Littelfuse 046401.6DR Surface Mount Board Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 046401.6DR is a 1.6 A, 250 V AC surface mount board fuse in the NANO²® 464 series, designed for fast-blow protection in compact 2-SMD, square end block packaging. This component is classified as Active product status with full PSE and UMF approvals. Equivalent and substitute parts are identified when design requirements necessitate alternative sourcing, higher voltage ratings, or expanded temperature operating ranges while maintaining core electrical and mechanical compatibility.

Substiute Parts

046401.6DR

Littelfuse Inc.In Stock: 2742046401.6DR Datasheet

Current PartRFQ

TR-1245UMFF1-6-R

Eaton - Electronics DivisionIn Stock: 3897TR-1245UMFF1-6-R Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the Littelfuse 046401.6DR is permissible with the Eaton 1245UMFF1-6-R based on the following alignment of critical electrical and mechanical parameters:

Matching Parameters:

• Current Rating: 1.6 A (identical)
• Response Time: Fast Blow (identical)
• Mounting Type: Surface Mount (identical)
• Package / Case: 2-SMD, Square End Block (identical)
• Breaking Capacity @ Rated Voltage: 100 A (identical)
• Moisture Sensitivity Level: 1 (Unlimited) (identical)

Enhanced Parameters in Substitute:

• Voltage Rating - AC: 350 V (exceeds 250 V requirement)
• Voltage Rating - DC: 250 V (specified; main part unspecified for DC)
• Approval Agency: UL (different certification body; both are recognized standards)

The substitute part maintains all core electrical switching characteristics and physical form factor while providing higher AC voltage margin and explicit DC voltage rating capability.

Parameter Comparison

Engineering Selection Recommendations

Primary Part (046401.6DR - Littelfuse): Select when PSE and UMF certifications are mandatory for the application. This part is suitable for designs operating within -55°C to 125°C and requiring explicit ROHS3 compliance documentation. The lower DC cold resistance (0.0448 Ohms) may be preferred in applications sensitive to resistive heating.

Substitute Part (TR-1245UMFF1-6-R - Eaton): Select when UL certification is acceptable or required. The higher AC voltage rating (350 V vs. 250 V) provides additional safety margin in applications with voltage transients or overvoltage conditions. The explicit 250 V DC rating supports dual-voltage (AC/DC) circuit protection. Consider application requirements if operating temperatures below -40°C are necessary, as this substitute has a narrower low-temperature operating range.

Both parts maintain identical current ratings, response characteristics, and physical form factors, ensuring direct PCB compatibility without layout modifications.

Frequently Asked Questions (FAQ)

Q: Can the Eaton TR-1245UMFF1-6-R directly replace the Littelfuse 046401.6DR on the PCB without modification?

A: Yes. Both parts use identical 2-SMD, square end block packaging with matching physical dimensions (approximately 12 mm length × 4.5 mm width × 4.5 mm height). No PCB layout changes are required for mechanical or electrical fit.

Q: What is the primary difference between these two fuses?

A: The Eaton substitute has a higher AC voltage rating (350 V vs. 250 V) and explicitly specifies a 250 V DC rating. The Littelfuse part is rated 250 V AC only. Both maintain identical 1.6 A current ratings and fast-blow response characteristics.

Q: Are the certifications interchangeable?

A: No. The Littelfuse part carries PSE and UMF approvals, while the Eaton part carries UL approval. Certification requirements depend on the end application and regional regulatory standards. Verify that the substitute's certification meets your design and market requirements before selection.

Q: Does the higher DC cold resistance of the Eaton part affect circuit performance?

A: The Eaton part has 0.058 Ohms versus 0.0448 Ohms for the Littelfuse part. This 0.0132 Ohm difference is negligible in most circuit applications. Applications with extremely tight power budget constraints or high-frequency switching may require detailed thermal analysis to confirm acceptability.

Q: What is the temperature operating range difference?

A: The Littelfuse part operates from -55°C to 125°C, while the Eaton substitute operates from -40°C to 125°C. If your application requires operation below -40°C, the Littelfuse part is required.

Q: Are both parts currently in production?

A: Yes. Both parts have Active product status and are manufactured by their respective suppliers.