Equivalent & Substitute Parts: 397LMB400M2EE

Part Overview

The 397LMB400M2EE is a 390 µF, 400 V aluminum electrolytic capacitor manufactured by Cornell Dubilier / Illinois Capacitor. This radial, snap-in can type component is designed for general purpose applications requiring high-voltage energy storage and filtering. The product is currently active and available in stock with 826 units in inventory. Substitutes are necessary when primary supplier availability is limited, when higher voltage ratings or extended operational lifetimes are required, or when alternative manufacturers' components meet identical electrical and mechanical specifications.

Substiute Parts

397LMB400M2EE

Cornell Dubilier / Illinois CapacitorIn Stock: 863397LMB400M2EE Datasheet

Current PartRFQ

B43644B5397M000

EPCOS - TDK ElectronicsIn Stock: 2078B43644B5397M000 Datasheet

UpgradeRFQ

LQSW6391MELC35

NichiconIn Stock: 273890LQSW6391MELC35 Datasheet

UpgradeRFQ

381LR391M400A032

Cornell Dubilier Electronics (CDE)In Stock: 1724381LR391M400A032 Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 397LMB400M2EE are classified into two categories based on their electrical and mechanical compliance with the main part specifications:

Upgrade Substitutes: Parts that exceed or match all critical electrical parameters while maintaining identical mechanical form factors. These parts offer enhanced performance characteristics such as higher voltage ratings, lower equivalent series resistance (ESR), or extended operational lifetimes. These are directly interchangeable and provide improved reliability margins.

Parametric Equivalents: Parts that match the critical electrical parameters (capacitance, tolerance, voltage rating, and mechanical dimensions) but may differ in secondary performance characteristics such as ESR or ripple current ratings. These parts are fully compatible for circuit operation.

All substitutes maintain:

• Identical capacitance value: 390 µF
• Identical tolerance: ±20%
• Identical lead spacing: 0.394" (10.00 mm)
• Identical can diameter: 1.378" (35.00 mm)
• Identical can height: 1.457" (37.00 mm)
• Identical package type: Radial, Can - Snap-In
• Identical mounting type: Through Hole
• Voltage rating equal to or greater than 400 V
• RoHS3 compliance

Parameter Comparison

Engineering Selection Recommendations

B43644B5397M000 (EPCOS - TDK Electronics): This upgrade substitute offers a higher voltage rating of 450 V compared to the 400 V specification of the main part, providing additional voltage margin. The extended lifetime rating of 5000 Hrs @ 105°C exceeds the main part's 3000 Hrs specification, delivering improved long-term reliability. The significantly lower ESR of 270 mΩ @ 100 Hz reduces heat dissipation in high-ripple current applications. All mechanical dimensions and lead spacing remain identical, ensuring direct PCB compatibility. ROHS3 compliance is maintained. This part is classified as an upgrade substitute suitable for critical applications requiring enhanced performance margins.

LQSW6391MELC35 (Nichicon): This upgrade substitute maintains a voltage rating of 420 V, exceeding the minimum 400 V requirement by 20 V. Mechanical dimensions, lead spacing, and mounting configuration are identical to the main part. This part supports direct PCB interchange without design modifications. The operating temperature range matches the main part specification. ROHS3 compliance is confirmed. This part is suitable for general-purpose applications where the higher voltage rating provides operational margin.

381LR391M400A032 (Cornell Dubilier Electronics): This parametric equivalent part maintains the exact voltage rating of 400 V and the same manufacturer family lineage (Cornell Dubilier). All critical electrical parameters including capacitance, tolerance, voltage rating, and temperature range align with the main part. The ESR of 340 mΩ @ 120 Hz is lower than the main part's 1.06273 Ω, offering improved performance. Mechanical dimensions, lead spacing, and package configuration are identical. This part is suitable for applications where the main part experiences supply constraints or when the improved ESR characteristics are beneficial.

All three substitute parts are RoHS3 compliant and REACH unaffected, maintaining regulatory compliance with the original specification.

Frequently Asked Questions (FAQ)

Q: What determines if a part can substitute for the 397LMB400M2EE? A: Direct substitution requires matching capacitance (390 µF), tolerance (±20%), lead spacing (10.00 mm), can diameter (35.00 mm), can height (37.00 mm), and package type (Radial, Can - Snap-In). The substitute voltage rating must equal or exceed 400 V, and the mounting type must remain Through Hole for PCB compatibility.

Q: Can I use B43644B5397M000 as a direct replacement without circuit redesign? A: Yes. The B43644B5397M000 maintains identical mechanical dimensions and lead spacing. The 450 V rating provides additional voltage margin compared to the 400 V requirement. The part is fully interchangeable on the PCB without layout modifications.

Q: What is the difference between an upgrade substitute and a parametric equivalent? A: An upgrade substitute exceeds performance specifications while maintaining mechanical compatibility. The B43644B5397M000 and LQSW6391MELC35 are upgrade substitutes with higher voltage ratings. The 381LR391M400A032 is a parametric equivalent, matching all critical specifications and offering improved ESR performance.

Q: Are all substitutes RoHS3 compliant? A: Yes. All substitute parts listed—B43644B5397M000, LQSW6391MELC35, and 381LR391M400A032—are RoHS3 compliant, maintaining regulatory alignment with the original part.

Q: Does the higher voltage rating of substitute parts affect circuit operation? A: No. A higher voltage rating does not affect circuit operation. The capacitor operates normally at its rated or lower voltage levels. The additional voltage margin provides improved reliability and extended operational lifespan in voltage stress scenarios.

Q: What is the significance of ESR difference between the main part and substitutes? A: ESR (Equivalent Series Resistance) affects heat dissipation and frequency response. Lower ESR values indicate reduced resistive losses and lower operating temperature. The 381LR391M400A032 (340 mΩ) and B43644B5397M000 (270 mΩ) both provide lower ESR than the main part (1.06273 Ω), improving performance in high-ripple-current applications.

Q: Can mechanical dimensions vary between the main part and substitutes? A: No. All substitute parts maintain identical mechanical dimensions: 35.00 mm diameter, 37.00 mm seated height, and 10.00 mm lead spacing. This ensures direct PCB fit without mechanical interference or redesign.

Q: Is there an inventory consideration between these parts? A: Yes. Inventory availability varies: 397LMB400M2EE has 826 units, B43644B5397M000 has 2036 units, LQSW6391MELC35 has 273,782 units, and 381LR391M400A032 has 1640 units. Higher inventory levels may indicate broader availability and shorter lead times.

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