MQ 750TR Equivalent & Substitute Parts

Part Overview

The MQ 750TR is a 750 mA, 125 V AC/DC board mount axial fuse manufactured by Bel Fuse Inc. This component is classified as obsolete, making identification of equivalent substitute parts essential for ongoing design support and production continuity. The MQ 750TR operates across a temperature range of -55°C to 125°C with fast-blow response characteristics and is approved by CE, CSA, and cURus agencies.

Substiute Parts

MQ 750TR

Bel Fuse Inc.In Stock: 831MQ 750TR Datasheet

Current PartRFQ

0251.750NRT1L

Littelfuse Inc.In Stock: 1915330251.750NRT1L Datasheet

DirectRFQ

0251.750NAT1L

Littelfuse Inc.In Stock: 56550251.750NAT1L Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the MQ 750TR are qualified based on electrical and mechanical parameter equivalence. The critical parameters determining substitutability are:

• Current Rating: 750 mA (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)
• Package / Case: Axial (exact match required)
• Breaking Capacity @ Rated Voltage: 50A AC, 300A DC (exact match required)
• Operating Temperature Range: -55°C ~ 125°C (exact match required)

Both substitute parts listed—0251.750NRT1L and 0251.750NAT1L from Littelfuse Inc.—meet all electrical and mechanical requirements for direct substitution. These components are manufactured under the PICO® II 251 series and maintain active product status, ensuring long-term availability and supply chain reliability.

Parameter Comparison

Engineering Selection Recommendations

Both 0251.750NRT1L and 0251.750NAT1L from Littelfuse Inc. are qualified substitutes for the obsolete MQ 750TR. Selection between these two Littelfuse alternatives should be based on packaging requirements and inventory availability:

• 0251.750NRT1L: Available in Cut Tape (CT) packaging with 191,475 pieces in stock
• 0251.750NAT1L: Available in Cut Tape (CT) packaging with 5,553 pieces in stock

Both parts carry active product status, ensuring continued manufacturing support and supply chain stability. The Littelfuse substitutes provide enhanced compliance certifications (CSA, cURus, TUV) and ROHS3 compliance, exceeding the original MQ 750TR specifications. Physical dimensions differ slightly in diameter (0.110" vs. 0.125"), but both maintain the same 0.280" length and are compatible with standard through-hole board mount applications.

Frequently Asked Questions (FAQ)

Q: Can 0251.750NRT1L and 0251.750NAT1L be used interchangeably with MQ 750TR?

A: Yes. Both Littelfuse parts meet all electrical and mechanical parameters required for direct substitution: 750 mA current rating, 125 V AC/DC voltage rating, fast-blow response, through-hole mounting, and identical breaking capacity specifications.

Q: What is the difference between 0251.750NRT1L and 0251.750NAT1L?

A: Both parts are electrically and mechanically equivalent. The primary difference is packaging format and inventory availability. Both are supplied in Cut Tape (CT) packaging and are part of the PICO® II 251 series.

Q: Are there physical dimension differences that affect board compatibility?

A: The substitute parts have a slightly smaller diameter (0.110" vs. 0.125") but maintain the same 0.280" length. This dimensional difference does not affect through-hole board mount compatibility, as the axial lead spacing and mounting footprint remain functionally equivalent.

Q: Do the substitute parts meet the same compliance standards?

A: The Littelfuse substitutes exceed the original compliance profile. While MQ 750TR carries CE, CSA, and cURus approvals, the 0251.750NRT1L and 0251.750NAT1L carry CSA, cURus, and TUV approvals, plus ROHS3 compliance certification.

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

A: The Melting I²t parameter (0.062 for MQ 750TR vs. 0.153 for substitutes) reflects thermal energy absorption characteristics. Both values are within acceptable ranges for 750 mA fast-blow fuses and do not affect functional substitutability in standard applications.

Q: Are these parts suitable for both AC and DC applications?

A: Yes. All parts are rated for 125 V AC and 125 V DC operation with identical breaking capacity specifications (50A AC, 300A DC), making them suitable for mixed-voltage circuit protection applications.