Littelfuse 37201250431 Board Mount Fuse - Equivalent & Substitute Parts

Part Overview

The Littelfuse 37201250431 is a 125 mA, 250 V AC board mount fuse in the TR5® 372 series, designed for through-hole radial mounting applications. This slow-blow fuse is actively produced and widely stocked, with 1006 units available. Board mount fuses of this specification are essential components in power distribution and circuit protection applications where reliable overcurrent protection is required across industrial, consumer, and commercial equipment.

Alternative equivalent parts may be required due to supply chain constraints, design revisions, or specific application requirements that demand different electrical or mechanical characteristics within the same functional category.

Substiute Parts

37201250431

Littelfuse Inc.In Stock: 103937201250431 Datasheet

Current PartRFQ

37201250411

Littelfuse Inc.In Stock: 387837201250411 Datasheet

DirectRFQ

37401250410

Littelfuse Inc.In Stock: 216437401250410 Datasheet

Parametric EquivalentRFQ

0034.6606

SCHURTER Inc.In Stock: 16950034.6606 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for board mount fuses is determined by strict alignment of electrical and mechanical parameters. The primary criteria are:

• Current Rating: Must match at 125 mA
• Voltage Rating (AC): Must match at 250 V minimum
• Response Time: Must be Slow Blow
• Mounting Type: Must be Through Hole
• Package / Case: Must be Radial, Can, Vertical configuration
• Physical Dimensions: Must be compatible with PCB footprint requirements
• RoHS Compliance: Must maintain ROHS3 Compliant status

The substitute parts listed below meet these core criteria. Variations in secondary parameters such as breaking capacity, melting I²t, DC cold resistance, and approval agencies reflect different series designs and manufacturing standards but do not affect functional interchangeability within the specified electrical and mechanical constraints.

Parameter Comparison

Engineering Selection Recommendations

37201250411 (Direct Manufacturer Equivalent): This part is the primary equivalent, manufactured by Littelfuse Inc. in the same TR5® 372 series. It shares identical electrical specifications, physical dimensions, and approval certifications with the main part 37201250431. This substitute provides the highest level of functional compatibility and is recommended as the first choice for direct replacement. Inventory availability is higher at 3776 units.

37401250410 (Parametric Equivalent): This Littelfuse part belongs to the TR5® 374 series and maintains the same current rating, voltage rating, and mounting configuration. It differs in breaking capacity (50A versus 35A) and melting I²t (0.044 versus 0.1094), reflecting a different thermal response profile. Approval certifications differ (CSA, cULus versus CCC, cURus, SEMKO, VDE). This part is suitable for applications where the higher breaking capacity and different thermal characteristics are acceptable within the design specification.

0034.6606 (Cross-Manufacturer Equivalent): This SCHURTER Inc. part in the MST 250 series meets all core electrical and mechanical substitution criteria. It provides an additional DC voltage rating of 125 V, making it suitable for dual AC/DC applications. Physical dimensions show a slight height variation (0.335" H versus 0.315" H), which must be verified against PCB footprint constraints. Approval certifications include CCC, cURus, KC, and VDE. Operating temperature range extends to -55°C ~ 125°C, providing broader environmental capability.

All substitute parts maintain active product status and ROHS3 compliance, ensuring continued availability and regulatory alignment.

Frequently Asked Questions (FAQ)

Q: Can 37201250411 be used as a direct replacement for 37201250431?

A: Yes. Both parts are manufactured by Littelfuse Inc. in the TR5® 372 series with identical current rating (125 mA), voltage rating (250 V AC), response time (Slow Blow), mounting type (Through Hole), package configuration (Radial, Can, Vertical), and physical dimensions (0.335" Dia x 0.315" H). Electrical and mechanical compatibility is complete.

Q: What is the difference between 37201250431 and 37401250410?

A: Both parts share the same current rating, voltage rating, response time, and mounting configuration. The 37401250410 belongs to the TR5® 374 series and has a higher breaking capacity (50A versus 35A) and lower melting I²t (0.044 versus 0.1094). These differences reflect different thermal response characteristics and approval standards. Substitution is permissible if the application design accepts these parameter variations.

Q: Can the SCHURTER 0034.6606 replace the Littelfuse 37201250431?

A: The 0034.6606 meets all core substitution criteria: 125 mA current rating, 250 V AC voltage rating, Slow Blow response, Through Hole mounting, and Radial, Can, Vertical package. Physical dimensions show a height difference of 0.020" (0.335" H versus 0.315" H), which must be verified against your PCB footprint. The part includes a 125 V DC rating, making it suitable for AC/DC applications. Substitution is valid if footprint compatibility is confirmed.

Q: Are all substitute parts RoHS compliant?

A: Yes. All listed substitute parts—37201250411, 37401250410, and 0034.6606—are ROHS3 Compliant, matching the compliance status of the main part 37201250431.

Q: What approval certifications should I verify for my application?

A: The main part 37201250431 carries CCC, cURus, SEMKO, and VDE approvals. The direct equivalent 37201250411 shares these certifications. The parametric equivalent 37401250410 carries CSA and cULus approvals. The cross-manufacturer equivalent 0034.6606 carries CCC, cURus, KC, and VDE approvals. Verify that the substitute part's certification set meets your application and regional requirements.

Q: What is the inventory status of each substitute part?

A: 37201250411 has 3776 units in stock, 37401250410 has 2133 units, and 0034.6606 has 1630 units. The main part 37201250431 has 1006 units available.