Equivalent & Substitute Parts for 128LMB250M2EG

Part Overview

The 128LMB250M2EG is a 1200 µF, 250 V aluminum electrolytic capacitor manufactured by Cornell Dubilier / Illinois Capacitor. 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 1030 units in stock. Substitute parts are identified to provide alternative sourcing options when the primary part becomes unavailable or when inventory constraints require component flexibility.

Substiute Parts

128LMB250M2EG

Cornell Dubilier / Illinois CapacitorIn Stock: 1124128LMB250M2EG Datasheet

Current PartRFQ

381LX122M250A452

Cornell Dubilier Electronics (CDE)In Stock: 1762381LX122M250A452 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 128LMB250M2EG is determined by strict equivalence across the following critical parameters:

Mandatory Matching Parameters:

• Capacitance: 1200 µF
• Voltage Rating: 250 V
• Tolerance: ±20%
• Package / Case: Radial, Can - Snap-In
• Lead Spacing: 0.394" (10.00mm)
• Physical Dimensions: 1.378" Dia (35.00mm), Height 1.850" (47.00mm) maximum
• Mounting Type: Through Hole
• Polarization: Polar

Acceptable Variation Parameters:

• Operating Temperature Range: Substitute may have extended lower temperature limit
• Ripple Current Ratings: Substitute values may differ while maintaining functional adequacy
• ESR (Equivalent Series Resistance): Substitute may have unspecified ESR if other electrical parameters are equivalent
• Lifetime @ Temperature: Substitute must meet or exceed 3000 Hrs @ 105°C

The substitute part 381LX122M250A452 meets all mandatory matching criteria and maintains compliance with RoHS3 and REACH requirements.

Parameter Comparison

Engineering Selection Recommendations

Both the 128LMB250M2EG and 381LX122M250A452 are active production parts manufactured by Cornell Dubilier, with full RoHS3 compliance and REACH unaffected status. Selection between these parts is based on the following criteria:

Primary Part (128LMB250M2EG):

• Use when higher ripple current capacity is required (2.85 A @ 120 Hz, 4.1895 A @ 10 kHz)
• Use when ESR specification is critical to circuit performance
• Use when operating temperature range is limited to -25°C minimum

Substitute Part (381LX122M250A452):

• Use when extended low-temperature operation is required (-40°C minimum)
• Use when ripple current requirements are within 2.3 A @ 120 Hz and 3.2 A @ 20 kHz limits
• Use when inventory of primary part is unavailable
• Use when sourcing flexibility from Cornell Dubilier Electronics (CDE) is preferred

Both parts are through-hole mounted with identical physical footprints (1.378" diameter, 1.850" height, 10.00mm lead spacing) and are directly interchangeable in PCB layouts. Both maintain 3000-hour lifetime at 105°C and carry MSL Level 1 (unlimited moisture sensitivity).

Frequently Asked Questions (FAQ)

Q: Can 381LX122M250A452 be used as a direct replacement for 128LMB250M2EG in all applications?

A: The 381LX122M250A452 is a direct substitute for applications where ripple current requirements do not exceed 2.3 A @ 120 Hz or 3.2 A @ 20 kHz. Both parts share identical capacitance (1200 µF), voltage rating (250 V), tolerance (±20%), physical dimensions, and mounting specifications. The substitute part offers extended operating temperature range (-40°C to 105°C versus -25°C to 105°C). Verify ripple current specifications against circuit requirements before substitution.

Q: Are the physical dimensions identical between these two parts?

A: Yes. Both the 128LMB250M2EG and 381LX122M250A452 have identical physical specifications: 1.378" diameter (35.00mm), 1.850" maximum seated height (47.00mm), and 0.394" lead spacing (10.00mm). Both are radial, can-style snap-in packages with through-hole mounting. PCB layouts and mechanical mounting are fully compatible.

Q: What is the difference in ripple current ratings?

A: The 128LMB250M2EG specifies 2.85 A @ 120 Hz and 4.1895 A @ 10 kHz. The 381LX122M250A452 specifies 2.3 A @ 120 Hz and 3.2 A @ 20 kHz. The primary part has higher ripple current capacity. Select the substitute only when circuit ripple current demands are within the lower specifications.

Q: Do both parts have the same compliance certifications?

A: Yes. Both parts are ROHS3 compliant, REACH unaffected, and carry MSL Level 1 (unlimited moisture sensitivity). Both are rated for 3000 hours at 105°C. Compliance documentation is equivalent for both parts.

Q: What is the operating temperature difference?

A: The 128LMB250M2EG operates from -25°C to 105°C. The 381LX122M250A452 operates from -40°C to 105°C. The substitute part extends the lower temperature limit by 15°C, making it suitable for applications requiring enhanced cold-temperature performance.

Q: Is ESR (Equivalent Series Resistance) specified for the substitute part?

A: The 128LMB250M2EG specifies ESR of 207.233 mOhm @ 120Hz. The 381LX122M250A452 does not provide ESR specification in available documentation. If ESR is a critical design parameter, the primary part should be used.