Littelfuse 0429.500WRM Surface Mount Fuse - Equivalent & Substitute Parts

Part Overview

The Littelfuse 0429.500WRM is a 500 mA, 63 V AC/DC surface mount board fuse in 1206 (3216 Metric) package with fast blow response characteristics. This part is classified as obsolete, making identification of suitable substitute components necessary for ongoing design support and procurement planning. The part features CSA and UL approval agencies and operates across a temperature range of -55°C to 90°C.

Substiute Parts

0429.500WRM

Littelfuse Inc.In Stock: 170890429.500WRM Datasheet

Current PartRFQ

0466.500NR

Littelfuse Inc.In Stock: 154400466.500NR Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 0429.500WRM is determined by strict equivalence across the following critical parameters:

• Current Rating: 500 mA (exact match required)
• Voltage Rating: 63 V AC and 63 V DC (exact match required)
• Response Time: Fast Blow (exact match required)
• Package / Case: 1206 (3216 Metric) (exact match required)
• Mounting Type: Surface Mount (exact match required)
• Fuse Type: Board Mount (Cartridge Style Excluded) (exact match required)

The Littelfuse 0466.500NR meets all substitution criteria. This part belongs to the SlimLine™ 466 series and maintains electrical equivalence while offering improved product status and compliance characteristics.

Parameter Comparison

Engineering Selection Recommendations

The Littelfuse 0466.500NR is the direct substitute for the obsolete 0429.500WRM. Both parts maintain identical electrical specifications across current rating, voltage ratings, response time, and thermal operating range. The 0466.500NR offers the following advantages:

• Active product status ensures continued availability and manufacturing support
• ROHS3 compliance meets current environmental regulatory requirements
• Reduced profile height (0.023" vs 0.045") provides improved board layout flexibility
• Specified breaking capacity of 50A at rated voltage provides additional performance documentation
• Maintained CSA and UL approvals preserve certification continuity

The DC cold resistance differential (0.248 Ohms vs 0.2405 Ohms) remains within acceptable tolerance for this component class and does not affect functional equivalence.

Frequently Asked Questions (FAQ)

Q: Can the 0466.500NR be used as a direct replacement for the 0429.500WRM in existing designs?

A: Yes. Both parts share identical electrical ratings (500 mA, 63 V AC/DC, fast blow response), package type (1206 / 3216 Metric), and mounting configuration (surface mount). The 0466.500NR is electrically and mechanically equivalent.

Q: What is the significance of the height difference between these parts?

A: The 0466.500NR has a reduced profile height of 0.023" compared to 0.045" for the 0429.500WRM. This lower profile may provide advantages in space-constrained board layouts. Verify PCB footprint and component clearance requirements for your specific application.

Q: Does the RoHS3 compliance of the 0466.500NR affect compatibility?

A: No. RoHS3 compliance is an environmental and regulatory advantage. The 0429.500WRM is RoHS non-compliant, while the 0466.500NR meets current RoHS3 standards. This makes the substitute part suitable for applications with environmental compliance requirements.

Q: Are the approval agencies the same for both parts?

A: Yes. Both the 0429.500WRM and 0466.500NR carry CSA and UL approvals, maintaining certification continuity for regulated applications.

Q: What does the breaking capacity specification mean?

A: Breaking capacity (50A for the 0466.500NR) indicates the maximum current the fuse can safely interrupt at its rated voltage. The main part does not specify this value. This additional specification for the substitute part provides enhanced performance documentation.

Q: Is the DC cold resistance difference significant?

A: The DC cold resistance values (0.2405 Ohms vs 0.248 Ohms) represent a negligible difference of approximately 3% and remain within acceptable tolerance for this component class. This does not affect functional equivalence or circuit performance.