ATQ25 Equivalent & Substitute Parts Reference

Part Overview

The ATQ25 is a 500V 25A TD Midget fuse manufactured by Mersen USA Newburyport-MA L.L.C. This uncategorized fuse is designed for circuit protection applications requiring a 25-ampere current rating at 500 volts. The part maintains Active product status with ROHS3 compliance. Equivalent and substitute parts become necessary when addressing supply chain constraints, regional availability differences, or specific application requirements that may benefit from alternative manufacturer specifications while maintaining electrical and mechanical compatibility.

Substiute Parts

ATQ25

Mersen USA Newburyport-MA L.L.C.In Stock: 943ATQ25 Datasheet

Current PartRFQ

0FLQ025.T

Littelfuse Inc.In Stock: 10180FLQ025.T Datasheet

SimilarRFQ

FNQ-25

Eaton - Bussmann Electrical DivisionIn Stock: 756FNQ-25 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the ATQ25 is determined by the following critical parameters:

• Current Rating: 25A (exact match required)
• Voltage Rating - AC: 500V (exact match required)
• Package / Case: 5AG, 10mm x 38mm (Midget) (exact match required)
• Fuse Type: Cartridge with slow-blow response characteristics
• Mounting Type: Requires Holder (mechanical compatibility)
• Product Status: Active (current availability)
• RoHS Compliance: ROHS3 Compliant (regulatory alignment)

The identified substitute parts meet all critical electrical parameters (25A at 500VAC) and mechanical specifications (5AG Midget form factor). Both substitutes are cartridge fuses requiring a holder, maintain Active product status, and comply with ROHS3 requirements, ensuring direct functional equivalence within the specified application envelope.

Parameter Comparison

Engineering Selection Recommendations

All three parts maintain Active product status and ROHS3 compliance, establishing baseline regulatory and supply chain viability. The 0FLQ025.T (Littelfuse POWR-GARD® FLQ series) provides dual voltage capability with 300VDC rating in addition to 500VAC, offering expanded application flexibility for circuits requiring DC protection. The FNQ-25 (Eaton Bussmann FNQ series) includes CE certification alongside CSA and UL approvals, providing broader international regulatory coverage. Selection between substitutes should be based on specific application voltage requirements (AC-only versus AC/DC capability) and regional certification requirements. All parts share identical current ratings, voltage ratings for AC operation, mechanical form factors, and response characteristics, ensuring direct functional substitution within 500VAC 25A circuit protection applications.

Frequently Asked Questions (FAQ)

Q: Can the 0FLQ025.T replace the ATQ25 in all applications? A: The 0FLQ025.T meets all critical electrical parameters (25A, 500VAC) and mechanical specifications (5AG Midget form factor). The additional 300VDC rating does not restrict AC-only applications. Substitution is valid for 500VAC 25A circuit protection requirements.

Q: What is the significance of the slow-blow (TD) response characteristic? A: Slow-blow fuses tolerate temporary inrush currents without nuisance operation, making them suitable for transformer protection and inductive load applications. All listed substitutes maintain this slow-blow response characteristic, preserving application compatibility.

Q: Are there mechanical compatibility concerns when switching between manufacturers? A: All three parts conform to the 5AG Midget form factor (10mm x 38mm) and require a standard fuse holder. Dimensional tolerances (0.406" diameter x 1.500" length) are equivalent across all parts, ensuring mechanical interchangeability within existing holder assemblies.

Q: How do certification differences affect substitution decisions? A: The ATQ25 certification status is not specified in available data. The 0FLQ025.T carries CSA and UL approvals; the FNQ-25 carries CE, CSA, and UL approvals. Selection should align with regional regulatory requirements and end-application certification standards.

Q: Is the FNQ-25 suitable for applications requiring DC voltage protection? A: The FNQ-25 specification lists only 500VAC rating with no DC voltage specification. For applications requiring DC protection, the 0FLQ025.T with its 300VDC rating is the appropriate choice among the listed substitutes.

Q: What inventory considerations apply to these substitutes? A: Current stock levels are 920 pcs (ATQ25), 963 pcs (0FLQ025.T), and 682 pcs (FNQ-25). All parts maintain New Original status, indicating equivalent supply chain reliability and product condition.