SMP 1 Equivalent & Substitute Parts

Part Overview

The SMP 1 is a board mount fuse manufactured by Bel Fuse Inc., rated for 1A at 600VAC with 2-SMD surface mount packaging. This component is classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing design support and procurement continuity. The SMP series fuse is designed for AC/DC applications requiring reliable overcurrent protection in compact surface mount configurations.

Substiute Parts

SMP 1

Bel Fuse Inc.In Stock: 1129SMP 1 Datasheet

Current PartRFQ

46211000000

LittelfuseIn Stock: 243946211000000 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SMP 1 is determined by the following critical parameters:

• Current Rating: 1A (exact match required)
• Voltage Rating - AC: Minimum 600VAC (equal or higher acceptable)
• Mounting Type: Surface Mount (2-SMD configuration)
• Fuse Type: Board Mount
• Response Time: Slow Blow characteristic
• Compliance: REACH Unaffected, RoHS compliance status

The substitute part 46211000000 (Littelfuse NANO²® 462 series) meets the core functional requirements with equivalent current rating and surface mount packaging. While the AC voltage rating is 350VAC (lower than the original 600VAC specification), this part is listed as a direct substitute in the provided data and maintains compatibility with the 2-SMD board mount form factor.

Parameter Comparison

Engineering Selection Recommendations

The 46211000000 (Littelfuse NANO²® 462) is the designated substitute for the obsolete SMP 1. Selection of this alternative is supported by:

• Active product status ensuring long-term availability and supply chain continuity
• Identical 1A current rating and 2-SMD surface mount configuration
• REACH Unaffected compliance matching the original part
• RoHS3 compliance providing environmental regulatory alignment
• Multiple approval agencies (UL, UMF, VDE) confirming safety certifications
• Operating temperature range of -40°C to 85°C suitable for standard industrial applications

The voltage rating difference (350VAC vs. 600VAC) must be evaluated against specific circuit requirements. Applications operating at or below 350VAC are directly compatible. Applications requiring 600VAC operation require circuit redesign or alternative component selection.

Frequently Asked Questions (FAQ)

Q: Can the 46211000000 be used as a direct drop-in replacement for the SMP 1?

A: The 46211000000 is mechanically and electrically compatible for applications operating at 350VAC or below. The 2-SMD surface mount package and 1A current rating are identical. However, applications requiring 600VAC operation cannot use this substitute without circuit modification.

Q: What is the significance of the voltage rating difference?

A: The SMP 1 is rated for 600VAC while the 46211000000 is rated for 350VAC. Voltage rating determines the maximum voltage at which the fuse can safely interrupt a fault condition. Using a lower-rated fuse in a higher-voltage circuit creates a safety hazard and violates electrical standards.

Q: Are there compliance differences between these parts?

A: Both parts are REACH Unaffected. The 46211000000 carries RoHS3 compliance and certifications from UL, UMF, and VDE, providing broader regulatory coverage than the obsolete SMP 1.

Q: What is the package configuration for both parts?

A: Both parts use 2-SMD (Surface Mount Device) packaging in a square end block configuration, enabling direct PCB mounting without additional mechanical fixtures.

Q: Why is the SMP 1 listed as obsolete?

A: Obsolete status indicates the manufacturer has discontinued production. The Littelfuse NANO²® 462 series represents the current market standard for equivalent 1A board mount surface mount fuses.