Littelfuse 0441004.WR Surface Mount Fuse 4A 32VDC 0603 Equivalent & Substitute Parts

Part Overview

The Littelfuse 0441004.WR is a surface mount board fuse rated for 4A at 32VDC with fast-blow response characteristics. This component is designed for circuit protection in compact 0603 (1608 Metric) form factor applications. The part maintains active product status with full RoHS3 compliance and CSA/UL approval certifications. Substitute parts are identified to provide alternative sourcing options when primary inventory is unavailable or when specific certification requirements differ across application requirements.

Substiute Parts

0441004.WR

Littelfuse Inc.In Stock: 538140441004.WR Datasheet

Current PartRFQ

0438004.WRGT

Littelfuse Inc.In Stock: 183360438004.WRGT Datasheet

Parametric EquivalentRFQ

0441004.WRA

Littelfuse Inc.In Stock: 70510441004.WRA Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 0441004.WR are qualified based on the following critical parameters that determine functional interchangeability:

Primary Substitution Criteria:

• Current Rating: 4 A (exact match required)
• Voltage Rating - DC: 32 V (exact match required)
• Package / Case: 0603 (1608 Metric) (exact match required)
• Mounting Type: Surface Mount (exact match required)
• Response Time: Fast Blow (exact match required)
• Fuse Type: Board Mount (Cartridge Style Excluded) (exact match required)

Secondary Compatibility Factors:

• Operating Temperature Range: -55°C ~ 150°C (must meet or exceed)
• Breaking Capacity @ Rated Voltage: 50A (must meet or exceed)
• Moisture Sensitivity Level: 1 (Unlimited) (must match or be superior)
• RoHS3 Compliance (required for modern applications)

Two substitute parts meet these criteria with variations in voltage rating scope and certification bodies.

Parameter Comparison

Engineering Selection Recommendations

0441004.WR (Primary Part): Maintains CSA and UL certifications. Suitable for applications requiring North American regulatory compliance. Current inventory of 53,804 pieces supports high-volume production requirements.

0438004.WRGT (Substitute - Extended Voltage Rating): Qualified as a parametric equivalent with extended AC voltage rating (12VAC) in addition to 32VDC capability. Certifications include CSA and cURus. The lower melting I²t value (0.739 versus 1.2659) and higher DC cold resistance (0.0164 Ohms versus 0.0097 Ohms) indicate faster thermal response. Suitable for applications requiring dual AC/DC voltage protection. Inventory of 18,300 pieces available.

0441004.WRA (Substitute - Alternative Certification): Functionally identical to the main part with matching current rating, voltage rating, and thermal characteristics (melting I²t 1.2659, DC cold resistance 0.0097 Ohms). Certifications include CE and cURus, supporting European regulatory requirements. Inventory of 7,026 pieces available.

Selection between substitutes depends on regulatory certification requirements for the target market and whether AC voltage protection is required in the application circuit.

Frequently Asked Questions (FAQ)

Q: Can 0438004.WRGT be used as a direct replacement for 0441004.WR?

A: The 0438004.WRGT meets all critical electrical parameters for 32VDC operation. However, it has a lower melting I²t value (0.739 versus 1.2659), indicating faster thermal response. This difference may affect circuit protection timing in applications with specific thermal response requirements. Certification bodies differ (CSA/cURus versus CSA/UL), which may impact regulatory compliance depending on application market.

Q: What is the significance of the DC cold resistance difference between parts?

A: DC cold resistance values of 0.0097 Ohms (0441004.WR and 0441004.WRA) versus 0.0164 Ohms (0438004.WRGT) affect voltage drop across the fuse during normal operation. The higher resistance in 0438004.WRGT results in greater voltage drop, which may be relevant in low-voltage or high-current applications where power dissipation is a design consideration.

Q: Are all three parts available in the same packaging format?

A: Yes. All three parts are supplied in Tape & Reel (TR) packaging and use identical 0603 (1608 Metric) surface mount form factor with dimensions of 0.061" L x 0.033" W x 0.020" H (1.54mm x 0.85mm x 0.50mm).

Q: Which substitute should be selected for European market applications?

A: The 0441004.WRA includes CE certification and is suitable for European regulatory requirements. The 0438004.WRGT carries CSA and cURus certifications, which are primarily North American and international standards.

Q: Do all parts meet RoHS3 compliance requirements?

A: Yes. All three parts (0441004.WR, 0438004.WRGT, and 0441004.WRA) are ROHS3 compliant with Moisture Sensitivity Level 1 (Unlimited) and REACH Unaffected status.