MQ 2TR Equivalent & Substitute Parts Reference

Part Overview

The MQ 2TR is a 2A 125VAC/VDC board mount axial fuse manufactured by Bel Fuse Inc. This component is classified as obsolete, making substitute parts necessary for new designs and ongoing production requirements. The MQ 2TR serves as a fast-blow protection device in through-hole applications with a breaking capacity of 50A AC and 300A DC. Equivalent alternatives from active product lines provide functional continuity while maintaining electrical and mechanical compatibility within specified parameters.

Substiute Parts

MQ 2TR

Bel Fuse Inc.In Stock: 1117MQ 2TR Datasheet

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0251002.NRT1L

Littelfuse Inc.In Stock: 1048180251002.NRT1L Datasheet

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0251002.MXL

Littelfuse Inc.In Stock: 62880251002.MXL Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution for the MQ 2TR is based on strict electrical and mechanical parameter matching:

Primary Substitution Criteria:

• Current Rating: 2 A (exact match required)
• Voltage Rating: 125 V AC / 125 V DC (exact match required)
• Response Time: Fast Blow (exact match required)
• Mounting Type: Through Hole (exact match required)
• Package / Case: Axial (exact match required)
• Breaking Capacity: 50A AC, 300A DC (exact match required)
• Operating Temperature: -55°C ~ 125°C (exact match required)

Substitute Parts Identified:

Both substitute parts from Littelfuse Inc. meet all primary electrical and mechanical criteria. The PICO® II 251 series (part numbers 0251002.NRT1L and 0251002.MXL) are active products with identical current, voltage, response time, and breaking capacity specifications. These parts differ only in packaging format (Cut Tape vs. Bulk) and minor physical dimensions, which remain within acceptable tolerance for board mount applications.

Parameter Comparison

Engineering Selection Recommendations

For Active Production and New Designs:

Use 0251002.NRT1L (Cut Tape packaging) or 0251002.MXL (Bulk packaging) as direct replacements for the obsolete MQ 2TR. Both Littelfuse alternatives are active products with expanded regulatory approvals (CCC, CSA, cURus, PSE, TUV) compared to the original part, and both carry ROHS3 compliance certification.

Packaging Selection:

• 0251002.NRT1L: Specified for tape and reel distribution, suitable for automated assembly processes
• 0251002.MXL: Specified for bulk distribution, suitable for manual assembly or stock applications

Compliance Considerations:

Both substitute parts maintain all critical electrical parameters (2A, 125VAC/VDC, Fast Blow, 50A AC / 300A DC breaking capacity) and operating temperature range (-55°C ~ 125°C). The Littelfuse parts provide enhanced regulatory coverage with additional certifications (CCC, PSE, TUV) and ROHS3 compliance, making them suitable for markets with stricter environmental and safety requirements.

Physical Dimension Note:

The substitute parts have a slightly smaller diameter (0.110" vs. 0.125") while maintaining the same length (0.280"). Verify PCB footprint compatibility before implementation, as the reduced diameter may affect mechanical fit in legacy board designs.

Frequently Asked Questions (FAQ)

Q: Can 0251002.NRT1L and 0251002.MXL be used interchangeably?

A: Yes. Both parts are electrically and mechanically identical, differing only in packaging format. 0251002.NRT1L is supplied in Cut Tape format for automated assembly, while 0251002.MXL is supplied in Bulk format. Selection depends on assembly process requirements, not electrical performance.

Q: What is the difference in melting I²t between the MQ 2TR and the Littelfuse substitutes?

A: The MQ 2TR has a melting I²t of 0.33, while both Littelfuse alternatives (0251002.NRT1L and 0251002.MXL) have a melting I²t of 0.405. This represents a 22.7% increase in thermal energy absorption. Both values remain within the fast-blow response category and maintain identical breaking capacity at rated voltage.

Q: Are there any regulatory compliance differences?

A: The Littelfuse substitutes carry expanded regulatory approvals (CCC, CSA, cURus, PSE, TUV) compared to the MQ 2TR (CE, CSA, cURus). Additionally, the Littelfuse parts are ROHS3 compliant, while the original part does not specify RoHS status. These differences make the substitutes suitable for broader market applications.

Q: Will the smaller diameter of the substitute parts affect PCB compatibility?

A: The substitute parts have a diameter of 0.110" compared to the MQ 2TR's 0.125". The length remains identical at 0.280". PCB footprint compatibility must be verified before implementation, as the reduced diameter may affect mechanical fit in legacy board designs with larger hole specifications.

Q: What is the difference in DC cold resistance?

A: The MQ 2TR has a DC cold resistance of 0.055 Ohms, while the Littelfuse substitutes have 0.0473 Ohms. This 13.9% reduction in resistance may result in slightly lower voltage drop across the fuse element during normal operation, but both values are within acceptable limits for the 2A current rating.

Q: Are the substitute parts suitable for new product designs?

A: Yes. Both 0251002.NRT1L and 0251002.MXL are active products with enhanced regulatory certifications and ROHS3 compliance. They are recommended for new designs requiring 2A, 125VAC/VDC fast-blow protection with through-hole axial mounting.