Littelfuse 0279.050V Equivalent & Substitute Parts

Part Overview

The Littelfuse 0279.050V is a 50 mA, 125 V AC/DC board mount fuse in the MICRO™ 279 series, designed for through-hole radial mounting applications. This fast-blow fuse provides circuit protection in compact form factor with a breaking capacity of 10 kA at rated voltage. The part is active in production and widely available, with 940 units in current inventory. Alternative models may be required due to supply constraints, design revisions, or specific application requirements where equivalent electrical and mechanical characteristics are maintained.

Substiute Parts

0279.050V

LittelfuseIn Stock: 10480279.050V Datasheet

Current PartRFQ

0273.050H

Littelfuse Inc.In Stock: 14920273.050H Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

The Littelfuse 0273.050H qualifies as a parametric equivalent to the 0279.050V based on the following critical substitution criteria:

Electrical Parameters (Identical):

• Current Rating: 50 mA
• Voltage Rating AC: 125 V
• Voltage Rating DC: 125 V
• Response Time: Fast Blow
• Breaking Capacity @ Rated Voltage: 10 kA
• Melting I²t: 6.66E-05
• DC Cold Resistance: 3.2 Ohms

Mechanical Parameters (Identical):

• Mounting Type: Through Hole
• Fuse Type: Board Mount (Cartridge Style Excluded)
• Package / Case: Radial, Can, Vertical
• Size / Dimension: 0.250" Dia x 0.350" H (6.35 mm x 8.89 mm)

Environmental & Compliance (Identical):

• Operating Temperature Range: -55°C to 85°C
• Approval Agencies: CSA, QPL, UL
• RoHS Status: ROHS3 Compliant
• REACH Status: REACH Unaffected

The primary difference is the series designation (MICRO™ 273 versus MICRO™ 279), which reflects internal design evolution within Littelfuse's product line while maintaining full electrical and mechanical compatibility.

Parameter Comparison

Engineering Selection Recommendations

Both the Littelfuse 0279.050V and 0273.050H are active production parts with identical electrical, mechanical, and environmental specifications. Selection between these parts should be based on the following factors:

Availability: The 0273.050H offers higher inventory availability (1400 units) compared to the 0279.050V (940 units), making it suitable for high-volume applications or when supply continuity is critical.

Compliance & Certification: Both parts carry identical approvals (CSA, QPL, UL) and maintain ROHS3 compliance and REACH unaffected status, ensuring regulatory compatibility in all applications where the main part is specified.

Series Continuity: The 0279.050V maintains the MICRO™ 279 series designation. The 0273.050H represents the MICRO™ 273 series. Where design documentation explicitly specifies series designation, the corresponding part number should be used. Where only electrical and mechanical specifications are referenced, either part is functionally equivalent.

Direct Substitution: The 0273.050H is a direct parametric substitute for the 0279.050V in all circuit protection applications requiring 50 mA fast-blow protection at 125 V AC/DC with through-hole radial mounting.

Frequently Asked Questions (FAQ)

Q: Can the 0273.050H be used as a direct replacement for the 0279.050V in existing designs?

A: Yes. The 0273.050H is a parametric equivalent with identical current rating, voltage rating, response time, breaking capacity, physical dimensions, and thermal operating range. No circuit modifications are required.

Q: Are there any differences in performance between the 0279.050V and 0273.050H?

A: No. Both parts have identical electrical characteristics including melting I²t (6.66E-05), DC cold resistance (3.2 Ohms), and breaking capacity (10 kA at rated voltage). Performance in circuit protection applications is equivalent.

Q: Do both parts have the same certifications?

A: Yes. Both the 0279.050V and 0273.050H carry CSA, QPL, and UL approvals. Both are ROHS3 compliant and REACH unaffected, meeting identical regulatory requirements.

Q: What is the difference between the MICRO™ 279 and MICRO™ 273 series?

A: The series designation reflects internal product line organization within Littelfuse. From an engineering standpoint, the 0273.050H and 0279.050V are functionally identical in all electrical, mechanical, and environmental parameters.

Q: Will the 0273.050H fit in the same PCB footprint as the 0279.050V?

A: Yes. Both parts have identical physical dimensions (0.250" Dia x 0.350" H / 6.35 mm x 8.89 mm) and identical through-hole radial mounting configuration. PCB footprints are interchangeable.

Q: Which part should I specify for new designs?

A: Either part is acceptable for new designs. Selection may be based on current inventory availability or existing supply chain relationships with Littelfuse. Both parts are active in production with equivalent long-term availability.

Q: Are there any temperature or environmental limitations that differ between these parts?

A: No. Both parts operate across the identical temperature range of -55°C to 85°C and have identical moisture sensitivity level (MSL 1 - Unlimited).