MQ 4.6 TR Equivalent & Substitute Parts

Part Overview

The MQ 4.6 TR is a 4.6 A board mount axial fuse rated for 125 V AC/DC operation, manufactured by Bel Fuse Inc. This component is classified as obsolete, making identification of equivalent substitute parts essential for ongoing system maintenance and new design implementations. The fast-blow response characteristic and through-hole axial package configuration define its primary application scope in circuit protection applications.

Substiute Parts

MQ 3.5 TR

Bel Fuse Inc.In Stock: 1054MQ 3.5 TR Datasheet

Current PartRFQ

025103.5MXL

Littelfuse Inc.In Stock: 1171025103.5MXL Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the MQ 4.6 TR is determined by strict equivalence across the following critical parameters:

• Current Rating: 4.6 A (exact match required)
• Voltage Rating: 125 V AC and 125 V DC (exact match required)
• Response Time: Fast Blow (exact match required)
• Mounting Type: Through Hole (exact match required)
• Fuse Type: Board Mount, Axial configuration (exact match required)
• Breaking Capacity: 50 A AC, 300 A DC (exact match required)
• Operating Temperature Range: -55°C ~ 125°C (exact match required)

The substitute part 025104.6MXL (Littelfuse Inc., PICO® II 251 series) meets all critical electrical and mechanical parameters. Minor dimensional variations (0.110" Dia vs. 0.125" Dia) and resistance differences (0.024 Ohms vs. 0.027 Ohms) remain within acceptable engineering tolerances for board mount axial fuse applications and do not affect functional equivalence.

Parameter Comparison

Engineering Selection Recommendations

The 025104.6MXL from Littelfuse Inc. serves as the direct functional equivalent for the obsolete MQ 4.6 TR. Selection of this substitute is supported by:

• Identical electrical ratings across current, voltage (AC/DC), and breaking capacity specifications
• Matching fast-blow response characteristic and through-hole axial mounting configuration
• Active product status with established supply chain availability
• Broader regulatory compliance certifications (CSA, cURus, PSE, TUV) compared to the original part
• RoHS3 compliance status, meeting modern environmental and manufacturing standards
• Dimensional compatibility within standard PCB layout tolerances for axial fuse mounting

The minor dimensional reduction (0.110" vs. 0.125" diameter) and improved DC cold resistance (0.024 vs. 0.027 Ohms) present no functional degradation for circuit protection applications. The slightly elevated melting I²t value (1.58 vs. 1.4) remains within acceptable thermal performance parameters for equivalent current ratings.

Frequently Asked Questions (FAQ)

Q: Can the 025104.6MXL be used as a direct replacement for the MQ 4.6 TR on existing PCBs?

A: Yes. Both components share identical electrical specifications (4.6 A, 125 V AC/DC, fast-blow response) and through-hole axial mounting configuration. The dimensional reduction in the 025104.6MXL diameter (0.110" vs. 0.125") does not affect PCB pad compatibility or mechanical fit for standard axial fuse footprints.

Q: What is the significance of the different approval agencies listed for each part?

A: The MQ 4.6 TR carries CE, CSA, and cULus certifications. The 025104.6MXL carries CSA, cURus, PSE, and TUV certifications. Both parts meet North American safety standards (CSA/cULus/cURus). The substitute provides additional international compliance (PSE for Japan, TUV for Europe), expanding its applicability across global markets.

Q: Does the difference in DC cold resistance (0.027 Ohms vs. 0.024 Ohms) affect circuit performance?

A: No. The 0.003 Ohm difference represents a 11% reduction in resistance for the substitute part, which improves electrical efficiency. This variation is negligible in circuit protection applications and does not alter the fuse's protective characteristics or response time.

Q: Why is the melting I²t value different between the two parts?

A: The melting I²t (1.4 vs. 1.58) reflects the thermal energy required to melt the fuse element. Both values correspond to the same 4.6 A current rating and fast-blow response classification. The 12.9% difference is within acceptable manufacturing tolerances for equivalent fuse ratings and does not compromise circuit protection performance.

Q: Is the 025104.6MXL available in the same packaging format as the MQ 4.6 TR?

A: The MQ 4.6 TR is supplied in standard packaging, while the 025104.6MXL is available in bulk packaging. Both components use identical axial through-hole configuration. Packaging format does not affect component functionality or PCB integration.

Q: What compliance advantage does the substitute part offer?

A: The 025104.6MXL is RoHS3 compliant and carries REACH Unaffected status, meeting current environmental regulations. The obsolete MQ 4.6 TR does not carry RoHS certification. For new designs or systems requiring environmental compliance documentation, the substitute is the appropriate selection.