397LMX400M2DG Aluminum Electrolytic Capacitor - Equivalent & Substitute Parts

Part Overview

The 397LMX400M2DG is a 390 µF, 400 V aluminum electrolytic capacitor manufactured by Cornell Dubilier / Illinois Capacitor in the LMX series. This radial, can-style snap-in capacitor is designed for general-purpose applications requiring stable performance across extended operating temperatures from -25°C to 105°C with a rated lifetime of 5000 hours at 105°C. The part maintains Active product status with full RoHS3 compliance and REACH unaffected designation.

Substitute parts are identified when equivalent capacitance and tolerance values are maintained while voltage ratings, physical dimensions, and mounting characteristics remain compatible with the original application requirements.

Key Parameters

Parameter	Value
Capacitance	390 µF
Tolerance	±20%
Voltage - Rated	400 V
ESR @ 120Hz	1.0048 Ohm
Lifetime @ Temp.	5000 Hrs @ 105°C
Operating Temperature Range	-25°C ~ 105°C
Ripple Current @ 120 Hz	1.72 A
Ripple Current @ 50 kHz	2.5284 A
Lead Spacing	0.394" (10.00mm)
Diameter	1.181" (30.00mm)
Height - Seated (Max)	1.850" (47.00mm)
Mounting Type	Through Hole
Package / Case	Radial, Can - Snap-In
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility for the 397LMX400M2DG is determined by strict adherence to the following electrical and mechanical parameters:

Critical Matching Parameters:

Capacitance value: 390 µF (exact match required)
Tolerance: ±20% (exact match required)
Polarization: Polar (exact match required)
Lead spacing: 0.394" (10.00mm) (exact match required)
Diameter: 1.181" (30.00mm) (exact match required)
Mounting type: Through Hole, Radial, Can - Snap-In (exact match required)
Operating temperature range: -25°C ~ 105°C (exact match required)
Lifetime rating: 5000 Hrs @ 105°C (exact match required)

Allowable Variation Parameters:

Voltage rating: May be equal to or greater than 400 V
Height (seated max): Allowable variance up to 1.870" (47.50mm)
ESR: Specification provided for reference; substitute parts may have undocumented ESR values
Ripple current: Specification provided for reference; substitute parts may have different ripple current ratings

The ELXS451VSN391MR45S from Chemi-Con qualifies as a substitute based on matching all critical parameters while exceeding the voltage rating to 450 V, which is compatible with 400 V circuit requirements.

Parameter Comparison

Parameter	397LMX400M2DG (Cornell Dubilier)	ELXS451VSN391MR45S (Chemi-Con)	Compatibility
Capacitance	390 µF	390 µF	Match
Tolerance	±20%	±20%	Match
Voltage - Rated	400 V	450 V	Compatible (higher rating)
Lifetime @ Temp.	5000 Hrs @ 105°C	5000 Hrs @ 105°C	Match
Operating Temperature Range	-25°C ~ 105°C	-25°C ~ 105°C	Match
Ripple Current @ 120 Hz	1.72 A	1.7 A	Equivalent
Ripple Current @ 50 kHz	2.5284 A	2.431 A	Equivalent
Lead Spacing	0.394" (10.00mm)	0.394" (10.00mm)	Match
Diameter	1.181" (30.00mm)	1.181" (30.00mm)	Match
Height - Seated (Max)	1.850" (47.00mm)	1.870" (47.50mm)	Compatible (within tolerance)
Mounting Type	Through Hole	Through Hole	Match
Package / Case	Radial, Can - Snap-In	Radial, Can - Snap-In	Match
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	Match
Polarization	Polar	Polar	Match

Engineering Selection Recommendations

Primary Part: 397LMX400M2DG

The 397LMX400M2DG remains the specified component for applications where the exact electrical and mechanical characteristics are required. This part is Active in product status with full RoHS3 compliance and REACH unaffected designation. Current inventory of 745 pieces supports immediate availability.

Substitute Part: ELXS451VSN391MR45S

The ELXS451VSN391MR45S from Chemi-Con is a qualified substitute when the primary part is unavailable. This part maintains identical capacitance, tolerance, operating temperature range, and lifetime specifications. The elevated voltage rating of 450 V provides additional design margin for 400 V applications. Physical dimensions remain compatible with PCB layouts designed for the original part, with a maximum height variance of 0.020" (0.50mm). Both parts maintain RoHS3 compliance and REACH unaffected status. Current inventory of 2736 pieces supports extended availability.

Selection between these parts is based on availability and supply chain requirements rather than electrical performance differences.

Frequently Asked Questions (FAQ)

Q: Can the ELXS451VSN391MR45S replace the 397LMX400M2DG in a 400 V circuit?

A: Yes. The ELXS451VSN391MR45S is rated for 450 V, which exceeds the 400 V requirement. Higher voltage ratings are compatible with lower voltage applications.

Q: Are the physical dimensions identical between these parts?

A: The lead spacing and diameter are identical at 0.394" (10.00mm) and 1.181" (30.00mm) respectively. The height differs by 0.020" (0.50mm), with the substitute part measuring 1.870" (47.50mm) maximum versus 1.850" (47.00mm) for the original. This variance is compatible with standard PCB layouts.

Q: Do both parts have the same capacitance and tolerance?

A: Yes. Both parts are rated at 390 µF with ±20% tolerance, ensuring equivalent electrical performance in the circuit.

Q: What is the operating temperature range for both parts?

A: Both parts operate across -25°C to 105°C with a rated lifetime of 5000 hours at 105°C.

Q: Are there differences in ripple current handling?

A: The ripple current specifications are equivalent between the two parts. At 120 Hz, both handle approximately 1.7 A. At 50 kHz, both handle approximately 2.43-2.53 A.

Q: Do both parts meet RoHS and REACH requirements?

A: Yes. Both the 397LMX400M2DG and ELXS451VSN391MR45S are RoHS3 compliant and REACH unaffected.

Q: What is the lead spacing for these snap-in capacitors?

A: Both parts feature 0.394" (10.00mm) lead spacing, compatible with standard through-hole PCB designs for radial snap-in capacitors.

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