LQSW6391MELB40 Equivalent & Substitute Parts

Part Overview

The LQSW6391MELB40 is a 390 µF, 420 V aluminum electrolytic capacitor manufactured by Nichicon in the LQS series. This radial, can-style snap-in capacitor is designed for general-purpose applications requiring high voltage energy storage and filtering. With a rated lifetime of 3000 hours at 105°C and an operating temperature range of -25°C to 105°C, this component serves as a standard solution in power supply circuits and industrial equipment. The part is currently active in production with ROHS3 compliance and substantial inventory availability.

Equivalent and substitute parts are identified when design requirements change, original inventory becomes unavailable, or performance improvements are needed while maintaining mechanical and electrical compatibility within the same application context.

Substiute Parts

LQSW6391MELB40

NichiconIn Stock: 274117LQSW6391MELB40 Datasheet

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ELHS451VSN391MR40S

Chemi-ConIn Stock: 1391ELHS451VSN391MR40S Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the LQSW6391MELB40 is determined by the following critical parameters:

Mandatory Compatibility Criteria:

• Capacitance value: 390 µF (exact match required)
• Tolerance: ±20% (matching specification)
• Package configuration: Radial, Can - Snap-In (mechanical fit requirement)
• Lead spacing: 0.394" (10.00 mm) (PCB footprint compatibility)
• Physical dimensions: Diameter 1.181" (30.00 mm), Height 1.654" (42.00 mm) maximum (board space constraint)
• Mounting type: Through Hole (assembly process compatibility)
• Polarization: Polar (circuit requirement)

Allowable Variation Parameters:

• Voltage rating: May be equal to or higher than 420 V (derating acceptable)
• Operating temperature range: May be equal to or wider than -25°C ~ 105°C
• Lifetime @ temperature: May be equal to or greater than 3000 Hrs @ 105°C
• Ripple current ratings: May be equal to or greater than specified values
• Manufacturer: Different manufacturers acceptable if all above criteria met
• RoHS/REACH compliance: Must maintain or exceed current compliance status

The ELHS451VSN391MR40S from Chemi-Con qualifies as a substitute because it maintains identical capacitance, tolerance, package type, lead spacing, and physical dimensions while offering improved voltage rating (450 V vs. 420 V), extended lifetime (5000 Hrs vs. 3000 Hrs), and wider operating temperature range (-40°C ~ 105°C vs. -25°C ~ 105°C).

Parameter Comparison

Engineering Selection Recommendations

LQSW6391MELB40 (Nichicon LQS Series):

• Primary selection when original part specification is required
• Active product status with established supply chain
• ROHS3 compliance suitable for regulated markets
• Appropriate for applications with 420 V nominal operating voltage and standard thermal cycling requirements

ELHS451VSN391MR40S (Chemi-Con LHS Series):

• Direct substitute when improved performance margins are acceptable
• Higher voltage rating (450 V) provides additional safety margin in 420 V applications
• Extended lifetime rating (5000 Hrs @ 105°C vs. 3000 Hrs) improves system reliability
• Wider operating temperature range (-40°C lower bound) extends application scope
• RoHS compliant status maintains regulatory requirements
• Physical height increase of 0.019" (0.50 mm) requires verification of available board space
• Both parts maintain identical electrical characteristics for capacitance and tolerance
• Both parts maintain identical mechanical footprint for lead spacing and diameter

Selection between these parts should be based on available board clearance for the 0.50 mm height difference and supply chain preferences, as electrical and mechanical compatibility is confirmed.

Frequently Asked Questions (FAQ)

Q: Can ELHS451VSN391MR40S replace LQSW6391MELB40 in existing designs?

A: Yes, provided board layout accommodates the 0.019" (0.50 mm) additional height. All electrical parameters, capacitance value, tolerance, lead spacing, and mounting type are compatible. The substitute part offers improved voltage rating and lifetime performance.

Q: What is the significance of the voltage rating difference (420 V vs. 450 V)?

A: The ELHS451VSN391MR40S is rated for 450 V, which is 30 V higher than the LQSW6391MELB40 at 420 V. In a 420 V application, the substitute operates at a lower stress level, improving reliability and thermal performance. This is an acceptable substitution direction.

Q: Are there any compliance differences between these parts?

A: Both parts are RoHS compliant and REACH unaffected. The LQSW6391MELB40 carries ROHS3 certification, while the ELHS451VSN391MR40S carries standard RoHS certification. Both meet current regulatory requirements for electronic components.

Q: How do the ripple current ratings compare?

A: The ELHS451VSN391MR40S has slightly higher ripple current ratings at both 120 Hz (1.63 A vs. 1.61 A) and 50 kHz (2.3309 A vs. 2.3023 A). This indicates improved thermal performance and lower internal losses in the substitute part.

Q: What is the practical impact of the 5000 Hrs vs. 3000 Hrs lifetime rating?

A: The ELHS451VSN391MR40S is rated for 5000 hours at 105°C compared to 3000 hours for the LQSW6391MELB40. This extended lifetime indicates longer expected service life in high-temperature operating conditions, reducing failure risk in long-duration applications.

Q: Is the 0.50 mm height difference critical for PCB layout?

A: The height difference must be evaluated against available clearance in the specific application. If the design has tight vertical constraints or proximity to other components, the additional 0.50 mm may require layout verification. In most industrial applications with standard board spacing, this difference is accommodated without redesign.

Q: Can LQSW6391MELB40 be used as a substitute for ELHS451VSN391MR40S?

A: No. While mechanically compatible, the LQSW6391MELB40 has a lower voltage rating (420 V vs. 450 V) and shorter lifetime (3000 Hrs vs. 5000 Hrs). Substituting a lower-rated part for a higher-rated specification is not recommended and may compromise system performance.