CMT3-2-R Equivalent & Substitute Parts

Part Overview

The CMT3-2-R is a 3.5 mH common mode choke manufactured by Eaton - Electronics Division, designed for two-line power line filtering applications. This through-hole component operates at a maximum current rating of 2.6A with a typical DC resistance of 80mOhm and functions across an operating temperature range of -40°C to 125°C. The CMT3-2-R is classified as obsolete, necessitating identification of functionally equivalent substitute components for ongoing design support and procurement requirements.

Substiute Parts

CMT3-2-R

Eaton - Electronics DivisionIn Stock: 826CMT3-2-R Datasheet

Current PartRFQ

EH28-4.0-02-3M5-X

Schaffner EMC Inc.In Stock: 804EH28-4.0-02-3M5-X Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the CMT3-2-R is based on the following critical parameters that must be maintained or exceeded for functional compatibility:

Core Substitution Criteria:

• Filter Type: Power Line (identical)
• Number of Lines: 2 (identical)
• Inductance Value: 3.5 mH (identical nominal value)
• Mounting Type: Through Hole (identical)
• Package / Case: Horizontal, 4 PC Pin (identical)

Allowable Parameter Variations:

• Current Rating: Substitute must equal or exceed 2.6A maximum rating
• DC Resistance: Substitute may be lower than 80mOhm (improved performance)
• Operating Temperature: Substitute range must encompass or exceed -40°C to 125°C
• Physical Dimensions: Substitute dimensions may vary within PCB layout constraints
• Frequency Reference: Inductance measurement frequency may differ (3.5 mH characteristic maintained)

The EH28-4.0-02-3M5-X from Schaffner EMC Inc. satisfies all core substitution criteria and exceeds current rating requirements, making it a direct functional equivalent for the obsolete CMT3-2-R.

Parameter Comparison

Engineering Selection Recommendations

The EH28-4.0-02-3M5-X is the identified equivalent substitute for the obsolete CMT3-2-R based on the following engineering factors:

Functional Equivalence: The substitute maintains identical inductance value (3.5 mH), filter type (Power Line), line configuration (2-line), and mounting architecture (Through Hole, 4 PC Pin horizontal package). These parameters define the core filtering function and circuit integration requirements.

Performance Advantages: The EH28-4.0-02-3M5-X provides a higher current rating (4A versus 2.6A) and lower DC resistance (52mOhm versus 80mOhm typical), resulting in reduced power dissipation and improved thermal performance in the application circuit.

Compliance and Product Status: The EH28-4.0-02-3M5-X is an active product with RoHS3 compliance and REACH unaffected status, ensuring long-term availability and regulatory alignment. The CMT3-2-R obsolete status necessitates transition to this active equivalent.

Design Considerations: Physical dimensions of the substitute are larger (28.00mm x 28.00mm footprint, 23.90mm height versus 25.00mm x 25.00mm and 14.00mm). PCB layout verification is required to confirm fit within available space. The operating temperature range of the substitute (-25°C to 100°C) is narrower than the original part; applications requiring -40°C operation must be evaluated against actual circuit thermal conditions.

Frequently Asked Questions (FAQ)

Q: Can the EH28-4.0-02-3M5-X directly replace the CMT3-2-R without circuit modification?

A: The EH28-4.0-02-3M5-X is functionally equivalent for filtering performance. The identical inductance value, line configuration, and mounting type enable direct electrical substitution. Physical dimensions must be verified against PCB layout constraints due to the larger footprint and height of the substitute component.

Q: What is the significance of the different inductance measurement frequencies (10 kHz versus 400 Hz)?

A: Both components maintain the specified 3.5 mH inductance value at their respective measurement frequencies. The inductance characteristic is equivalent for power line filtering applications. The measurement frequency difference reflects manufacturer test methodology and does not affect functional compatibility in the circuit.

Q: Does the lower DC resistance of the substitute affect circuit operation?

A: The lower DC resistance (52mOhm versus 80mOhm) of the EH28-4.0-02-3M5-X is a performance improvement. Reduced resistance results in lower power dissipation and improved efficiency. No circuit modification is required; the substitute performs identically or better in this parameter.

Q: Is the higher current rating of the substitute (4A versus 2.6A) a concern?

A: The higher current rating is not a concern. The substitute is rated for greater current capacity, providing design margin and thermal headroom. The circuit operates at the same current levels as with the original part; the substitute simply has additional capacity.

Q: What are the physical space implications of using the EH28-4.0-02-3M5-X?

A: The substitute has a larger footprint (28.00mm x 28.00mm versus 25.00mm x 25.00mm) and greater height (23.90mm versus 14.00mm). PCB layout must accommodate these dimensions. If space constraints exist, physical verification against the PCB design is mandatory before component procurement.

Q: Are there any temperature range limitations when using the substitute?

A: The EH28-4.0-02-3M5-X operates from -25°C to 100°C, which is narrower than the CMT3-2-R range of -40°C to 125°C. Applications requiring operation below -25°C or above 100°C must evaluate whether actual circuit thermal conditions remain within the substitute's specified range. Thermal analysis of the specific application is required if extreme temperature operation is necessary.

Q: What is the packaging difference between the two components?

A: The CMT3-2-R is supplied in standard packaging, while the EH28-4.0-02-3M5-X is supplied in tray packaging. Both components use identical through-hole, 4 PC pin horizontal package configuration. Tray packaging is standard for active production components and does not affect electrical or mechanical compatibility.