Littelfuse 0274.600V Board Mount Fuse - Equivalent & Substitute Parts

Part Overview

The Littelfuse 0274.600V is a 500 mA, 125 V AC/DC board mount fuse designed for through-hole radial mounting in the MICRO™ 273 series. This fast-blow fuse is actively manufactured and widely used in industrial and commercial electronic equipment requiring overcurrent protection. Finding equivalent substitute parts is necessary to ensure supply chain continuity, optimize inventory management, and maintain design flexibility across manufacturing batches and procurement cycles.

Substiute Parts

0273.500V

Littelfuse Inc.In Stock: 8180273.500V Datasheet

Current PartRFQ

0279.500V

Littelfuse Inc.In Stock: 9030279.500V Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

The Littelfuse 0279.500V qualifies as a parametric equivalent to the 0274.600V based on identical electrical and mechanical specifications. Substitution is valid when the following criteria are met:

• Current Rating: 500 mA (exact match)
• Voltage Rating - AC: 125 V (exact match)
• Voltage Rating - DC: 125 V (exact match)
• Response Time: Fast Blow (exact match)
• Mounting Type: Through Hole (exact match)
• Package / Case: Radial, Can, Vertical (exact match)
• Breaking Capacity @ Rated Voltage: 10 kA (exact match)
• Operating Temperature Range: -55°C to 85°C (exact match)
• Physical Dimensions: 0.250" Dia x 0.350" H (exact match)
• DC Cold Resistance: 0.167 Ohms (exact match)
• Melting I²t: 0.0716 (exact match)
• Regulatory Compliance: CSA, QPL, UL (exact match)

The primary difference between these parts 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 0274.600V and 0279.500V are actively manufactured by Littelfuse Inc. and carry identical regulatory certifications (CSA, QPL, UL). Both parts maintain ROHS3 compliance and are unaffected by REACH regulations. Selection between these parts should be based on:

• Availability and lead time from your procurement source
• Inventory stock levels (0274.600V: 713 pcs; 0279.500V: 840 pcs)
• Internal design documentation and bill of materials requirements
• Supplier preference and pricing

No technical performance difference exists between these parts when used in applications requiring 500 mA, 125 V AC/DC board mount fuses with fast-blow response characteristics.

Frequently Asked Questions (FAQ)

Q: Can the 0279.500V be used as a direct replacement for the 0274.600V in existing designs?

A: Yes. Both parts are electrically and mechanically identical across all specified parameters, including current rating, voltage rating, response time, physical dimensions, and regulatory approvals. No circuit redesign or PCB modification is required.

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

A: The series designation reflects Littelfuse's internal product line evolution. From an engineering standpoint, both series share identical electrical characteristics and mechanical specifications for this 500 mA, 125 V rating. The difference is internal to the manufacturer's design and does not affect functional performance.

Q: Are the physical dimensions identical?

A: Yes. Both parts measure 0.250" diameter by 0.350" height (6.35 mm x 8.89 mm) and use the same radial, can, vertical mounting configuration. They are pin-compatible and footprint-compatible on PCBs designed for either part number.

Q: Do both parts have the same breaking capacity?

A: Yes. Both the 0274.600V and 0279.500V have a breaking capacity of 10 kA at rated voltage, ensuring equivalent protection performance in overcurrent conditions.

Q: What is the melting I²t value, and is it the same for both parts?

A: The melting I²t value is 0.0716 for both parts. This parameter defines the thermal energy required to melt the fuse element and is critical for coordinating fuse protection with upstream circuit protection devices. Identical values confirm equivalent protection characteristics.

Q: Are both parts RoHS compliant?

A: Yes. Both the 0274.600V and 0279.500V are ROHS3 compliant and unaffected by REACH regulations, meeting environmental and regulatory requirements for commercial and industrial applications.

Q: What is the DC cold resistance specification?

A: Both parts have a DC cold resistance of 0.167 Ohms. This low resistance minimizes voltage drop across the fuse during normal operation and is identical between the two part numbers.

Q: Can these fuses be used in both AC and DC circuits?

A: Yes. Both parts are rated for 125 V AC and 125 V DC operation, making them suitable for use in AC mains circuits, DC power supplies, and mixed-signal applications within the specified voltage range.