Littelfuse 0451.200MRSN Surface Mount Board Fuse - Equivalent & Substitute Parts

Part Overview

The Littelfuse 0451.200MRSN is a 200 mA, 125 V AC surface mount board fuse in the NANO²® 451 series. This fast-blow fuse is designed for board-level protection in 2-SMD, square end block configuration. The part is currently active in production with full inventory availability. Substitute parts are identified to provide alternative sourcing options when the primary part number is unavailable or when design flexibility permits component selection from equivalent electrical and mechanical specifications.

Substiute Parts

0451.200MRSN

Littelfuse Inc.In Stock: 10690451.200MRSN Datasheet

Current PartRFQ

0448.200MR

Littelfuse Inc.In Stock: 26850448.200MR Datasheet

Parametric EquivalentRFQ

0451.200MRL

Littelfuse Inc.In Stock: 349530451.200MRL Datasheet

Parametric EquivalentRFQ

0453.200MR

LittelfuseIn Stock: 23700453.200MR Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 0451.200MRSN are qualified based on the following critical parameters that must match or be compatible with the main part:

• Current Rating: 200 mA (exact match required)
• Voltage Rating - AC: 125 V (exact match required)
• Response Time: Fast Blow (exact match required)
• Package / Case: 2-SMD, Square End Block (exact match required)
• Mounting Type: Surface Mount (exact match required)
• Size / Dimension: 0.240" L x 0.106" W x 0.106" H (exact match required)
• Breaking Capacity @ Rated Voltage: 50A (exact match required)
• Operating Temperature Range: -55°C ~ 125°C (exact match required)
• RoHS Status: ROHS3 Compliant (exact match required)
• Moisture Sensitivity Level: 1 (Unlimited) (exact match required)

The three substitute parts listed below meet all critical electrical and mechanical parameters. Variations in DC voltage rating, melting I²t, DC cold resistance, and approval agency certifications are noted but do not preclude substitution when AC-only operation is specified.

Parameter Comparison

Engineering Selection Recommendations

All three substitute parts are active products from Littelfuse with full regulatory compliance. Selection among these parts is based on the following considerations:

0451.200MRL is the closest functional equivalent to the 0451.200MRSN, sharing the same NANO²® 451 series designation, melting I²t value (0.0089), and DC cold resistance (0.8372 Ohms). This part adds DC voltage rating specification (125 V DC) and carries UL certification in addition to CSA approval. This part is recommended as the primary substitute when the 0451.200MRSN is unavailable.

0453.200MR is functionally equivalent to the 0451.200MRSN with identical melting I²t (0.0089) and DC cold resistance (0.8372 Ohms). It belongs to the NANO²® 453 series and carries CSA and UL certifications. This part provides an alternative from a different product series within the NANO²® family.

0448.200MR belongs to the NANO²® 448 series and differs in melting I²t (0.0038 versus 0.0089) and DC cold resistance (1.4 Ohms versus 0.8372 Ohms). While electrically compatible for AC 125 V operation at 200 mA, the thermal characteristics differ. This part carries CSA and UL certifications and includes explicit DC voltage rating (125 V DC).

All parts are ROHS3 compliant, MSL Level 1, and operate across the -55°C to 125°C temperature range. Selection should be based on design requirements for thermal response characteristics and regulatory certification scope.

Frequently Asked Questions (FAQ)

Q: Can the 0451.200MRL be used as a direct replacement for the 0451.200MRSN?

A: Yes. Both parts share identical current rating (200 mA), AC voltage rating (125 V), response time (fast blow), package configuration (2-SMD, square end block), physical dimensions, breaking capacity, melting I²t, DC cold resistance, operating temperature range, and compliance status. The 0451.200MRL adds DC voltage rating specification and UL certification.

Q: What is the difference between the 0448.200MR and the 0451.200MRSN?

A: The 0448.200MR differs in melting I²t (0.0038 versus 0.0089) and DC cold resistance (1.4 Ohms versus 0.8372 Ohms). Both parts meet the same current, voltage, and package requirements. The 0448.200MR includes explicit DC voltage rating (125 V DC) while the 0451.200MRSN does not specify DC rating. Selection depends on whether thermal response characteristics are critical to the application.

Q: Are all substitute parts available in the same packaging format?

A: Yes. All parts listed are supplied in Tape & Reel (TR) packaging, suitable for automated assembly processes.

Q: Do all substitute parts meet the same regulatory requirements?

A: All parts are ROHS3 compliant and MSL Level 1. The 0451.200MRSN carries CSA and UR certifications. The substitute parts (0448.200MR, 0451.200MRL, 0453.200MR) carry CSA and UL certifications. Verify certification scope requirements for your specific application.

Q: Can these parts be used in DC-only applications?

A: The 0451.200MRSN does not specify a DC voltage rating. The substitute parts 0448.200MR, 0451.200MRL, and 0453.200MR all specify 125 V DC rating and are suitable for DC applications at 200 mA.

Q: What determines whether a part can substitute for the 0451.200MRSN?

A: Substitution is determined by matching current rating (200 mA), AC voltage rating (125 V), response time (fast blow), package type (2-SMD, square end block), physical dimensions (0.240" L x 0.106" W x 0.106" H), breaking capacity (50A), operating temperature range (-55°C to 125°C), and compliance status (ROHS3, MSL 1). Variations in melting I²t, DC cold resistance, and certification agencies do not preclude substitution when these core parameters align.