397LMB350M2EE Aluminum Electrolytic Capacitor - Equivalent & Substitute Parts

Part Overview

The 397LMB350M2EE is a 390 µF, 350 V aluminum electrolytic capacitor manufactured by Cornell Dubilier / Illinois Capacitor in the LMB series. This radial, can-style snap-in capacitor is designed for general-purpose applications requiring stable capacitance and extended operational life. The part is currently active in production with 716 units in stock.

Substitute parts are identified when equivalent capacitance and tolerance values are maintained while voltage ratings, ESR characteristics, or operational lifetimes may be upgraded. Substitution becomes necessary when the original part number reaches end-of-life status, inventory constraints occur, or enhanced performance specifications are required for system reliability.

Key Parameters

Parameter	Specification
Capacitance	390 µF
Tolerance	±20%
Voltage Rating	350 V
ESR @ 120Hz	1.06 Ohm
Lifetime @ 105°C	3000 Hours
Operating Temperature Range	-25°C to 105°C
Package Type	Radial, Can - Snap-In
Lead Spacing	0.394" (10.00 mm)
Case Diameter	1.378" (35.00 mm)
Height (Seated Max)	1.457" (37.00 mm)
Mounting Type	Through Hole
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution of the 397LMB350M2EE is determined by strict adherence to the following electrical and mechanical parameters:

Mandatory Matching Parameters:

Capacitance: 390 µF (exact match required)
Tolerance: ±20% (exact match required)
Package Type: Radial, Can - Snap-In (exact match required)
Lead Spacing: 0.394" (10.00 mm) (exact match required)
Case Diameter: 1.378" (35.00 mm) (exact match required)
Height (Seated Max): 1.457" (37.00 mm) (exact match required)
Mounting Type: Through Hole (exact match required)
Polarization: Polar (exact match required)

Allowable Upgrade Parameters:

Voltage Rating: May be equal to or greater than 350 V
ESR: May be equal to or lower than 1.06 Ohm @ 120Hz
Lifetime @ 105°C: May be equal to or greater than 3000 Hours
Operating Temperature Range: May be equal to or wider than -25°C to 105°C

All three substitute parts meet these criteria and are therefore electrically and mechanically compatible with the 397LMB350M2EE in through-hole PCB applications.

Parameter Comparison

Parameter	397LMB350M2EE (Main)	381LR391M400A032	B43644B5397M000	LQSW6391MELC35
Manufacturer	Cornell Dubilier / Illinois Capacitor	Cornell Dubilier Electronics (CDE)	EPCOS - TDK Electronics	Nichicon
Series	LMB	381LR	B43644	LQS
Capacitance	390 µF	390 µF	390 µF	390 µF
Tolerance	±20%	±20%	±20%	±20%
Voltage Rating	350 V	400 V	450 V	420 V
ESR @ Frequency	1.06 Ohm @ 120Hz	340 mOhm @ 120Hz	270 mOhm @ 100Hz	Not Specified
Lifetime @ 105°C	3000 Hours	3000 Hours	5000 Hours	3000 Hours
Operating Temperature	-25°C to 105°C	-25°C to 105°C	-40°C to 105°C	-25°C to 105°C
Ripple Current @ 120Hz	1.4 A	1.85 A	1.8 A @ 100Hz	1.61 A
Lead Spacing	0.394" (10.00 mm)	0.394" (10.00 mm)	0.394" (10.00 mm)	0.394" (10.00 mm)
Case Diameter	1.378" (35.00 mm)	1.378" (35.00 mm)	1.378" (35.00 mm)	1.378" (35.00 mm)
Height (Seated Max)	1.457" (37.00 mm)	1.457" (37.00 mm)	1.457" (37.00 mm)	1.457" (37.00 mm)
Package Type	Radial, Can - Snap-In	Radial, Can - Snap-In	Radial, Can - Snap-In	Radial, Can - Snap-In
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Product Status	Active	Active	Active	Active

Engineering Selection Recommendations

All three substitute parts are active products with ROHS3 compliance and REACH unaffected status, meeting current regulatory requirements for industrial and commercial applications.

381LR391M400A032 (Cornell Dubilier Electronics): This substitute provides a 50 V voltage rating upgrade (400 V vs. 350 V) while maintaining identical capacitance, tolerance, and physical dimensions. ESR is reduced to 340 mOhm, improving thermal performance. Ripple current capacity increases to 1.85 A at 120 Hz. Lifetime remains at 3000 hours at 105°C. This part is suitable for applications requiring enhanced voltage margin with equivalent thermal characteristics.

B43644B5397M000 (EPCOS - TDK Electronics): This substitute offers the highest voltage rating at 450 V with the lowest ESR specification at 270 mOhm at 100 Hz. Operational lifetime extends to 5000 hours at 105°C, providing extended service life. Operating temperature range expands to -40°C to 105°C. This part is appropriate for demanding applications requiring superior thermal performance and extended operational life.

LQSW6391MELC35 (Nichicon): This substitute provides a 420 V voltage rating upgrade with maintained 3000-hour lifetime at 105°C. Ripple current capacity is 1.61 A at 120 Hz. ESR specification is not provided in available documentation. This part offers moderate voltage upgrade with standard thermal characteristics.

All substitutes maintain identical physical footprints and through-hole mounting compatibility with the original 397LMB350M2EE design.

Frequently Asked Questions (FAQ)

Q: Can the 381LR391M400A032 be used as a direct replacement for the 397LMB350M2EE?

A: Yes. The 381LR391M400A032 maintains identical capacitance (390 µF), tolerance (±20%), physical dimensions (35.00 mm diameter, 37.00 mm height, 10.00 mm lead spacing), and mounting type (through-hole, radial snap-in). The 400 V rating is compatible with circuits designed for 350 V operation. ESR is improved at 340 mOhm versus 1.06 Ohm.

Q: What is the primary difference between the B43644B5397M000 and the other substitutes?

A: The B43644B5397M000 provides the highest voltage rating (450 V), lowest ESR (270 mOhm), and longest operational lifetime (5000 hours at 105°C). It also supports the widest operating temperature range (-40°C to 105°C). These specifications represent performance upgrades across multiple parameters.

Q: Are all substitute parts RoHS compliant?

A: Yes. All three substitute parts—381LR391M400A032, B43644B5397M000, and LQSW6391MELC35—are ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory standards.

Q: Do the substitute parts fit the same PCB footprint as the 397LMB350M2EE?

A: Yes. All substitute parts share identical physical specifications: 1.378" (35.00 mm) case diameter, 1.457" (37.00 mm) seated height, and 0.394" (10.00 mm) lead spacing. They are designed for through-hole mounting in the same PCB layout.

Q: Which substitute part has the lowest equivalent series resistance?

A: The B43644B5397M000 has the lowest ESR at 270 mOhm measured at 100 Hz, compared to 340 mOhm for the 381LR391M400A032 and 1.06 Ohm for the original 397LMB350M2EE. Lower ESR reduces heat generation and improves thermal performance.

Q: Can I use a higher voltage-rated capacitor in place of the 397LMB350M2EE?

A: Yes. All substitute parts feature voltage ratings equal to or greater than the original 350 V specification. Higher voltage ratings provide additional safety margin and are electrically compatible with circuits designed for the original part.

Q: What is the inventory availability of these substitute parts?

A: The 397LMB350M2EE has 716 units in stock. The 381LR391M400A032 has 1,640 units available. The B43644B5397M000 has 2,036 units available. The LQSW6391MELC35 has 273,782 units in stock, providing the highest availability.

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