LPX681M350H4P3 Equivalent & Substitute Parts

Part Overview

The LPX681M350H4P3 is a 680 µF, 350 V aluminum electrolytic capacitor manufactured by Cornell Dubilier Electronics (CDE) in the LPX series. This radial, can-style snap-in capacitor is designed for general-purpose applications requiring high capacitance and voltage ratings in a compact through-hole package. The part is currently active in production and ROHS3 compliant.

Substitute parts become necessary when the original component reaches end-of-life status, inventory constraints occur, or when design requirements permit operation at higher voltage ratings while maintaining identical capacitance and mechanical compatibility.

Key Parameters

Parameter	Value	Unit	Substitution Relevance
Capacitance	680	µF	Must match exactly
Voltage - Rated	350	V	Substitutes must equal or exceed
Tolerance	±20%	%	Must match
ESR @ 120Hz	293	mOhm	Reference value; substitutes may vary
Lifetime @ 85°C	1000	Hrs	Reference value; substitutes may exceed
Operating Temperature	-40 to 85	°C	Must match or exceed range
Lead Spacing	10.00	mm	Must match for PCB compatibility
Package Type	Radial, Can - Snap-In	—	Must match for mechanical fit
Mounting Type	Through Hole	—	Must match

Substitute Part Grouping Explanation

Substitution eligibility for the LPX681M350H4P3 is determined by the following criteria:

Primary Matching Requirements:

Capacitance: 680 µF (exact match required)
Tolerance: ±20% (exact match required)
Lead Spacing: 10.00 mm (exact match required)
Package Type: Radial, Can - Snap-In (exact match required)
Mounting Type: Through Hole (exact match required)
Operating Temperature Range: -40°C to 85°C (exact match or extended range acceptable)

Secondary Compatibility Parameters:

Voltage Rating: Must equal or exceed 350 V
ESR and Ripple Current: May vary within acceptable operating margins
Lifetime @ 85°C: May equal or exceed 1000 hours
Physical Dimensions: Height may vary within mechanical envelope constraints

Identified Substitutes:

LPX681M400H9P3 (Cornell Dubilier Electronics): Same series, identical capacitance and tolerance, 400 V rating (exceeds 350 V requirement), matching lead spacing and package type. Height increased to 50 mm. Active product status.
B43305B9687M000 (EPCOS - TDK Electronics): Different manufacturer, identical capacitance and tolerance, 400 V rating (exceeds 350 V requirement), matching lead spacing and package type. Height reduced to 40 mm. Product status: Not For New Designs. Superior ESR (200 mOhm) and extended lifetime (2000 hours).

Parameter Comparison

Parameter	LPX681M350H4P3	LPX681M400H9P3	B43305B9687M000
Manufacturer	Cornell Dubilier Electronics	Cornell Dubilier Electronics	EPCOS - TDK Electronics
Capacitance	680 µF	680 µF	680 µF
Tolerance	±20%	±20%	±20%
Voltage - Rated	350 V	400 V	400 V
ESR @ Reference Frequency	293 mOhm @ 120 Hz	293 mOhm @ 120 Hz	200 mOhm @ 100 Hz
Lifetime @ 85°C	1000 Hrs	1000 Hrs	2000 Hrs
Operating Temperature	-40°C to 85°C	-40°C to 85°C	-40°C to 85°C
Lead Spacing	10.00 mm	10.00 mm	10.00 mm
Diameter	35.00 mm	35.00 mm	35.00 mm
Height - Seated (Max)	45.00 mm	50.00 mm	40.00 mm
Package Type	Radial, Can - Snap-In	Radial, Can - Snap-In	Radial, Can - Snap-In
Mounting Type	Through Hole	Through Hole	Through Hole
Product Status	Active	Active	Not For New Designs
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

LPX681M400H9P3 (Recommended Primary Substitute):

This part is the preferred substitute for the LPX681M350H4P3. Both components are manufactured by Cornell Dubilier Electronics within the same LPX series, ensuring design continuity and supply chain consistency. The LPX681M400H9P3 maintains identical electrical specifications (680 µF, ±20% tolerance) and mechanical compatibility (10.00 mm lead spacing, radial snap-in package). The 400 V rating provides a 50 V margin above the original 350 V specification, permitting direct substitution in applications operating at or below 350 V. Both parts are ROHS3 compliant and carry active product status, ensuring long-term availability and manufacturing support.

The height difference (50 mm versus 45 mm) requires verification of available PCB clearance in the vertical direction. This part is suitable for new designs and ongoing production.

B43305B9687M000 (Alternative Substitute):

This EPCOS - TDK Electronics part meets all primary substitution criteria: 680 µF capacitance, ±20% tolerance, 400 V rating, 10.00 mm lead spacing, and radial snap-in package configuration. The component offers superior electrical performance with lower ESR (200 mOhm @ 100 Hz versus 293 mOhm @ 120 Hz) and extended lifetime (2000 hours @ 85°C versus 1000 hours @ 85°C).

However, this part carries a "Not For New Designs" product status designation. Use of B43305B9687M000 is restricted to legacy system maintenance, repair operations, or applications where existing inventory must be consumed. The reduced height (40 mm) provides improved PCB clearance compared to the original part.

Compliance and Regulatory Status:

All three parts are ROHS3 compliant, REACH unaffected, and classified under ECCN EAR99 and HTSUS 8532.22.0040. No regulatory barriers exist for substitution within the specified applications.

Frequently Asked Questions (FAQ)

Q: Can LPX681M400H9P3 be used as a direct replacement for LPX681M350H4P3?

A: Yes. The LPX681M400H9P3 is electrically and mechanically compatible. Both parts share identical capacitance (680 µF), tolerance (±20%), lead spacing (10.00 mm), and package type (radial snap-in). The 400 V rating of the substitute exceeds the 350 V requirement, permitting operation in any circuit designed for the original part. Verify available PCB height clearance, as the substitute is 5 mm taller (50 mm versus 45 mm).

Q: What is the difference between the two Cornell Dubilier parts?

A: LPX681M350H4P3 and LPX681M400H9P3 differ only in voltage rating (350 V versus 400 V) and physical height (45 mm versus 50 mm). All other electrical and mechanical parameters are identical. Both parts are active products from the same manufacturer.

Q: Why is B43305B9687M000 marked "Not For New Designs"?

A: The B43305B9687M000 carries a legacy product status from EPCOS - TDK Electronics. This designation indicates the part is no longer recommended for incorporation into new circuit designs. However, the part remains available for repair, maintenance, and replacement of existing systems. For new product development, use LPX681M400H9P3 or equivalent active-status alternatives.

Q: Are there height restrictions when substituting these parts?

A: Yes. The original LPX681M350H4P3 has a maximum seated height of 45 mm. The LPX681M400H9P3 substitute is 50 mm tall, requiring 5 mm additional vertical clearance. The B43305B9687M000 is 40 mm tall, providing improved clearance. Verify PCB layout and component placement constraints before substitution.

Q: Do all three parts have identical lead spacing?

A: Yes. All three parts feature 10.00 mm lead spacing and are compatible with PCB footprints designed for the LPX681M350H4P3. No PCB redesign is required for lead-to-pad alignment.

Q: What is the significance of ESR differences between these parts?

A: ESR (Equivalent Series Resistance) affects ripple current handling and thermal performance. The B43305B9687M000 exhibits lower ESR (200 mOhm @ 100 Hz) compared to both CDE parts (293 mOhm @ 120 Hz), resulting in reduced heat generation under ripple current conditions. This performance advantage is offset by the part's legacy status. For applications with high ripple current requirements, the lower ESR of B43305B9687M000 may provide operational benefits.

Q: Can these parts be used interchangeably in existing assemblies?

A: LPX681M400H9P3 can be used interchangeably with LPX681M350H4P3 in existing assemblies, provided PCB height clearance is available. B43305B9687M000 is mechanically compatible but should be reserved for repair and maintenance applications due to its "Not For New Designs" status. Consult design documentation and supply chain requirements before implementing substitutions in production assemblies.

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