MTLW-136-07-G-S-236

FAQFrequently Asked Questions

• What are the key design considerations when selecting the MTLW-136-07-G-S-236 for a high-reliability embedded system that operates across industrial temperature ranges? The MTLW-136-07-G-S-236 is rated for -55°C to 125°C operation, making it suitable for industrial applications. The phosphor bronze contacts with 10µm gold plating on the mating surface provide corrosion resistance in temperature cycling scenarios. However, designers should account for thermal expansion differences between the LCP insulation body and the PCB material during wide temperature swings. The push-pull fastening mechanism maintains contact pressure across temperature excursions, but PCB layout should minimize mechanical stress on the connector footprint by avoiding rigid mounting constraints nearby.
• Can the MTLW-136-07-G-S-236 be used as a direct replacement for older 0.100-inch pitch headers, and what compatibility factors should I verify? The MTLW-136-07-G-S-236 shares the standard 0.100-inch (2.54mm) pitch common to many legacy connector families, but compatibility requires verification of several factors: mating contact length (6.00mm for this model), post length (3.40mm), overall contact length (10.92mm), and the unshrouded design. If your existing application uses shrouded headers or different contact geometries, mechanical fit may fail even with matching pitch. The 36-position, single-row configuration must also match your PCB layout. Cross-reference the original part number's datasheet to confirm all physical dimensions align before substitution.
• What current distribution strategy should I use when the MTLW-136-07-G-S-236 carries signals exceeding 5.2A per individual contact? The MTLW-136-07-G-S-236 supports a maximum of 5.2A per contact. For applications requiring higher current density, designers must either parallel multiple contacts or employ external current distribution architecture. When paralleling contacts, ensure trace routing on the PCB balances current flow to prevent hot spots on single contacts. If paralleling, increase the effective contact count proportionally—for example, using two parallel contacts per signal line doubles the current capacity to approximately 10.4A (accounting for contact resistance variance). Alternatively, consider upgrading to higher-amperage connector families if the application systematically requires current handling beyond single-contact ratings.
• How does the thin gold plating on the MTLW-136-07-G-S-236 post (3.00µin) affect long-term reliability in high-cycle mating scenarios? The MTLW-136-07-G-S-236 specifies 3.00µin (0.076µm) gold thickness on the post, which is below the 50µin typical for high-reliability connectors. This thinner post plating is cost-optimized for limited mating cycles or static applications but may show accelerated wear under repeated insertion/extraction. In test socket or automated test equipment (ATE) scenarios involving hundreds or thousands of cycles, post plating erosion can eventually expose base metal, increasing contact resistance and intermittent connection risk. For applications exceeding 100 mating cycles, evaluate connectors with thicker post plating (≥50µin) or ensure connector maintenance protocols and periodic replacement schedules are factored into system design.
• What soldering profile and thermal considerations apply when reworking boards populated with the MTLW-136-07-G-S-236? The MTLW-136-07-G-S-236 uses an LCP insulation body rated for UL94 V-0, which limits continuous operating temperature but does not dictate reflow soldering temperature. Standard lead-free reflow profiles (peak 260°C) are acceptable for initial assembly. During rework or repair, localized heating above 260°C should be minimized and brief to prevent LCP softening or distortion. The phosphor bronze contacts and gold plating tolerate standard thermal cycling, but repeated thermal excursions degrade solder joint fatigue life. If the board will undergo multiple rework cycles, design for accessibility and use lower-temperature rework techniques (e.g., selective soldering, focused heat) to preserve the solder joint and insulation integrity.
• Is the MTLW-136-07-G-S-236 suitable for applications requiring moisture resistance, and what precautions should be taken? The MTLW-136-07-G-S-236 carries Moisture Sensitivity Level (MSL) 1, indicating unlimited moisture tolerance and no pre-dry bake requirement before soldering. The LCP insulation material inherently resists moisture absorption, and the phosphor bronze contacts with gold plating are resistant to corrosion in humid environments. However, the unshrouded design exposes contacts directly to ambient conditions; in marine, outdoor, or high-humidity industrial settings, consider conformal coating or housing the connector within an enclosure to prevent salt spray or condensation ingress. Long-term exposure without protection may lead to contact oxidation at the connector-mating interface, especially if the mating cycle is infrequent and the connection sits dormant in a humid environment.
• What electrical performance degradation should I expect if the MTLW-136-07-G-S-236 is used in high-speed digital signaling above 100 MHz? The MTLW-136-07-G-S-236 datasheet does not specify impedance matching, propagation delay, or high-frequency electrical characteristics. The connector is optimized for general-purpose board-to-board connections and standard digital logic signaling rather than controlled-impedance applications. For signals exceeding 100 MHz, contact resistance and insulation discontinuities introduce signal integrity challenges: reflections may occur if the connector impedance mismatch exceeds acceptable limits for your signal integrity budget. At these frequencies, insertion loss and crosstalk between adjacent pins become measurable. High-speed applications should employ connectors specifically designed for impedance control or consider differential signaling with shorter traces and proper termination to compensate for the MTLW-136-07-G-S-236's generic electrical profile.
• Can the MTLW-136-07-G-S-236 be mated with non-Samtec receptacle connectors, and what risks arise from cross-manufacturer compatibility? The MTLW-136-07-G-S-236 is a header with square male pins at 0.100-inch pitch. Many connector manufacturers (3M, TE Connectivity, Amphenol, etc.) produce compatible receptacles for this standard pitch, but mechanical fit, contact geometry, and plating chemistry differences introduce risks. Cross-manufacturer mating may result in loose or tight fits, causing high contact resistance, intermittent connections, or mechanical damage to the thinner gold post plating. If forced together, receptacle contacts may flex excessively or scrape the MTLW-136-07-G-S-236 post, accelerating wear. Best practice is to use Samtec-matched receptacles (e.g., MTLW series) or verify physical and electrical compatibility through bench testing before deploying in production. Document the validated pairing in design specifications.
• How should the MTLW-136-07-G-S-236 be footprinted on the PCB to accommodate manufacturing tolerances and ensure reliable solder joint formation? The MTLW-136-07-G-S-236 post length is 3.40mm, and typical PCB thickness is 1.6mm, leaving approximately 1.8mm of post extending above the board for wave or reflow soldering. PCB footprint design must account for post diameter (nominally 0.64mm square), manufacturing tolerances (±0.10mm), and solder fillet development. Pad diameters should be sized to allow adequate solder volume (typically 1.0–1.2mm diameter pads) without bridging to adjacent pads at 0.100-inch pitch. Solder mask clearances should expose pads while preventing slump into vias. The unshrouded design offers no mechanical standoff; the solder fillet alone holds the connector. Avoid deep vias or plated-through holes directly under the pad center, as they can create weak joints or solder wicking channels. Use IPC-A-610 Class 2 or higher acceptance criteria for production inspection.
• What migration path exists if I need to upgrade from the MTLW-136-07-G-S-236 to a higher-pin-count or shrouded variant for a redesign? The MTLW-136-07-G-S-236 is the base product MTLW-136 with specific termination and contact finish options. Samtec's MTLW series includes variants with different pin counts (e.g., MTLW-118 for 18 positions, MTLW-154 for 54 positions) and shrouded versions for improved keying and EMI shielding. Migration requires PCB layout redesign because row spacing and pitch remain constant, but overall connector footprint expands with pin count. If upgrading to a shrouded variant (e.g., MTLW-136S), verify that shroud geometry does not interfere with adjacent components. The contact length, post length, and plating specifications may differ across variants; cross-reference the specific part number to confirm electrical and thermal performance remains acceptable. Plan for test validation of prototype boards before full production transition.
• What are the reliability implications of using the MTLW-136-07-G-S-236 in a push-pull mated application where the connector experiences frequent disconnection cycles? The MTLW-136-07-G-S-236 features a push-pull fastening mechanism, enabling repeated mating and unmating without additional tools. However, the mechanical force required to overcome the push-pull friction may, over many cycles, induce micro-motion at the solder joint interface, accelerating fatigue crack initiation. The thin post plating (3.00µin) also degrades with each insertion cycle as receptacle contacts abrade the post surface. Field data suggests reliable operation for 50–200 mating cycles under normal conditions; beyond that, contact resistance and intermittency risk rise significantly. For applications requiring frequent disconnection (test fixtures, modular systems), establish preventive maintenance schedules, inspect for visible contact wear, and plan periodic connector replacement. Specify connectors with thicker post plating if cycle counts are expected to exceed 200.
• Can the MTLW-136-07-G-S-236 be used in a vibration-prone environment without additional mechanical retention, or should I add supplementary fastening? The MTLW-136-07-G-S-236 relies on the push-pull mechanism and solder joint for mechanical retention; it does not include screw holes or other fastening provisions. In high-vibration environments (automotive, aerospace, heavy machinery), vibration can induce cyclic shear stress on the solder joint, leading to thermal fatigue and eventual joint cracking. The unshrouded design offers no mechanical support to the mated connector. For applications with sustained vibration (e.g., ≥2g acceleration), add supplementary retention: potting or conformal coating around the solder joint to dampen flexure, mechanical standoffs or brackets to reduce lever arm stress, or consider a higher-grade connector with integral keying and mechanical locks (e.g., latched rectangular connectors). PCB vibration analysis during design may identify resonant modes at the connector location; if resonance near operating frequencies is detected, add localized stiffening or damping.
• What EMI shielding or filtering strategy should be employed if the MTLW-136-07-G-S-236 carries sensitive analog or power signals in a noisy electromagnetic environment? The MTLW-136-07-G-S-236 is an unshrouded header with no integrated shielding; it offers no EMI suppression by itself. If the connector carries sensitive analog signals (e.g., sensor inputs, audio) or power rails in a noisy environment (industrial VFD drives, RF transmitters, switching power supplies), radiated EMI will couple into the connector traces and signal lines. Mitigation strategies include: routing signal pairs adjacent to ground or shield pins within the connector footprint to maximize capacitive coupling; adding ferrite beads or LC filters at the connector entry point; implementing star grounding or multi-point grounding at the connector backplane; or using shielded cables external to the connector if the connector interfaces with off-board signals. Consider upgrading to a shielded connector variant (if available from Samtec) if the noise environment is severe or the application requires FCC/CE compliance at high SNR.
• How does the MTLW-136-07-G-S-236 perform in cryogenic or thermal cycling stress tests, and are there material compatibility concerns? The MTLW-136-07-G-S-236 is rated -55°C to 125°C, covering typical industrial ranges. The LCP insulation material has a glass transition temperature (~155°C at typical values) well above the rated maximum, but below reflow soldering peaks. Phosphor bronze contacts maintain ductility at low temperatures, and gold plating resists embrittlement. However, repeated thermal cycling between extremes induces differential expansion between the copper post, LCP insulation, and PCB material (typically FR-4 or similar), creating cyclic stress at the solder joint interface and connector body. In cryogenic scenarios (below -55°C), LCP embrittlement risk increases; verify material specifications for the specific LCP grade used in your connector lot. Thermal shock (rapid transitions, e.g., -55°C to 125°C in seconds) is more stressful than gradual cycling. If your application exceeds the rated temperature range or requires extreme thermal cycling, conduct thermal cycle testing (e.g., IPC-9701 or mil-spec profiles) on prototypes to validate solder joint reliability.
• What design margin and derating factors should I apply to the MTLW-136-07-G-S-236 current rating of 5.2A per contact in a continuous operating scenario? The MTLW-136-07-G-S-236 specifies 5.2A per contact, but this rating typically assumes 20°C ambient or specific test conditions. In continuous operation at elevated ambient temperatures (e.g., 100°C in an enclosure), contact resistance generates heat: P = I²R. The contact resistance of gold-plated phosphor bronze headers is typically 10–50 mΩ, so 5A dissipates 0.25–1.25W per contact. At elevated temperature, thermal dissipation is hampered, and the contact temperature may approach or exceed rated limits. Thermal modeling is required to confirm margin. Industry best practice applies a 50–70% derating factor for continuous current: design for 2.6–3.6A per contact under continuous load. For brief transient currents, the full 5.2A may be acceptable if heat dissipation time is sufficient. Perform thermal FEA or bench testing if sustained currents near the rating are planned; add thermal interface materials or heat sinking if necessary to maintain contacts below rated temperature.
• Is the MTLW-136-07-G-S-236 suitable for hand-soldered prototypes, or should it only be wave or reflow soldered in production? The MTLW-136-07-G-S-236 can be hand-soldered by skilled technicians, but the large contact count (36 positions) and small pitch (0.100 inch) increase the risk of solder bridges, cold joints, and incomplete wetting. LCP insulation material has a glass transition temperature that allows hand-soldering with standard irons (~350°C tip), but prolonged contact with a hot iron can degrade the insulation. Best practice for prototypes: use a temperature-controlled soldering iron (≤350°C), minimize dwell time at each joint (3–5 seconds), and apply flux liberally to promote wetting. Inspect joints under magnification for voids or bridges. For production volumes, wave soldering or selective reflow is preferable for consistency and traceability. If hand-soldering prototypes, create a rework procedure document and train technicians; defects introduced in prototype builds often propagate to production if the process is not controlled.
• What considerations apply if the MTLW-136-07-G-S-236 is used in a design that requires future field serviceability or connector replacement without PCB damage? The MTLW-136-07-G-S-236 is through-hole soldered directly to the PCB, making field removal challenging without risking PCB laminate damage or pad lifting. The 36 pins generate significant solder thermal mass; heating all joints simultaneously to desoldering temperature (≥230°C lead-free) requires focused heat application to avoid distributed board heating. If field serviceability is a requirement, consider: using a connector footprint with associated desoldering pads or large pads to distribute thermal stress; potting the solder joints to prevent flux migration but worsening thermal removal; or specifying a socket or receptacle-based design where the header can be replaced by replacing a removable module. Alternatively, design for board-level modularity where the entire connector and surrounding circuitry are on a replaceable PCB assembly. Document the field replacement procedure and provide connector removal tools (desoldering braid, solder wick, or hot-air station specifications) in service documentation.
• How does the MTLW-136-07-G-S-236 compare to ribbon cable connectors or other board-to-cable alternatives for data acquisition or signal distribution applications? The MTLW-136-07-G-S-236 is a board-to-board header optimized for low-profile mated height and direct PCB interfacing. Ribbon cable connectors (e.g., IDC or FFC types) offer flex or flat cable routing for applications requiring off-board connectivity or mechanical routing around obstacles. Trade-offs: the MTLW-136-07-G-S-236 provides better contact reliability and lower cost for static board-to-board connections but cannot route signals away from the connector area without additional cabling. Ribbon connectors offer routing flexibility but introduce additional transition loss, crosstalk risk, and potential ingress points for moisture if not properly jacketed. For data acquisition, the MTLW-136-07-G-S-236 is preferred if all signal destinations are on the same PCB or a tethered secondary PCB. If signals must route to remote sensors or modules, an off-board connector on a flex cable (e.g., FFC or round cable with D-sub) is more practical. Select based on routing constraints and mechanical fit requirements.
• What role does the phosphor bronze contact material in the MTLW-136-07-G-S-236 play in long-term electrical stability, and how does it compare to alternatives? Phosphor bronze is a copper alloy offering good electrical conductivity (approximately 5–10 mS/m relative to pure copper), work-hardening properties for maintaining contact spring force, and corrosion resistance superior to brass. The MTLW-136-07-G-S-236 uses phosphor bronze with gold plating (10µm mating side), which combines the structural benefits of the bronze with corrosion protection from gold. Over decades of storage or operation, the thin gold plating may locally abrade or wear through, exposing the bronze base; however, oxidation of phosphor bronze occurs slowly compared to bare copper or lower-grade alloys, maintaining reasonable contact resistance even if plating is compromised. Competitive alternatives (beryllium copper, nickel-plated brass) offer different trade-offs: beryllium copper provides superior spring force but poses manufacturing and disposal hazards; nickel plating is thicker but can develop corrosion issues under humidity. Phosphor bronze is an industry-standard choice for general-purpose connectors like the MTLW-136-07-G-S-236, balancing cost, conductivity, durability, and environmental safety.
• Should the MTLW-136-07-G-S-236 be included in a formal connector qualification process for a medical device or aerospace application, and what testing is recommended? The MTLW-136-07-G-S-236 carries RoHS3 compliance and UL94 V-0 flammability rating, supporting some regulated industries; however, it is not specifically qualified to medical (e.g., IEC 60601) or aerospace (e.g., MIL-DTL-38999) standards by design. For medical devices (class II or III), regulatory pathways typically require connector qualification via established standards (IEC 61076 for industrial connectors, or custom biocompatibility testing if the connector contacts body fluids). For aerospace applications (civil or military), connectors must meet MIL-DTL or military performance specifications. If the MTLW-136-07-G-S-236 is proposed for these applications, initiate a design control review to assess whether the connector's specifications (contact plating, insulation material, current rating, operating temperature) meet your application standards. Conduct or source third-party qualification testing: contact resistance cycling, thermal cycling, salt-fog corrosion, vibration endurance, and manufacturing process audits. Document all test results and design decisions in a connector qualification report. Failure to do so risks product recalls or certification delays.