381LQ682M080K052

FAQFrequently Asked Questions

• Can the 381LQ682M080K052 be safely replaced with the 80MXG6800MEFCSN30X02 in an existing 80V power supply design without PCB rework? While both capacitors share the same 6800µF/80V rating, the 80MXG6800MEFCSN30X02 has different physical dimensions and lead spacing than the 381LQ682M080K052. The 381LQ uses 0.394" (10.00mm) lead spacing with a 30mm diameter can. Before substitution, verify that the replacement's footprint matches your PCB layout exactly, including the snap-in mounting mechanism. If dimensions differ, PCB rework will be required. Additionally, confirm ESR specifications—the 381LQ682M080K052 has 41mOhm ESR @ 120Hz, which may differ in alternative parts, affecting ripple current performance and heat dissipation in your circuit.
• What are the thermal and lifetime implications of operating the 381LQ682M080K052 continuously at 105°C in an industrial power conditioning application? The 381LQ682M080K052 is rated for 2000 hours @ 105°C, meaning its usable lifetime at this maximum temperature is approximately 2000 hours (roughly 11 weeks of continuous operation). This rating applies when the capacitor is operated at rated voltage and ripple current. In industrial applications requiring multi-year service life, you must either derate the operating temperature to extend lifetime (typically doubling lifetime for every 10°C reduction below 105°C), limit ripple current below the 3.9A @ 120Hz or 4.49A @ 20kHz specifications, or plan preventive maintenance intervals. If your application requires 5+ years of continuous operation at elevated temperatures, the 381LQ682M080K052 may not meet reliability targets without thermal management or redundancy strategies.
• Is the 381LQ682M080K052 suitable for high-frequency switching power supplies, or should a lower-ESR alternative be considered? The 381LQ682M080K052 has an ESR of 41mOhm @ 120Hz, which is relatively high for switching applications that operate at 20kHz or above. While the capacitor can handle 4.49A ripple current @ 20kHz, the higher ESR generates excess heat (P = I²R) and may not provide adequate transient voltage ripple suppression compared to specialized low-ESR capacitors designed for switching converters. For high-frequency buck/boost or resonant topologies, evaluate whether the ripple voltage (V = ESR × ΔI) meets your output voltage regulation requirements. If output voltage ripple specification is tight (e.g., <50mV on a 5V rail), or if thermal management space is limited, consider lower-ESR alternatives such as polymer or hybrid capacitors, though this may require design validation.
• What precautions must be taken when using the 381LQ682M080K052 in a design that operates across the full -40°C to 105°C temperature range? The 381LQ682M080K052 spans a 145°C operating range (-40°C to 105°C), which creates two distinct design challenges. At -40°C, capacitance may increase and ESR will rise significantly (typically 200-300% of room-temperature values), reducing ripple current capacity and increasing voltage ripple. Ensure your circuit tolerates higher ESR and lower effective capacitance during cold startup. At 105°C, the capacitor approaches end-of-life after 2000 hours, and ESR increases further as the electrolyte ages. Design margin calculations should assume worst-case conditions: use the cold-temperature ESR for transient analysis and the aged high-temperature ESR for steady-state ripple calculations. Additionally, verify that circuit protections (overvoltage clamps, current limiters) function correctly across the full temperature range, since capacitor behavior—particularly leakage current and dielectric absorption—changes with temperature.
• How does the ±20% capacitance tolerance of the 381LQ682M080K052 affect circuit filtering performance and what design margin should be applied? The ±20% tolerance means the 381LQ682M080K052 could measure between 5440µF and 8160µF in production units. For filtering and energy storage applications, this tolerance directly impacts voltage ripple, voltage sag during transient events, and hold-up time calculations. When designing energy storage circuits (such as DC-link buffering), use the minimum capacitance value (5440µF) for worst-case sag calculations to ensure your circuit remains within safe operating limits. For ripple filtering, use the minimum value to size the capacitor conservatively. If your design requires tighter capacitance accuracy (e.g., within ±10%), you may need to source hand-selected or tighter-tolerance components, which typically increase cost and lead time. Alternatively, parallel multiple 381LQ682M080K052 units to reduce the statistical tolerance effect and improve reliability through redundancy.
• What is the snap-in mounting mechanism of the 381LQ682M080K052, and are there compatibility issues with PCBs designed for solder-tab or twist-lock alternatives? The 381LQ682M080K052 uses a radial, can-style snap-in mounting with through-hole leads spaced 10.00mm (0.394") apart. The snap-in design allows the capacitor to be mechanically retained in the PCB during reflow soldering without requiring mechanical clips or solder tabs. This design is incompatible with PCBs designed for twist-lock (polarized lug connectors) or direct solder-tab interfaces. If your PCB uses alternative mounting schemes, direct substitution is not possible without footprint modification. The snap-in mechanism provides mechanical stability in high-vibration environments (such as industrial or automotive) but may require careful insertion force control during assembly to avoid damaging the leads. Confirm your PCB layout supports the 30mm diameter can body and verify clearance above and below the board for component insertion and wave-soldering access.
• Can the 381LQ682M080K052 be used in DC-link filtering for three-phase industrial motor drives, and what ripple current margin should be maintained? The 381LQ682M080K052 can be used in industrial motor drive DC-link applications given its 80V rating and 2000-hour 105°C lifetime specification. However, DC-link ripple current in three-phase drives typically contains 100Hz and 120Hz components (for 50Hz and 60Hz mains respectively) superimposed on higher-frequency switching ripple. The capacitor's ripple current ratings are 3.9A @ 120Hz and 4.49A @ 20kHz; the actual ripple current in your drive depends on motor load, topology, and switching frequency. Design practice typically applies a 40-50% margin to rated ripple current to account for temperature derating and aging. If your calculated ripple current exceeds 2.0A @ 120Hz, consider paralleling multiple 381LQ682M080K052 units or upgrading to a higher-current-rated capacitor. Additionally, monitor case temperature during commissioning—if the capacitor body exceeds 80°C under normal operation, reduce current load or improve thermal management.
• How does the 381LQ682M080K052 compare to the ESMH800VSN682MR50T alternative in terms of size, ESR, and application fit? The ESMH800VSN682MR50T is a higher-voltage alternative (800V vs. 80V) with nominally equivalent 6800µF capacitance. While both are aluminum electrolytic, the 800V rated part will have significantly larger physical dimensions to accommodate the higher dielectric stress, making it unsuitable for space-constrained designs. Additionally, at 80V operating voltage, the 800V-rated ESMH800VSN682MR50T will operate well below its rated voltage, which may result in higher ESR (capacitors designed for higher voltage ratings typically exhibit higher ESR at lower voltages), reducing ripple current capacity and increasing heat dissipation compared to the 381LQ682M080K052. Use the 800V part only if you specifically need 800V capability in a future design revision or if component availability forces substitution; do not use it as a drop-in replacement for cost or performance optimization on an 80V circuit.
• What are the moisture sensitivity and long-term storage requirements for the 381LQ682M080K052? The 381LQ682M080K052 has Moisture Sensitivity Level (MSL) 1 rating, which is the lowest moisture-sensitivity category. This means the capacitor can be stored at ambient temperature and humidity indefinitely without baking or special moisture-controlled packaging. However, aluminum electrolytic capacitors gradually absorb moisture from air during extended storage, which can increase leakage current at power-on. For inventory stored longer than 6-12 months, form the capacitors at rated voltage for several minutes before deploying in critical circuits to re-form the oxide layer. Do not subject the capacitor to condensation or direct water exposure. When receiving parts, inspect the can for corrosion or physical damage, particularly at the lead seams. RoHS3 compliance and REACH status confirm the 381LQ682M080K052 meets environmental regulations for EU and North American markets.
• What is the leakage current specification of the 381LQ682M080K052 at room temperature and 85°C, and how does this affect low-power standby circuit design? The provided datasheet excerpt does not include explicit leakage current values at room temperature or 85°C. Leakage current for aluminum electrolytic capacitors typically increases exponentially with temperature and voltage; for a 6800µF/80V part, leakage current at room temperature is typically 50-200µA and may exceed 1mA at 85°C. Before integrating the 381LQ682M080K052 into low-power standby or long-hold-up circuits, obtain the full datasheet and measure leakage current at your operating temperature to verify it does not exceed your circuit's quiescent current budget. If leakage is excessive for your application, consider complementary technologies such as film or supercapacitors for standby energy storage, or add series discharge resistors to controlled leakage paths. For safety-critical designs, account for leakage current in fault analysis to ensure capacitor discharge paths prevent dangerous voltages during shutdown.
• Is the 381LQ682M080K052 appropriate for audio output filtering, or should a capacitor with lower distortion characteristics be selected? The 381LQ682M080K052 is a general-purpose aluminum electrolytic capacitor with 41mOhm ESR @ 120Hz, which is relatively high for audio applications. Audio-grade designs typically employ low-ESR electrolytic or specialized film capacitors (with ESR <10mOhm) in signal paths to minimize harmonic distortion and preserve transient detail. The 381LQ682M080K052 is better suited to power supply filtering in audio amplifiers rather than signal-path filtering. If you are designing the output filter stage of a Class D amplifier or feedback network where capacitor ESR and dielectric absorption affect audio quality, evaluate specialized low-ESR or film alternatives. If your application is only power supply DC-link filtering far from the audio signal path, the 381LQ682M080K052's ESR is acceptable, though temperature stability of capacitance over the audio frequency range should be verified.
• Can the 381LQ682M080K052 handle reverse-polarity transients or negative voltage spikes without failure? Aluminum electrolytic capacitors, including the 381LQ682M080K052, are polarized components and can be severely damaged by reverse voltage or negative transients. Applying even a few volts of reverse polarity can rupture the oxide dielectric, causing catastrophic failure, internal short circuits, and potential venting or explosion if the capacitor is sealed. The 381LQ682M080K052 is not designed to withstand reverse voltage. If your circuit may experience polarity reversal (such as in automotive or industrial environments with fault conditions), add protective diodes in parallel with reverse-bias orientation to clamp negative transients to safe levels (typically -0.7V for silicon diodes). Alternatively, use specially rated non-polarized capacitors or film technology if polarity protection is impractical. During commissioning, verify correct polarity of all capacitors before initial power-up, and implement circuit-level protection to prevent transient reversal from battery disconnection or power sequencing faults.
• What is the RoHS3 compliance status of the 381LQ682M080K052 and are there any restricted substances or material declarations needed for end products? The 381LQ682M080K052 is confirmed RoHS3 compliant, meaning it meets the Restriction of Hazardous Substances Directive (RoHS 3 or 2011/65/EU as amended) and does not contain prohibited substances including lead, cadmium, mercury, hexavalent chromium, polybrominated biphenyls (PBB), or polybrominated diphenyl ethers (PBDE) above specified thresholds. The part is also REACH unaffected, indicating it does not contain Substances of Very High Concern (SVHCs) on the REACH candidate list at reportable concentrations. For end-product compliance (CE marking, FCC, or similar), no additional material declarations are required for the capacitor itself. However, verify that the complete assembly (PCB, solder, other components) also meets applicable directives. Maintain the Certificate of Compliance (CoC) or Material Declaration (MD) from the distributor or manufacturer for audit purposes if your product is subject to regulatory verification.
• How does component aging affect the ripple current capacity of the 381LQ682M080K052 over its 2000-hour rated lifetime at 105°C? As the 381LQ682M080K052 ages at elevated temperature, the electrolyte composition gradually changes, capacitance decreases (typically 5-20% over lifetime), and ESR increases (sometimes doubling by end-of-life). These changes reduce the effective ripple current capacity because higher ESR means more heat is generated at the same ripple current level (P = I²R increases). A capacitor rated for 3.9A @ 120Hz at beginning-of-life may effectively handle only 2.5-3.0A after 2000 hours at 105°C while maintaining acceptable temperature rise. In reliability-critical applications (industrial UPS, power supplies with multi-year MTBF targets, or redundant systems), apply an additional 30-40% ripple current derating beyond the nameplate rating to account for aging. Perform thermal modeling using both beginning-of-life (BoL) and end-of-life (EoL) ESR values to ensure the capacitor does not exceed safe temperature limits across its entire service lifetime.
• What are the electromagnetic compatibility (EMI) and high-frequency filtering characteristics of the 381LQ682M080K052 compared to film or ceramic alternatives? The 381LQ682M080K052 is an aluminum electrolytic capacitor with relatively high ESR (41mOhm @ 120Hz) and significant parasite inductance due to its through-hole radial leads. This makes it a poor choice for high-frequency EMI filtering or noise suppression above a few hundred kilohertz. For effective EMI filtering, ceramic or film capacitors with lower ESR and inductance should be used in parallel with the 381LQ682M080K052 or in place of it in filtering networks. The 381LQ682M080K052 is appropriate for low-frequency bulk capacitance and energy storage but not for suppressing switching noise or compliance with conducted emission standards. If your power supply design requires multi-stage filtering (e.g., bulk electrolytic + film + ceramic in descending capacitance values), the 381LQ682M080K052 serves as the bulk stage; add lower-capacitance, lower-ESR film or ceramic stages close to noise-sensitive circuits to meet EMI requirements.