Equivalent & Substitute Parts for Littelfuse 06641.25HXLL

Part Overview

The Littelfuse 06641.25HXLL is a 1.25 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 The LT-5™ 664 series fuse has been superseded by newer product lines that maintain electrical and mechanical compatibility while offering improved availability and active manufacturing status.

Substiute Parts

06641.25HXLL

Littelfuse Inc.In Stock: 111706641.25HXLL Datasheet

Current PartRFQ

38211250000

LittelfuseIn Stock: 2011638211250000 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 06641.25HXLL is determined by strict equivalence across the following electrical and mechanical parameters:

• Current Rating: 1.25 A (exact match required)
• Voltage Rating: 250 V AC (exact match required)
• Response Time: Slow Blow (exact match required)
• Mounting Type: Through Hole (exact match required)
• Package / Case: Radial, Can, Vertical (exact match required)
• Breaking Capacity: 100 A (exact match required)
• Operating Temperature Range: -40°C to 85°C (exact match required)

The substitute part 38211250000 (Littelfuse TR5® 382 series) meets all these criteria. While minor variations exist in physical dimensions and DC cold resistance, these differences remain within acceptable tolerances for board-level integration and do not affect functional performance in the specified application envelope.

Parameter Comparison

Engineering Selection Recommendations

The 38211250000 is the direct active equivalent for the obsolete 06641.25HXLL. Selection of this substitute is based on:

• Identical electrical ratings across current, voltage, and response characteristics
• Matching mechanical form factor and mounting interface
• Active product status with established supply chain availability
• Full regulatory compliance including CCC, cURus, KC, PSE/JET, SEMKO, and VDE certifications
• ROHS3 compliance maintained across both parts
• Equivalent breaking capacity and operating temperature envelope

The substitute part carries enhanced certifications (cURus, KC, PSE/JET) compared to the original part, providing expanded market acceptance. Physical height variation (0.333" vs 0.315") is negligible for through-hole radial mounting applications and does not impact PCB layout or component clearance.

Frequently Asked Questions (FAQ)

Q: Can 38211250000 be used as a direct replacement for 06641.25HXLL without PCB modification?

A: Yes. Both parts share identical electrical specifications, mounting type, and radial can vertical package configuration. The 0.018" height difference does not require PCB redesign for standard through-hole applications.

Q: What is the primary reason for substitution?

A: The 06641.25HXLL is obsolete. The 38211250000 is an active product from the same manufacturer with identical functional characteristics, ensuring long-term availability and supply continuity.

Q: Are there differences in thermal or electrical performance?

A: DC cold resistance differs (0.085 Ohms vs 0.05 Ohms) and melting I²t varies slightly (6.3 vs 6.88). These variations remain within the slow blow fuse performance envelope and do not affect circuit protection function at the specified 1.25 A rating.

Q: What certifications apply to the substitute part?

A: The 38211250000 carries CCC, cURus, KC, PSE/JET, SEMKO, and VDE approvals. The original part carried CCC, CSA, KTL, METI, SEMKO, UL, and VDE approvals. Both meet regional regulatory requirements for board mount fuses.

Q: Is packaging different between the two parts?

A: The main part is listed with standard packaging, while the substitute is supplied in Cut Tape (CT) format. This affects procurement and handling but does not impact component performance or compatibility.