Littelfuse 06643.15HXLL Equivalent & Substitute Parts

Part Overview

The Littelfuse 06643.15HXLL is a 3.15 A, 250 V AC/DC board mount fuse with slow blow response characteristics, designed for through-hole radial mounting in vertical orientation. This component is classified as obsolete, making identification of active equivalent parts essential for ongoing design support and procurement continuity. The substitute part 38213150000 from the TR5® 382 series provides functional equivalence while maintaining active product status.

Substiute Parts

06643.15HXLL

Littelfuse Inc.In Stock: 87606643.15HXLL Datasheet

Current PartRFQ

38213150000

Littelfuse Inc.In Stock: 5905338213150000 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution between the 06643.15HXLL (LT-5™ 664 series) and 38213150000 (TR5® 382 series) is valid based on the following matched electrical and mechanical parameters:

• Current Rating: Both rated at 3.15 A
• Voltage Rating: Both rated at 250 V AC
• Response Characteristic: Both classified as Slow Blow
• Mounting Configuration: Both Through Hole, Radial, Can, Vertical orientation
• Breaking Capacity: Both rated at 100 A @ rated voltage
• Operating Temperature: Both operate across -40°C to 85°C
• Regulatory Compliance: Both ROHS3 Compliant
• Fuse Type: Both Board Mount (Cartridge Style Excluded)

The primary distinction is product status: the 06643.15HXLL is obsolete, while 38213150000 is active with significantly higher inventory availability (59,030 pcs vs. 811 pcs).

Parameter Comparison

Engineering Selection Recommendations

The 38213150000 (TR5® 382 series) is the direct active equivalent for the obsolete 06643.15HXLL (LT-5™ 664 series). Both components share identical electrical ratings (3.15 A, 250 V AC, Slow Blow response) and mechanical mounting specifications (Through Hole, Radial, Can, Vertical). The substitute maintains all critical safety certifications and regulatory compliance (ROHS3, EAR99 classification).

Physical dimensions differ slightly: the TR5® 382 is 0.315" H (8.00mm) versus the LT-5™ 664 at 0.333" H (8.45mm). This 0.018" (0.45mm) height reduction is within typical PCB layout tolerances for radial through-hole components and does not affect electrical performance or thermal characteristics.

The melting I²t value of the substitute (45.35) is lower than the original (57), indicating slightly faster thermal response. The DC cold resistance is marginally lower (0.0176 Ohms vs. 0.02 Ohms), representing a negligible difference in circuit performance.

Selection of 38213150000 is supported by active product status, higher inventory availability, and maintained compliance with all applicable regulatory frameworks.

Frequently Asked Questions (FAQ)

Q: Can the 38213150000 be used as a direct replacement for the 06643.15HXLL in existing designs?

A: Yes. Both components share identical current rating (3.15 A), voltage rating (250 V AC), response characteristic (Slow Blow), and mounting configuration (Through Hole, Radial, Vertical). The slight height difference (0.018") does not affect PCB layout compatibility for standard radial through-hole footprints.

Q: What is the significance of the different melting I²t values?

A: The melting I²t parameter defines the thermal energy required to melt the fuse element. The 38213150000 has a lower I²t (45.35 vs. 57), indicating slightly faster thermal response under fault conditions. Both values remain within the slow blow classification and maintain the 100 A breaking capacity at rated voltage.

Q: Are there any certification differences between these parts?

A: Both components are ROHS3 Compliant and carry EAR99 classification. The 06643.15HXLL lists approvals: CCC, CSA, KTL, METI, SEMKO, UL, VDE. The 38213150000 lists: CCC, cURus, KC, PSE/JET, SEMKO, VDE. Both maintain equivalent safety and regulatory standing for board mount fuse applications.

Q: Why is the 06643.15HXLL classified as obsolete?

A: Littelfuse has transitioned the LT-5™ 664 series to obsolete status in favor of the active TR5® 382 series. The TR5® 382 provides equivalent electrical and mechanical performance with improved manufacturing continuity and supply chain availability.

Q: What is the packaging difference between these parts?

A: The 06643.15HXLL is supplied in standard packaging (not specified), while the 38213150000 is supplied in Cut Tape (CT) format. Cut Tape packaging is standard for automated assembly processes and does not affect component functionality.

Q: Can these parts be used interchangeably in new designs?

A: Yes. For new designs, the 38213150000 is the recommended selection due to active product status and superior supply chain availability. The electrical and mechanical specifications are equivalent, and all regulatory compliance requirements are maintained.