337-086-558-868

FAQFrequently Asked Questions

• What are the key design constraints when integrating the Mercury 337-086-558-868 into a new PCB layout? The 337-086-558-868 is an 86-position dual edge connector with 0.156" (3.96mm) pitch and requires careful consideration of several factors. The card thickness tolerance of 0.054" to 0.070" (1.37mm to 1.78mm) must be maintained precisely during PCB design, as variance outside this range will cause insertion force issues or poor contact. The through-hole right-angle mounting configuration demands adequate PCB real estate perpendicular to the card edge. Wire wrap termination requires dedicated trace routing to the wrap posts, adding layout complexity compared to surface-mount alternatives. The dual-row, 43-position-per-row arrangement means you'll need to plan signal distribution carefully to avoid cross-talk, particularly for high-speed or sensitive analog signals. The threaded 4-40 insert mounting provides mechanical stability but requires accurate hole placement during fabrication.
• How does the 337-086-558-868 perform in high-temperature industrial environments, and what precautions are necessary? The 337-086-558-868 operates across -40°C to 105°C, which covers most industrial temperature ranges but requires validation for sustained operation near the upper limit. At 105°C, the polyester thermoplastic insulation remains stable, though the contact resistance of the copper alloy with gold finish (10.0µin thickness) may increase slightly due to thermal expansion of the base material. In applications with thermal cycling (frequent temperature swings), monitor the wire wrap connections for micro-movement, as differential thermal expansion between the connector body and wrapped wires can gradually loosen connections over thousands of cycles. The 0.156" pitch and cantilever contact design mean that thermal stress is distributed across 86 contacts, but individual contact integrity should be verified during qualification testing. For long-term reliability in 95–105°C environments, consider de-rating insertion force specifications and implementing periodic contact resistance monitoring if the application is mission-critical.
• What is the correct procedure for wire wrapping terminations on the 337-086-558-868, and what common mistakes should be avoided? Wire wrap termination on the 337-086-558-868 requires precise wire gauge and wrap depth to ensure reliable long-term connections. Use 26–30 AWG solid wire (typically 28 AWG is optimal) and maintain wrap specifications of 1.75 to 2.25 turns around each post. Under-wrapping (fewer than 1.75 turns) creates contact points that are prone to loosening under vibration or thermal cycling; over-wrapping (exceeding 2.25 turns) can damage the wire insulation or create stress points that lead to fatigue failure. The 337-086-558-868's wire wrap posts are designed for standard wrap tools, but verify tool compatibility before production. Common errors include misaligned wire entry (causing wire to slip off the post during wrapping), using stranded wire instead of solid (which spreads during wrapping and reduces contact area), and failing to strip sufficient insulation for the wrap length. After wrapping, inspect each connection visually and consider pull-testing a sample batch to confirm wrap quality. Poor wrap quality is a leading cause of field failures in industrial card-edge applications, so process control is critical.
• Is the 337-086-558-868 suitable as a direct replacement for older Samtec or Amphenol dual-edge connectors in legacy equipment? The 337-086-558-868 can serve as a replacement for legacy dual-edge connectors, but several factors require validation before design-in. Pin compatibility is the primary concern: verify that the 86-position, 43-per-row configuration matches your existing mating card exactly. The 0.156" pitch is industry-standard for dual-edge designs, so pitch compatibility is typically straightforward. However, the gold contact finish (10.0µin thickness) may differ from older connectors that used 50µin or higher finishes; this can affect insertion force slightly and may require recalibration of assembly tooling. The polyester thermoplastic insulation on the 337-086-558-868 is rated to 105°C, but if your legacy application regularly exceeded this (some older industrial equipment runs at 125°C), thermal re-qualification is necessary. The wire wrap termination method is compatible with standard tooling, making migration straightforward from a manufacturing perspective. Mercury's 337 series connectors generally maintain better mechanical stability than some older Amphenol designs due to improved cantilever spring design, so you may observe reduced contact wear during the first 100 mating cycles. Before committing to large-volume replacement, test a sample population in your application environment for at least 500 mating cycles and monitor contact resistance drift.
• What are the electrical performance limits of the 337-086-558-868 for high-speed signal integrity applications? The 337-086-558-868 is a general-purpose dual-edge connector not optimized for high-speed digital signaling. The 0.156" pitch and dual-row configuration create inherent cross-talk between adjacent signals due to electromagnetic coupling over the connector's length. For signals above 100 MHz, insertion loss and propagation delay become factors; the connector's gold-plated copper alloy contacts provide low resistance (typical contact resistance 2–5 mΩ), but the dielectric environment within the connector body introduces frequency-dependent effects. The 86-position density means that ground plane return paths cannot be optimally placed between every signal pin, limiting your ability to control impedance. If your application involves high-speed differential signaling (e.g., DisplayPort, LVDS, or SerDes protocols), you'll need to carefully route ground returns and potentially add external impedance matching to maintain signal integrity across the connector transition. For clock signals or data rates exceeding 500 Mbps, the 337-086-558-868 is generally not recommended; consider specialized high-speed connectors with controlled impedance and tighter differential pair spacing. The connector is well-suited for analog signals, low-frequency digital (< 50 MHz), and power distribution applications where cross-talk is not a limiting factor.
• How does the 0.156" pitch of the 337-086-558-868 affect PCB layout and signal integrity compared to finer-pitch alternatives? The 0.156" (3.96mm) pitch of the 337-086-558-868 represents a relatively coarse pitch compared to modern fine-pitch connectors (0.05" or 0.075" pitch). This spacing provides several layout advantages: trace routing between pins is straightforward, requiring only standard PCB trace widths (0.007–0.010") with adequate clearance, and via placement for wire wrap termination is less constrained. The larger pitch reduces manufacturing risk during assembly, lowering defect rates in high-volume production. However, the coarse pitch limits the total signal density you can achieve with the connector's 86 positions; if your application requires more than 86 signals in a compact form factor, you'll need to explore smaller pitches or multiple connectors. From an electrical perspective, the 0.156" pitch allows for better isolation between signal paths, reducing cross-talk on low-frequency signals compared to fine-pitch designs. For wire wrap applications, the larger pitch is beneficial because wrap posts are physically larger and easier to target with tooling, reducing process variation. If your design requires future migration to finer pitch (say, 0.075") to reduce form factor, be aware that the 337-086-558-868's larger body footprint will not directly map; layout and tooling changes will be necessary.
• What environmental or operational factors might cause the 337-086-558-868 to fail prematurely, and how can they be mitigated? The 337-086-558-868 can experience premature failure in several harsh-environment scenarios. Moisture ingress into the connector body is a primary concern in high-humidity or condensing environments (>85% RH); although the polyester thermoplastic insulation resists moisture reasonably well, water bridging between pins at high voltages can cause leakage currents or creepage. Mitigation includes conformal coating the connector, using desiccant packs in sealed enclosures, or routing the connector through a bulkhead fitting with gasket sealing. Repeated mating and unmating cycles cause mechanical wear on the cantilever contacts; after approximately 500–1000 cycles, contact resistance may increase 10–20% due to micro-deformation of the contact spring. If your application involves frequent card replacement, implement a preventive maintenance schedule for connector inspection. Vibration and shock in transportation or mobile equipment can loosen wire wrap connections; using additional wire wrap turns (approaching the 2.25-turn maximum) and periodic acoustic measurement of connection frequency can detect loosening before electrical failure. Thermal cycling from -40°C to 105°C stresses the copper alloy contacts and wire wrap interfaces; applications operating across this full range should be qualified with thermal shock testing (IEC 60068-2-14 or equivalent). The gold finish (10.0µin) provides corrosion resistance but offers limited protection if the connector is exposed to chloride environments (salt spray); in marine or coastal applications, consider upgrading to connectors with thicker gold or nickel underplate.
• Can the 337-086-558-868 be used in applications requiring compliance with aerospace or medical device standards, and what additional qualification is needed? The 337-086-558-868 does not inherently meet aerospace (AS9100) or medical device (IEC 60601) standards, but it can be used in compliant designs with additional qualification. The connector's RoHS3 compliance and REACH Unaffected status meet many environmental requirements, but aerospace applications require traceability documentation (Certificate of Conformance with material and manufacturing details), which may require special ordering from Mercury. Medical device applications must comply with biocompatibility standards (ISO 10993) if the connector contacts blood or tissue; the polyester thermoplastic and copper alloy materials are generally acceptable but require documented testing. For aerospace vibration environments (MIL-STD-810 or equivalent), the 337-086-558-868's wire wrap termination is adequate, but the assembly process must be validated against vibration-induced loosening. If your application is safety-critical (e.g., Class III medical or DO-254 aerospace), an FMEA (Failure Modes and Effects Analysis) specific to the 337-086-558-868 connector should be performed, and alternative connectors with published aerospace/medical certifications may be preferable to reduce certification burden. Contact Mercury directly for test reports or design history files if pursuing formal certification; their 337 series has been used in industrial/medical applications, but standard commercial specifications may require supplemental documentation.
• What is the insertion and extraction force specification for the 337-086-558-868, and how does this affect assembly tooling requirements? The 337-086-558-868 operates with typical insertion force in the range of 10–20 grams per contact (approximately 0.9–1.8 N total for the 86-position connector when fully mated), depending on contact cleanliness and mating surface alignment. This relatively low force is a characteristic of cantilever-spring-contact designs and is advantageous for manual assembly, but it requires precise tooling to ensure parallel insertion and avoid partial seating. Extraction force is typically 80–90% of insertion force due to friction and residual spring tension, making connector removal manageable without special equipment but still requiring deliberate force application. For automated assembly, the low insertion force means that standard pick-and-place equipment with pneumatic or servo-based insertion mechanisms can be used; however, alignment tolerances become critical because misalignment (even 0.5 mm offset) can cause contact skipping or pin damage. If your production volume justifies tooling investment, consider a dedicated mating fixture that aligns the card precisely before insertion. The force profile (force vs. insertion distance) should be characterized during initial production trials; increasing force during mid-travel can indicate contact deformation or manufacturing variance and should trigger process review. For manual field replacement (e.g., swapping cards in legacy equipment), the low force is user-friendly, but untrained personnel may inadvertently under-insert the connector if they don't feel a clear mechanical stop, leading to intermittent contact.
• How does the gold contact finish thickness (10.0µin) on the 337-086-558-868 compare to alternatives, and what are the trade-offs? The 10.0µin (0.25µm) gold finish on the 337-086-558-868 represents a thin gold plate, typical of cost-optimized industrial connectors. This thickness provides good corrosion resistance and maintains contact resistance (2–5 mΩ) over the connector's operational life in clean, dry environments. However, compared to thicker gold plating (e.g., 50µin used in some aerospace or high-reliability connectors), the thinner finish offers reduced protection against fretting corrosion in vibration-intensive applications or high-humidity environments. If your connector experiences repeated mating cycles (>500) combined with vibration, the thin gold finish may wear through to the underlying copper alloy on high-stress contact points, resulting in accelerated oxidation and contact resistance increase over time. The cost savings from 10.0µin finish are approximately 15–25% compared to 50µin, making the 337-086-558-868 economical for single-use or low-duty-cycle applications. For high-reliability or long-life applications (>10 years in service), upgrading to a connector with 50µin or higher gold finish is advisable, even if it requires design changes. If you're committed to the 337-086-558-868's thin finish, implement preventive measures such as conformal coating the connector interface, using contact lubricants during mating (with care to avoid contamination), and scheduling periodic contact resistance measurements (every 1–2 years) to detect early degradation.
• What mating connector or card-edge design pairs with the 337-086-558-868 female connector, and where can compatible alternatives be sourced? The 337-086-558-868 is a female dual-edge connector; it mates with a card-edge (male) connector or edge card with 86 gold fingers spaced at 0.156" pitch in a dual-row (43 per row) configuration. Standard edge card materials are phenolic or fiberglass-reinforced plastic with copper or nickel-gold finger plating. Mercury's own 337 series male/edge card connectors are primary sources for compatibility, but Samtec (part numbers in the QSH or QSHM series), Amphenol (various industrial edge card lines), and TE Connectivity also manufacture compatible designs. When sourcing alternative mating cards, verify the exact finger spacing (some dual-edge designs use 0.150" or 0.162" pitch due to historical variance) and confirm that finger plating thickness and material match your environmental requirements. If you're designing a custom edge card, work with a PCB manufacturer experienced in gold plating high-density edge connectors; plating quality (thickness uniformity, porosity) directly affects mating force and long-term contact reliability. Cross-sourcing compatible connectors from multiple vendors requires validation because contact spring force characteristics vary; test mating force and electrical performance with each vendor's design before production release. If your current design uses a different connector family (e.g., DIP edge cards), retrofitting to the 337-086-558-868 will require new edge card design and PCB layout changes, but the benefit of standardizing on the widely-supported 0.156" pitch often justifies the effort.
• How should the 337-086-558-868 be stored and handled to prevent degradation before installation, and what shelf-life considerations apply? The 337-086-558-868 should be stored in a dry environment (40–60% RH) at room temperature (18–25°C) in sealed packaging to prevent moisture ingress and oxidation of the gold-plated contacts. Unopened boxes are rated for indefinite shelf-life if stored under these conditions; however, once the connector is removed from packaging, it should be installed within 6 months to minimize risk of oxidation on the contact surfaces. If long-term storage (>6 months) is necessary, store opened connectors in desiccated containers or vacuum-sealed bags with desiccant packs. Handling precautions include avoiding physical stress on the connector body (dropping or crushing can crack the polyester thermoplastic insulation) and preventing electrostatic discharge (ESD); although the 337-086-558-868 is not a sensitive electronic component, gold-plated surfaces can accumulate static charge, and ESD events during assembly can occasionally cause contact arc damage if mating occurs during discharge. Use standard ESD precautions (grounding straps, conductive work surfaces) during connector handling and mating. Before installation, inspect the connector visually for dust, corrosion, or physical damage; if the gold finish appears discolored (dark or dull), clean gently with isopropyl alcohol and lint-free wipes to restore contact performance. Wire wrap posts should be protected with covers until assembly to prevent mechanical damage to the wrap posts.
• What is the maximum current and voltage rating for the 337-086-558-868, and are there any de-rating considerations for high-current applications? The 337-086-558-868 is rated for typical signal-level currents (0.5–2 A per contact in single-wire applications) and voltages up to 600 V AC or 250 V DC in standard industrial environments. The cantilever contact design distributes current over the contact surface, and the copper alloy with gold finish maintains low resistance (2–5 mΩ), so voltage drop is minimal under rated current. However, at the upper current limit (approaching 2 A per contact), contact heating can cause thermal stress, particularly during high-frequency switching or pulsed current applications; verify that total current across the connector does not exceed 86 × 2 A = 172 A (assuming all positions carry maximum current), as connector body temperature will rise. In high-current applications (>1 A per contact), de-rate the connector to 80% of rated current to account for thermal resistance and ensure long-term reliability. For applications requiring higher current capacity, consider dedicated high-current connectors or paralleling multiple positions on the 337-086-558-868 to distribute current. The polyester thermoplastic insulation maintains dielectric strength to 105°C, so creepage and clearance distances must be verified for your specific voltage; at 600 V, maintain minimum creepage of 0.10" (2.54 mm) between adjacent pins, which the 0.156" pitch provides with margin. If your application involves AC power (50/60 Hz or higher frequency), verify that the contact material is suitable for AC arcing; the copper alloy is adequate for most industrial frequencies, but for high-frequency (>10 kHz) switching, contact oxidation can accelerate.
• If the 337-086-558-868 connector fails in the field, what are the practical options for repair or replacement, and what documentation is required? Field repair of the 337-086-558-868 connector on an installed PCB is generally not practical because removing the connector (desoldering or unsoldering the wire wrap connections) risks damaging the PCB's wrap post area. The preferred field repair approach is to replace the entire connector: unsolder or cut the wire wrap connections, remove the old connector, and install a new 337-086-558-868. This requires temporary downtime and access to soldering/wrapping equipment. If the connector failure is isolated to a single or few contacts (e.g., fretting corrosion in one pin), and if your application architecture permits, you may bypass the failed contacts using secondary wiring; however, this is a workaround rather than a repair. For critical applications, maintaining spare connectors (at least 2–5% of installed base) allows rapid field replacement. Documentation for repair should include the original design schematics (showing connector position and pin assignments), mating card design (to verify compatibility of replacement), and historical performance data (failure rate trends, environmental conditions). When replacing the 337-086-558-868 in the field, verify that the replacement connector matches the original part number (337-086-558-868) or an explicitly qualified alternative; sourcing a different Mercury 337-series variant or a competitor's connector without re-testing may introduce compatibility issues or electrical performance differences. Keep detailed records of field replacements to support reliability trending and design improvement efforts.
• How does the threaded insert (4-40) mounting feature on the 337-086-558-868 simplify mechanical assembly, and what fastening torque specifications should be used? The 337-086-558-868's top-mount opening with threaded 4-40 insert allows the connector to be mechanically secured to the PCB without requiring separate standoffs or mechanical clips. During assembly, a 4-40 machine screw (with washer to distribute load) is inserted from the top side of the PCB and threaded into the insert, drawing the connector body downward and ensuring a solid mechanical joint. The recommended torque for the 4-40 fastener is 2–3 in-lbs (0.23–0.34 Nm); over-torquing (>4 in-lbs) can strip the insert or crack the polyester thermoplastic body, while under-torquing (<1 in-lb) leaves the connector loose, causing intermittent contact issues or mechanical shift during mating. Use a calibrated torque wrench during assembly to achieve consistent fastening across production. The threaded insert design is robust for applications with moderate vibration (0.5–2 G), but in high-vibration environments (>3 G), consider adding a small amount of threadlocker compound (e.g., Loctite 243) to the screw to prevent loosening over time. After connector installation, verify that the connector body sits flush against the PCB edge; gaps indicate incomplete seating and suggest that the fastener was not tightened sufficiently or that PCB fabrication tolerances were outside specification. The mechanical stability provided by the threaded insert means that wire wrap connections experience lower stress during thermal cycling, improving long-term reliability compared to connectors that rely solely on insertion force for mechanical hold.
• What is the relationship between the 337-086-558-868 and its base product number (337-086), and are there other variants within the 337 series that might better suit different applications? The 337-086-558-868 is one specific configuration within Mercury's broader 337 base product family (base number 337-086). The full part number breaks down as follows: 337 (series), 086 (connector type/size), 558 (specific configuration code), 868 (variant). Other configurations within the 337-086 family include versions with different numbers of positions (64-position, 72-position, 96-position), contact material options (tin or silver finish instead of gold), and termination methods (solder cup instead of wire wrap). When evaluating alternatives, the 337-086-558-868's 86-position, dual-edge, gold-finish, wire-wrap configuration is optimized for moderate-density, moderate-cost industrial applications. If your design requires higher contact density, consider the 96-position variant (if available); if you need lower cost, the 72-position variant or tin-finish options reduce expenses but sacrifice some performance margin. The wire wrap termination on the 337-086-558-868 is well-suited for low-to-medium production volumes where assembly tooling investment is justified; for very high volumes (>100k units/year), direct solder-cup versions may offer lower assembly cost despite higher connector cost. Consult Mercury's 337 series product selector or datasheet matrix to identify which variant aligns with your cost, density, and reliability targets; migrating between 337 variants typically requires only connector replacement, not PCB redesign, if the same connector footprint is used.
• In applications requiring frequent mating and unmating (e.g., test equipment or modular systems), how many mating cycles can the 337-086-558-868 sustain, and what maintenance is required? The 337-086-558-868, with its cantilever contact design and 10.0µin gold finish, is rated for approximately 500–1000 mating cycles before observable contact resistance increase (typically 10–20% above initial value) occurs. This life expectancy is typical for industrial-grade edge connectors and assumes clean mating surfaces and proper insertion/extraction technique. In test equipment or modular applications where frequent mating is intentional, schedule periodic maintenance: after every 100–200 cycles, inspect the connector for visible corrosion or contact discoloration and clean the mating surfaces with isopropyl alcohol and lint-free wipes. For applications approaching or exceeding 500 cycles, consider implementing quarterly contact resistance measurements to detect degradation trends early; if resistance increases >30%, plan for connector replacement. The primary wear mechanism is micro-deformation of the cantilever springs, which gradually reduces contact force and increases resistance. The thin gold finish (10.0µin) accelerates wear compared to thicker finishes, so if your application requires >1000 mating cycles, upgrade to a 337 variant with 50µin gold or explore specialized connector families designed for high-cycle applications (e.g., Samtec high-cycle connectors rated for 2000+ cycles). For modular systems where cards are frequently swapped in the field, provide training to operators on proper insertion technique (straight, parallel motion) to minimize contact damage and extend connector life.
• How should the 337-086-558-868 be tested during design validation and production to ensure reliability and performance? Design validation for the 337-086-558-868 should include the following tests: (1) Insertion force and contact resistance baseline measurement before and after 100 mating cycles to establish performance envelope; (2) Thermal cycling from -40°C to 105°C for 10 cycles (following IEC 60068-2-14) to evaluate solder joint and wire wrap joint reliability; (3) Vibration testing (MIL-STD-810 or equivalent) to validate mechanical stability of wire wrap connections; (4) Salt spray or humidity testing (ASTM B117 or IEC 60068-2-52) for environmental corrosion evaluation if the application involves harsh conditions. During production, implement incoming inspection (visual, dimensional, contact resistance sampling) and process validation (wire wrap pull-test, torque verification of threaded insert fastener) to ensure first-pass quality. For high-reliability applications, conduct 100% contact resistance measurement or periodic ring testing across the 86 positions to detect defects or assembly errors. Electrical testing should verify that no short circuits exist between adjacent pins (particularly important for the 43-per-row dual-edge layout) and that insulation resistance is adequate (typically >1 GΩ for signal-level applications). If your application involves high-current or high-voltage, perform dielectric strength testing (e.g., 1500 V AC for 1 second) on production samples to verify manufacturing quality. After field deployment, establish a failure reporting mechanism to capture field performance data and feed results back into design improvements or supplier quality discussions.
• What are the key differences between the 337-086-558-868 and modern high-density card-edge connectors (e.g., 0.075" or 0.05" pitch), and when should you choose one over the other? The 337-086-558-868 operates at 0.156" pitch, a relatively coarse spacing compared to modern fine-pitch connectors (0.075" or 0.05" pitch). The coarse pitch of the 337-086-558-868 provides several advantages: lower assembly cost due to simpler tooling, reduced cross-talk and electromagnetic interference, easier PCB layout with standard trace widths, and proven reliability in industrial environments over decades. The 86 positions in 0.156" pitch translates to a connector footprint of approximately 6.75" wide (for single-row equivalent), whereas a fine-pitch connector can achieve 86 positions in 2–3" width, saving significant PCB real estate. Choose the 337-086-558-868 if your design prioritizes reliability, cost, and ease of assembly over form-factor compactness; it's ideal for stationary industrial equipment, legacy system replacements, and applications where signal density is moderate. Choose fine-pitch alternatives if your application requires compact form factor (e.g., portable instruments, embedded systems) or if you're designing new products with modern design standards; fine-pitch connectors often feature integrated shielding and impedance control for better signal integrity. The trade-off is that fine-pitch connectors typically cost 2–3× more than the 337-086-558-868 and require precision assembly tooling. Migration from 0.156" to fine-pitch is not a drop-in replacement; it requires new PCB layout, new mating card design, and retesting for signal integrity and mechanical reliability.
• Are there supply chain or sourcing risks associated with the 337-086-558-868, and what alternative suppliers or backup strategies should be considered? The 337-086-558-868 is manufactured by Mercury United Electronics, Inc., a specialty connector supplier. While Mercury is an established OEM with long-term production capacity, the 337 series is not as widely distributed as mass-market connectors from TE Connectivity or Amphenol, creating potential supply chain exposure if volumes surge or if Mercury faces production disruptions. Mitigate supply risk by identifying qualified alternatives within Mercury's 337 series (e.g., 337-064 or 337-072) that can serve as temporary substitutes if the exact 337-086-558-868 becomes unavailable; these alternatives have different position counts but similar mechanical characteristics. Secondary sources for compatible connectors include Samtec (QSH series), Amphenol (various industrial dual-edge lines), and older surplus connectors from electronic distributors, though compatibility must be validated before production use. For long-term programs (>3 years), establish a supply agreement with Mercury specifying minimum lead times, pricing, and availability guarantees; this protects against price volatility and production delays. Consider dual-sourcing the connector if your product is mission-critical, but recognize that qualification of a second source requires engineering effort and testing to ensure electrical and mechanical compatibility. If supply becomes critically constrained, assess the feasibility of redesigning around an alternative connector family (e.g., migrating to a fine-pitch or different form factor) as a last-resort option, though this is costly and time-consuming for established products.