MQ 5 Equivalent & Substitute Parts

Part Overview

The MQ 5 is a 5A 125VAC/VDC board mount axial fuse manufactured by Bel Fuse Inc. This component is classified as obsolete, making identification of equivalent and substitute parts essential for ongoing system maintenance and new design implementations. The MQ 5 serves as a protective device in electronic circuits requiring fast-blow response characteristics and through-hole mounting configuration.

Substiute Parts

MQ 5

Bel Fuse Inc.In Stock: 975MQ 5 Datasheet

Current PartRFQ

0251005.MXL

Littelfuse Inc.In Stock: 90500251005.MXL Datasheet

DirectRFQ

7010.7130.13

SCHURTER Inc.In Stock: 11057010.7130.13 Datasheet

DirectRFQ

0251005.NRT1L

Littelfuse Inc.In Stock: 1850960251005.NRT1L Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the MQ 5 are classified based on electrical parameter equivalence and mechanical compatibility. The primary substitution criteria are:

• Current Rating: 5 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)
• Breaking Capacity: Minimum 50A AC and 300A DC at rated voltage

Parts are grouped into two categories:

Direct Equivalents (0251005.MXL, 0251005.NRT1L): These Littelfuse PICO® II 251 series fuses maintain identical electrical specifications and axial package configuration. Differences exist only in packaging format (Bulk vs. Cut Tape) and represent the same functional component.

Compatible Substitute (7010.7130.13): The SCHURTER 172322 series fuse meets all electrical requirements but uses a non-standard cartridge axial package with slightly different physical dimensions. This part is mechanically compatible with through-hole board mount applications but requires verification of PCB footprint clearance due to dimensional variations.

Parameter Comparison

Engineering Selection Recommendations

Primary Recommendation: 0251005.MXL or 0251005.NRT1L (Littelfuse PICO® II 251)

The Littelfuse 0251005.MXL and 0251005.NRT1L represent the most direct functional equivalents to the obsolete MQ 5. Both parts maintain identical electrical specifications, response characteristics, and mounting configuration. The distinction between these two parts is packaging format only: 0251005.MXL is supplied in Bulk packaging, while 0251005.NRT1L is supplied in Cut Tape format. Selection between these two should be based on procurement and assembly requirements rather than technical performance. Both parts carry active product status and broader regulatory approvals (CCC, CSA, cURus, PSE, TUV) compared to the original MQ 5.

Secondary Recommendation: 7010.7130.13 (SCHURTER 172322)

The SCHURTER 7010.7130.13 is a compatible substitute that meets all electrical requirements. However, this part differs in physical dimensions and uses a non-standard cartridge axial package. The diameter is reduced from 0.125" to 0.093", and the length is increased from 0.280" to 0.315". These dimensional differences require PCB footprint verification before implementation. Additionally, the operating temperature maximum is limited to 85°C compared to 125°C for the Littelfuse alternatives, which may restrict use in high-temperature applications. The melting I²t value of 6.2 is higher than the original MQ 5 (3.4), indicating different thermal response characteristics.

Frequently Asked Questions (FAQ)

Q: Can I use 0251005.MXL and 0251005.NRT1L interchangeably?

A: Yes. Both parts are electrically and mechanically identical. The only difference is packaging format. 0251005.MXL is supplied in Bulk, while 0251005.NRT1L is supplied in Cut Tape. Selection depends on your procurement and assembly process requirements.

Q: What is the key difference between the Littelfuse and SCHURTER substitutes?

A: The Littelfuse parts (0251005.MXL and 0251005.NRT1L) maintain the same physical dimensions as the original MQ 5 and use standard axial packaging. The SCHURTER 7010.7130.13 uses a non-standard cartridge axial package with different dimensions (smaller diameter, slightly longer length). This requires PCB footprint verification.

Q: Can I use the SCHURTER 7010.7130.13 in a design originally specified for the MQ 5?

A: Electrical substitution is valid. However, mechanical compatibility must be verified. The SCHURTER part has different physical dimensions and a reduced maximum operating temperature (85°C vs. 125°C). PCB layout and thermal requirements must be evaluated before implementation.

Q: Why does the SCHURTER part have a higher melting I²t value?

A: The melting I²t value (6.2 for SCHURTER vs. 3.4 for MQ 5) indicates different thermal response characteristics. This difference reflects the physical construction and material composition of the fuse element. Both parts maintain the same 5A current rating and fast-blow response classification, but thermal behavior during fault conditions differs.

Q: Are all substitute parts RoHS compliant?

A: The Littelfuse parts (0251005.MXL and 0251005.NRT1L) are ROHS3 Compliant. The SCHURTER 7010.7130.13 is also ROHS3 Compliant. The original MQ 5 does not specify RoHS status.

Q: What regulatory approvals should I consider for my application?

A: The Littelfuse alternatives carry broader regulatory approvals (CCC, CSA, cURus, PSE, TUV) compared to the original MQ 5 (CE, CSA, cURus). The SCHURTER part carries CSA and UR approvals. Select the substitute based on your specific regulatory requirements for your target market and application.

Q: Can I use these parts in high-temperature applications?

A: The Littelfuse parts support operating temperatures up to 125°C, matching the original MQ 5. The SCHURTER part is limited to 85°C maximum operating temperature. For applications requiring operation above 85°C, use the Littelfuse alternatives.