Littelfuse 46211000000 Surface Mount Fuse - Equivalent & Substitute Parts

Part Overview

The Littelfuse 46211000000 is a 1A 350VAC/350VDC surface mount board fuse in the NANO²® 462 series, designed for circuit protection in electronic applications requiring slow-blow response characteristics. This component is actively manufactured and widely stocked. Substitute parts may be required due to supply constraints, design revisions, or specific application voltage requirements that differ from the original specification.

Substiute Parts

46211000000

LittelfuseIn Stock: 243946211000000 Datasheet

Current PartRFQ

0885001.DR

Littelfuse Inc.In Stock: 49300885001.DR Datasheet

MFR RecommendedRFQ

TR-1245UMFT1-R

Eaton - Electronics DivisionIn Stock: 3840TR-1245UMFT1-R Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the Littelfuse 46211000000 is determined by the following critical parameters:

Mandatory Compatibility Criteria:

• Current Rating: Must be 1 A
• Mounting Type: Must be Surface Mount
• Package / Case: Must be 2-SMD, Square End Block
• Breaking Capacity: Must be 100 A minimum
• Response Time: Must be Slow Blow
• RoHS Compliance: Must be ROHS3 Compliant

Allowable Variation Parameters:

• Voltage Rating (AC/DC): May exceed the original 350V specification, provided the application does not exceed the substitute part's voltage rating
• Operating Temperature Range: May differ; application requirements determine acceptability
• DC Cold Resistance: Minor variations acceptable within engineering tolerance
• Melting I²t: Variations acceptable if within fuse coordination requirements
• Approval Agencies: May differ; application certifications determine acceptability

Two qualified substitute parts meet these criteria with specific voltage and thermal characteristics variations.

Parameter Comparison

Engineering Selection Recommendations

0885001.DR (Littelfuse NANO²® 885 Series)

This substitute is manufacturer-recommended and maintains Littelfuse series continuity. It provides enhanced DC voltage rating (500V) compared to the original 350V specification, making it suitable for applications requiring higher DC voltage margins. Both parts share identical operating temperature range and RoHS3 compliance. The lower melting I²t value (0.8 vs. 2.7) indicates faster thermal response; circuit coordination analysis is required to confirm acceptability in the target application.

TR-1245UMFT1-R (Eaton 1245UMFT Series)

This substitute is manufacturer-recommended and provides extended operating temperature range (-40°C ~ 125°C vs. -40°C ~ 85°C), beneficial for high-temperature environments. AC voltage rating is 250VAC, which is lower than the original 350VAC specification; this part is suitable only for applications operating at or below 250VAC. Melting I²t (2.4) is closer to the original specification (2.7) than the 0885001.DR alternative. RoHS3 compliance and 100A breaking capacity are maintained.

Both substitutes are active products with full inventory availability and meet the mandatory compatibility criteria for current rating, mounting type, package configuration, and breaking capacity.

Frequently Asked Questions (FAQ)

Q: Can the 0885001.DR be used in place of the 46211000000 in all applications?

A: The 0885001.DR is electrically compatible for current rating, mounting, and package. However, the significantly lower melting I²t (0.8 vs. 2.7) means it will respond faster to thermal stress. Applications with inrush currents or transient conditions must be re-evaluated to ensure the substitute does not nuisance-trip. DC voltage rating is higher (500V), which is advantageous for high-voltage circuits.

Q: Is the TR-1245UMFT1-R suitable for 350VAC applications?

A: No. The TR-1245UMFT1-R is rated for 250VAC maximum. It is suitable only for applications operating at 250VAC or lower. For applications requiring 350VAC operation, use the 46211000000 or 0885001.DR.

Q: What is the significance of the different melting I²t values?

A: Melting I²t determines the thermal energy required to melt the fuse element. Lower values indicate faster response to overcurrent. The 0885001.DR (0.8) responds faster than both the original (2.7) and the TR-1245UMFT1-R (2.4). Circuit protection coordination must account for this difference to prevent nuisance operation or inadequate protection.

Q: Are all three parts RoHS3 compliant?

A: Yes. The 46211000000, 0885001.DR, and TR-1245UMFT1-R are all ROHS3 Compliant, meeting environmental and material restriction requirements.

Q: Can these parts be used interchangeably on the same PCB assembly line?

A: Physical compatibility is confirmed: all three parts use 2-SMD, Square End Block packaging and surface mount assembly. However, electrical characteristics differ. Verify that your circuit design accommodates the voltage ratings and melting I²t characteristics of the substitute before implementing line-level substitution.

Q: What approval agencies certify these parts?

A: The 46211000000 carries UL, UMF, and VDE approvals. The 0885001.DR carries cURus and TUV approvals. The TR-1245UMFT1-R carries cURus approval. Confirm that your application's certification requirements are met by the selected substitute.