance: verify that your stackup and ground vias provide low-inductance return paths for each contact. Third, the push-pull mating mechanism and LCP insulation create a relatively compact footprint but offer limited shielding between adjacent contacts. For applications requiring better signal isolation (e.g., mixed-signal or RF), evaluate whether a shielded variant or multiple smaller connectors would better meet your crosstalk budget. The MMS-116-02-LM-SV performs well for digital logic and moderate-frequency analog signals where contact-to-contact crosstalk is not a primary concern.
• Is the MMS-116-02-LM-SV suitable for unmated storage in humid or salt-spray industrial environments? The MMS-116-02-LM-SV carries a Moisture Sensitivity Level (MSL) of 1, indicating unlimited floor life without special dry-pack or desiccant requirements during manufacturing and assembly. However, MSL rating applies to solder joint reliability, not mating contact corrosion in storage. The gold-plated mating contacts (10.0µin thickness) and phosphor bronze base material provide moderate corrosion resistance in typical indoor storage. In outdoor, marine, or salt-spray environments (ASTM B117), the unmated gold contacts are vulnerable to white corrosion (copper oxide/phosphorus oxide compounds) and red rust (iron contamination) over weeks to months. The LCP insulation material does not absorb moisture significantly, so the connector body remains dimensionally stable. For long-term storage in harsh environments, store the MMS-116-02-LM-SV in sealed desiccant containers or apply a conformal coating (if unmated contacts will remain exposed). If the connector will be mated and remain in service under such conditions, the mating interface provides mechanical protection, and the gold finish will protect adequately for the service life. Consider environmental sealing or encapsulation around the unmated connector if it will remain in a corrosive atmosphere.
• What is the maximum current I can safely route through a single MMS-116-02-LM-SV contact in a continuous-operation scenario? The MMS-116-02-LM-SV is rated at 3.9A per contact maximum. This rating assumes typical ambient temperature (around 20-25°C) and standard PCB thermal design. In continuous-operation scenarios, account for I²R heating in both the contact resistance and the solder joint. At 3.9A, contact resistance (typically 10-20 milliohms for gold-plated phosphor bronze) generates roughly 150-150mW per contact, which elevates local temperature by several degrees Celsius depending on PCB thermal mass and airflow. If your application will run continuously near 3.9A per contact, perform thermal simulation or empirical testing to verify that contact and solder joint temperatures remain within the -55°C to 125°C operating window. For conservative designs, operate at 50-70% of rated current (2.0-2.7A per contact) to extend contact life and maintain contact resistance stability. Also verify that your mating plug connector is rated for the same current; mismatched ratings could create a thermal bottleneck in the connector interface. Intermittent applications can tolerate higher instantaneous currents (peak rating may exceed 3.9A) if duty cycle allows thermal recovery.
• How does the MMS-116-02-LM-SV perform when substituting for a through-hole connector in a rework or upgrade scenario? The MMS-116-02-LM-SV is surface-mount only, so direct mechanical replacement of a through-hole connector is not possible without PCB modification. If you are redesigning a board to migrate from through-hole to SMD, the MMS-116-02-LM-SV offers several advantages: reduced PCB height (surface-mount vs. stacked through-hole), faster automated assembly, and no drilling; however, it also introduces rework complexity. SMD rework requires a reflow station or hot-air rework tool, whereas through-hole connectors can be desoldered with a solder wick or vacuum. If rework frequency is expected to be high in production, account for the reflow thermal cycle count and potential PCB laminate degradation. The solder termination footprint for the MMS-116-02-LM-SV is smaller than typical through-hole pads, which can reduce available copper area for thermal management. In rework scenarios, protect nearby components from reflow heat and use solder paste with appropriate viscosity for the tight SMD pitch. If you need frequent field rework without reflow equipment, a through-hole or press-fit connector may be more practical despite the higher PCB profile.
• What thermal management considerations apply to the MMS-116-02-LM-SV in a sealed or potted enclosure? When the MMS-116-02-LM-SV is installed in a sealed or potted enclosure, heat dissipation from the connector contacts becomes more challenging. The LCP insulation material has relatively low thermal conductivity (approximately 0.25-0.30 W/m·K), so heat generated in the contacts does not easily transfer to the surrounding potting compound. If the connector is potted directly (contacts submerged in epoxy, silicone, or polyurethane), the potting compound acts as a thermal insulator, trapping heat at the contact junction. Operating at 3.9A per contact in a potted assembly will cause localized temperature rise of 10-20°C or more above the ambient (potted) temperature. To mitigate this, either reduce contact current below 3.9A, increase airflow if the enclosure has ventilation, or specify a thermally conductive potting compound (filled with ceramic or alumina particles, ~1-2 W/m·K). If the connector remains accessible (not potted), ensure adequate PCB cooling through vias or thermal planes beneath the solder joints. The operating temperature range of -55°C to 125°C applies to the connector itself; verify that your potting material and any potted components also support this range, as mismatched thermal expansion coefficients can create mechanical stress.
• Can the MMS-116-02-LM-SV be used in applications requiring rapid connect-disconnect cycles, and what maintenance or replacement intervals should be planned? The MMS-116-02-LM-SV is designed for board-to-board or cable interconnect with a push-pull fastening mechanism, which enables field mating and unmating. The connector can tolerate hundreds to thousands of insertion cycles depending on environmental conditions and contact force. In laboratory environments with gentle, controlled mating, cycles often exceed 5,000 without significant degradation. However, in harsh field conditions (abrasive materials, forced insertion, corrosive atmosphere), contact wear and plating erosion accelerate, and gold plating (10.0µin) may show visible wear after 1,000-2,000 cycles. At each disconnect, the mating contacts experience wiping action that removes oxidation and refreshes the contact interface, prolonging electrical reliability. Plan preventive maintenance at intervals aligned with your expected duty cycle: for frequent-use applications (>100 cycles per month), inspect contacts every 12-24 months for corrosion or mechanical damage; for infrequent use, an annual inspection is typically sufficient. When contact resistance rises above your application threshold or mating becomes difficult, replace the entire connector rather than attempting to repair individual contacts. Samtec supplies replacement MMS-116-02-LM-SV connectors as spare parts, making field replacement straightforward if the solder joints are accessible.
• What are the electrical isolation and voltage creepage considerations for the MMS-116-02-LM-SV in mixed-voltage systems? The MMS-116-02-LM-SV datasheet does not specify a voltage rating, indicating it is suitable for low-voltage applications typical of digital logic and low-power analog circuits (typically under 30V for standard PCB creepage rules). The LCP insulation material provides adequate dielectric strength for standard PCB operating voltages, but creepage distance between adjacent contacts is limited by the 0.079" (2.00mm) pitch. At 2.00mm pitch, creepage distance along the insulation surface is approximately 2.0-2.5mm (contact center-to-center), which follows IEC 60664-1 for Category II equipment at pollution degree 2 up to approximately 50V working voltage assuming normal spacing rules. If your design includes circuits at 48V or higher, or if you are mixing high-voltage and low-voltage signals through the same MMS-116-02-LM-SV connector, perform a creepage and clearance calculation per your applicable safety standard (IEC 60950, IEC 61010, etc.). Consider routing high-voltage and low-voltage signals through separate connector positions, or use the push-pull release mechanism to ensure the connector is fully mated before high voltage is applied. For isolation-critical applications (medical, industrial control), use optical isolation or separate connectors rather than relying on PCB creepage alone.