Littelfuse 0437.750WR Surface Mount Fuse - Equivalent & Substitute Parts

Part Overview

The Littelfuse 0437.750WR is a 750 mA, 63 V AC/DC surface mount fuse in 1206 (3216 Metric) package format with fast blow response characteristics. This component is designed for board-level circuit protection in applications requiring reliable overcurrent interruption at low voltage levels. The part maintains active product status with full RoHS3 compliance and CSA/UL approval certifications. Substitute parts are identified when equivalent electrical performance and mechanical compatibility are required due to inventory constraints, packaging format preferences, or supply chain considerations.

Substiute Parts

0437.750WR

Littelfuse Inc.In Stock: 4840820437.750WR Datasheet

Current PartRFQ

0440.750WR

Littelfuse Inc.In Stock: 183790440.750WR Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 0437.750WR is determined by strict equivalence across the following critical parameters:

• Current Rating: 750 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)
• Breaking Capacity: 50 A @ Rated Voltage (exact match required)
• Operating Temperature: -55°C to 150°C (exact match required)

The substitute part 0440.750WR meets all electrical and mechanical equivalence criteria. The primary difference between the main part and substitute is the packaging format (Cut Tape & Digi-Reel® versus Tape & Reel) and minor variations in DC cold resistance and melting I²t values, which do not affect functional interchangeability in circuit protection applications.

Parameter Comparison

Engineering Selection Recommendations

Both the 0437.750WR and 0440.750WR are active products from Littelfuse Inc. with full RoHS3 compliance and regulatory approvals (CSA and UL certifications). Selection between these parts should be based on packaging and supply requirements:

• The 0437.750WR in Cut Tape & Digi-Reel® format is suitable for lower-volume applications and manual assembly processes.
• The 0440.750WR in Tape & Reel format is optimized for high-volume automated assembly operations.

Both parts provide equivalent circuit protection performance with identical electrical ratings, response characteristics, and thermal operating ranges. The minor differences in DC cold resistance and melting I²t do not affect functional interchangeability for standard board-level overcurrent protection applications.

Frequently Asked Questions (FAQ)

Q: Can the 0440.750WR replace the 0437.750WR in existing designs?

A: Yes. Both parts are electrically and mechanically equivalent with identical current ratings (750 mA), voltage ratings (63 V AC/DC), response time (Fast Blow), package format (1206 / 3216 Metric), and operating temperature range (-55°C to 150°C). The primary difference is packaging format (Cut Tape & Digi-Reel® versus Tape & Reel).

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

A: The DC cold resistance values (0.665 Ohms for 0437.750WR and 0.4624 Ohms for 0440.750WR) reflect minor manufacturing variations within the same product family. Both values are within acceptable tolerances for fuse element performance and do not affect circuit protection functionality.

Q: Are there any approval or compliance differences between these parts?

A: Both parts are RoHS3 compliant and carry CSA approval. The 0437.750WR carries UR approval while the 0440.750WR carries UL approval. Both certifications are recognized regulatory standards for circuit protection components.

Q: Which packaging format should be selected for new designs?

A: Packaging selection depends on manufacturing requirements. Cut Tape & Digi-Reel® format (0437.750WR) is suitable for manual or semi-automated assembly. Tape & Reel format (0440.750WR) is optimized for fully automated pick-and-place assembly operations.

Q: Are these parts interchangeable at the PCB footprint level?

A: Yes. Both parts use identical 1206 (3216 Metric) surface mount package dimensions (0.126" L x 0.064" W x 0.032" H), ensuring direct footprint compatibility on printed circuit boards.