Littelfuse 0273.400H Board Mount Fuse - Equivalent & Substitute Parts

Part Overview

The Littelfuse 0273.400H is a 400 mA, 125 V AC/DC board mount fuse in the MICRO™ 273 series. This fast-blow fuse is designed for through-hole radial mounting in compact applications requiring reliable overcurrent protection. The part is active in production with full inventory availability and carries multiple international approvals including CSA, QPL, and UL certification. Substitute parts are identified when identical electrical and mechanical specifications are required for design flexibility, supply chain continuity, or inventory management.

Substiute Parts

0273.400H

Littelfuse Inc.In Stock: 9400273.400H Datasheet

Current PartRFQ

0273.400V

Littelfuse Inc.In Stock: 10030273.400V Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

The Littelfuse 0273.400V is identified as a parametric equivalent to the 0273.400H based on identical electrical and mechanical specifications. Substitution is valid when the following key parameters match exactly:

• Current Rating: 400 mA
• Voltage Rating (AC/DC): 125 V / 125 V
• Response Time: Fast Blow
• Mounting Type: Through Hole
• Package / Case: Radial, Can, Vertical
• Breaking Capacity: 10 kA
• Operating Temperature Range: -55°C to 85°C
• Physical Dimensions: 0.250" Dia x 0.350" H
• DC Cold Resistance: 0.227 Ohms
• Melting I²t: 0.0251
• Approval Agencies: CSA, QPL, UL
• RoHS Compliance: ROHS3 Compliant

Both parts belong to the MICRO™ 273 series and maintain identical thermal and electrical performance characteristics. The substitute relationship is bidirectional.

Parameter Comparison

Engineering Selection Recommendations

Both the 0273.400H and 0273.400V are active production parts from Littelfuse with full regulatory compliance. Selection between these parts should be based on availability and supply chain requirements rather than technical performance, as all electrical, mechanical, and thermal specifications are identical. Both parts carry CSA, QPL, and UL approvals, confirming suitability for regulated applications. ROHS3 compliance and unlimited moisture sensitivity rating (MSL 1) ensure compatibility with standard manufacturing and storage environments. The 10 kA breaking capacity and 0.0251 melting I²t rating provide consistent overcurrent protection performance across both part numbers.

Frequently Asked Questions (FAQ)

Q: Can 0273.400V be used as a direct replacement for 0273.400H in existing designs?

A: Yes. Both parts are electrically and mechanically identical with matching current ratings (400 mA), voltage ratings (125 V AC/DC), response time (fast blow), physical dimensions (0.250" Dia x 0.350" H), and all thermal characteristics. No design modifications are required.

Q: Are there any differences in approval certifications between these parts?

A: No. Both parts carry identical approvals from CSA, QPL, and UL, confirming equivalent regulatory compliance for all applications.

Q: Do these parts have the same mounting footprint?

A: Yes. Both parts use through-hole radial mounting with identical physical dimensions of 0.250" diameter by 0.350" height (6.35 mm x 8.89 mm). PCB layout and mounting hole spacing are identical.

Q: What is the difference between the 0273.400H and 0273.400V part numbers?

A: The part numbers differ only in their suffix designation (H versus V). All electrical, mechanical, thermal, and compliance specifications are identical. The difference reflects internal Littelfuse manufacturing or distribution tracking and does not affect functional performance.

Q: Are both parts suitable for the same operating temperature range?

A: Yes. Both parts operate across the identical temperature range of -55°C to 85°C with no performance variation.

Q: Can these parts be intermixed in production inventory?

A: Yes. Since all specifications are identical, these parts can be used interchangeably in manufacturing and assembly operations without affecting product performance or compliance.