Littelfuse 0673003.DRT4 Equivalent & Substitute Parts

Part Overview

The Littelfuse 0673003.DRT4 is a 3A 250VAC axial glass cartridge fuse designed for through-hole mounting applications. This part is classified as obsolete, making identification of suitable substitutes necessary for ongoing design support and component procurement. The fuse provides slow-blow response characteristics with a 50A breaking capacity at rated voltage and is approved by CSA and UL agencies.

Substiute Parts

0673003.DRT4

Littelfuse Inc.In Stock: 11360673003.DRT4 Datasheet

Current PartRFQ

0875003.MRET1P

Littelfuse Inc.In Stock: 11550875003.MRET1P Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 0673003.DRT4 is based on electrical and mechanical parameter alignment:

Critical Matching Parameters:

• Current Rating: 3 A (exact match required)
• Voltage Rating (AC): 250 V (exact match required)
• Response Time: Slow Blow (exact match required)
• Breaking Capacity @ Rated Voltage: 50 A (exact match required)
• Mounting Type: Through Hole (exact match required)
• Package / Case: Cartridge, Non-Standard (Axial) (exact match required)

The primary substitute, Littelfuse 0875003.MRET1P, meets all critical electrical parameters. The material change from glass to ceramic cartridge construction is permissible within the allowed parameter set, as both materials satisfy the electrical and mechanical requirements for this application category.

Parameter Comparison

Engineering Selection Recommendations

The Littelfuse 0875003.MRET1P is the designated manufacturer substitute for the obsolete 0673003.DRT4. Selection of this substitute is supported by:

• Identical electrical ratings (3A, 250VAC, 50A breaking capacity, slow-blow response)
• Identical mounting configuration (through-hole, axial cartridge)
• Active product status with current manufacturing support
• Enhanced regulatory compliance (ROHS3 Compliant vs. non-compliant)
• cULus approval certification (expanded from CSA/UL)
• Defined operating temperature range (-55°C ~ 125°C)

The dimensional variation (0.142" Dia x 0.394" L vs. 0.154" Dia x 0.433" L) reflects the ceramic cartridge design and remains within acceptable mechanical tolerances for through-hole mounting applications. The lower DC cold resistance (0.0171 Ohms vs. 0.0247 Ohms) and higher melting I²t (24.5 vs. 18.4) are characteristic of ceramic construction and do not affect functional compatibility.

Frequently Asked Questions (FAQ)

Q: Can the 0875003.MRET1P be used as a direct replacement for the 0673003.DRT4?

A: Yes. Both parts share identical electrical specifications (3A, 250VAC, 50A breaking capacity, slow-blow response) and mounting configuration (through-hole, axial cartridge). The substitute is the manufacturer-recommended replacement for the obsolete part.

Q: What is the difference between glass and ceramic cartridge fuses?

A: The 0673003.DRT4 uses glass cartridge construction, while the 0875003.MRET1P uses ceramic construction. Both materials satisfy the electrical and mechanical requirements for this application. Ceramic construction provides enhanced durability and is the current manufacturing standard.

Q: Are there dimensional compatibility concerns?

A: The substitute is slightly smaller (0.142" Dia x 0.394" L vs. 0.154" Dia x 0.433" L). This dimensional difference is acceptable for through-hole mounting applications and does not affect electrical performance or mechanical fit in standard fuse holders designed for axial cartridge fuses.

Q: What is the difference in RoHS compliance?

A: The original part (0673003.DRT4) is RoHS non-compliant. The substitute (0875003.MRET1P) is ROHS3 compliant, meeting current environmental and regulatory standards for electronic components.

Q: Does the substitute have regulatory approvals?

A: Yes. The 0875003.MRET1P carries cULus certification, which encompasses both CSA and UL approvals held by the original part, providing equivalent or expanded regulatory coverage.

Q: What packaging is available for the substitute?

A: The 0875003.MRET1P is supplied in Tape & Reel (TR) packaging, suitable for automated assembly processes. The original part packaging format is not specified in the available data.