Littelfuse 0453.250MR Surface Mount Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 0453.250MR is a 250 mA, 125 V AC/DC surface mount board fuse in the NANO²® 453 series. This fast-blow fuse is designed for circuit protection in compact 2-SMD, square end block packages. The part is active in production with full CSA and UL approval certifications. Equivalent and substitute parts are identified to support design flexibility, supply chain continuity, and component availability across manufacturing environments.

Key Parameters

Parameter	Value
Current Rating	250 mA
Voltage Rating (AC)	125 V
Voltage Rating (DC)	125 V
Response Time	Fast Blow
Mounting Type	Surface Mount
Package / Case	2-SMD, Square End Block
Breaking Capacity @ Rated Voltage	50 A
Operating Temperature Range	-55°C to 125°C
Size / Dimension	0.240" L x 0.106" W x 0.106" H (6.10mm x 2.69mm x 2.69mm)
Approval Agencies	CSA, UL
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility for the 0453.250MR is determined by strict equivalence across the following critical parameters:

Current Rating: 250 mA (exact match required)
Voltage Rating: 125 V AC and 125 V DC (exact match required)
Response Time: Fast Blow (exact match required)
Mounting Type: Surface Mount (exact match required)
Package / Case: 2-SMD, Square End Block (exact match required)
Breaking Capacity @ Rated Voltage: 50 A (exact match required)
Operating Temperature Range: -55°C to 125°C (exact match required)
Approval Agencies: CSA and/or UL certification (required for regulatory compliance)

All identified substitute parts meet these criteria. Littelfuse parts 0448.250MR, 0451.250MRL, and 0451.250NRL are parametric equivalents within the NANO²® fuse family. The Bourns SF-2410FP025T-2 is a direct manufacturer equivalent from an alternative supplier, meeting identical electrical and mechanical specifications.

Parameter Comparison

Parameter	0453.250MR (Main)	0448.250MR	0451.250MRL	0451.250NRL	SF-2410FP025T-2
Manufacturer	Littelfuse Inc.	Littelfuse Inc.	Littelfuse Inc.	Littelfuse Inc.	Bourns Inc.
Series	NANO²® 453	NANO²® 448	NANO²® 451	NANO²® 451	SinglFuse™ SF-2410FP-T
Current Rating (Amps)	250 mA	250 mA	250 mA	250 mA	250 mA
Voltage Rating - AC	125 V	125 V	125 V	125 V	125 V
Voltage Rating - DC	125 V	125 V	125 V	125 V	125 V
Response Time	Fast Blow	Fast Blow	Fast Blow	Fast Blow	Fast Blow
Package / Case	2-SMD, Square End Block	2-SMD, Square End Block	2-SMD, Square End Block	2-SMD, Square End Block	2-SMD, Square End Block
Breaking Capacity @ Rated Voltage	50 A	50 A	50 A	50 A	50 A
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Operating Temperature	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C
Size / Dimension	0.240" L x 0.106" W x 0.106" H (6.10mm x 2.69mm x 2.69mm)	0.240" L x 0.106" W x 0.106" H (6.10mm x 2.69mm x 2.69mm)	0.240" L x 0.106" W x 0.106" H (6.10mm x 2.69mm x 2.69mm)	0.240" L x 0.106" W x 0.106" H (6.10mm x 2.69mm x 2.69mm)	0.240" L x 0.102" W x 0.102" H (6.10mm x 2.59mm x 2.59mm)
Approval Agency	CSA, UL	CSA, UL	CSA, UL	CSA, UL	cUL, UL
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)
Product Status	Active	Active	Active	Active	Active

Engineering Selection Recommendations

All substitute parts listed are active production components with full regulatory certifications (CSA, UL, or cUL). Selection among these equivalents may be based on:

Supply availability and inventory levels
Supplier preference and lead time requirements
Existing qualification status within manufacturing processes
Packaging and tape reel specifications (all parts supplied in Tape & Reel format)

The Littelfuse NANO²® series parts (0448.250MR, 0451.250MRL, 0451.250NRL) maintain full compatibility within the Littelfuse product ecosystem. The Bourns SF-2410FP025T-2 provides cross-manufacturer equivalence with identical electrical performance and regulatory compliance.

Frequently Asked Questions (FAQ)

Q: Can the 0448.250MR be used as a direct replacement for the 0453.250MR?

A: Yes. Both parts share identical current rating (250 mA), voltage ratings (125 V AC/DC), response time (fast blow), package type (2-SMD, square end block), and regulatory certifications (CSA, UL). The primary difference is series designation (NANO²® 448 versus NANO²® 453).

Q: What is the difference between the 0451.250MRL and 0451.250NRL?

A: Both parts are from the NANO²® 451 series with identical electrical and mechanical specifications. The designation suffix indicates packaging or tape configuration variants. Both are functionally equivalent for circuit protection applications.

Q: Is the Bourns SF-2410FP025T-2 compatible with designs specified for the Littelfuse 0453.250MR?

A: Yes. The SF-2410FP025T-2 meets all critical electrical parameters (250 mA, 125 V AC/DC, fast blow, 50 A breaking capacity) and mechanical specifications (2-SMD, square end block package, -55°C to 125°C operating range). Both parts carry UL certification. Minor dimensional variation exists (0.102" versus 0.106" width and height), but this does not affect PCB footprint compatibility for standard 2-SMD fuse land patterns.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts are ROHS3 compliant with MSL rating of 1 (unlimited moisture sensitivity level).

Q: What is the breaking capacity specification, and why is it important?

A: Breaking capacity is 50 A at rated voltage for all listed parts. This specification defines the maximum fault current the fuse can safely interrupt without rupturing or creating a hazard. All substitute parts maintain this specification.

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