Littelfuse 066506.3ZRLL Board Mount Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 066506.3ZRLL is a 6.3 A, 250 V AC/DC board mount fuse with slow blow response characteristics, designed for through-hole radial mounting in radial can vertical package configuration. This part operates within the temperature range of -40°C to 85°C and meets CSA and UL approval standards. The product is currently obsolete, making identification of equivalent substitute parts essential for ongoing system maintenance and new design implementations where this specification is required.

Substiute Parts

066506.3ZRLL

Littelfuse Inc.In Stock: 950066506.3ZRLL Datasheet

Current PartRFQ

37416300000

Littelfuse Inc.In Stock: 721437416300000 Datasheet

DirectRFQ

0034.7123

SCHURTER Inc.In Stock: 20520034.7123 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 066506.3ZRLL are qualified based on strict electrical and mechanical parameter alignment:

Primary Substitution Criteria:

• Current Rating: 6.3 A (exact match required)
• Voltage Rating (AC): 250 V (exact match required)
• Response Time: Slow Blow (exact match required)
• Mounting Type: Through Hole (exact match required)
• Fuse Type: Board Mount, Cartridge Style Excluded (exact match required)
• Package / Case: Radial, Can, Vertical (exact match required)
• Breaking Capacity @ Rated Voltage: 50 A (exact match required)
• Operating Temperature Range: -40°C to 85°C (exact match required)
• RoHS Compliance: ROHS3 Compliant (exact match required)

Two substitute parts meet these criteria: Littelfuse 37416300000 (TR5® 374 series, active status) and SCHURTER 0034.7123 (MSTU 250 series, active status). Both maintain identical electrical specifications and mechanical form factors suitable for direct board-level substitution.

Parameter Comparison

Engineering Selection Recommendations

Littelfuse 37416300000 (TR5® 374 Series)

This substitute is an active product from the original manufacturer, Littelfuse Inc., ensuring ongoing availability and technical support. It carries CSA and cULus approvals, meeting regulatory requirements for the application. The TR5® 374 series maintains all critical electrical parameters identical to the obsolete 066506.3ZRLL. Physical dimensions show a height variation of 0.018" (0.45mm), which remains within typical PCB layout tolerances for radial through-hole components. This option provides direct manufacturer continuity and is recommended for new designs and production restocking.

SCHURTER 0034.7123 (MSTU 250 Series)

This substitute is an active product from SCHURTER Inc., an established fuse manufacturer with cULus certification. The MSTU 250 series maintains all critical electrical specifications and mechanical compatibility with the obsolete part. Physical dimensions match the original part precisely at 0.335" diameter and 0.335" height. This option provides cross-manufacturer compatibility and is suitable for applications requiring alternative sourcing or supply chain diversification.

Frequently Asked Questions (FAQ)

Q: Can the Littelfuse 37416300000 be used as a direct replacement for the 066506.3ZRLL?

A: Yes. Both parts share identical current rating (6.3 A), voltage rating (250 V AC), response time (Slow Blow), mounting type (Through Hole), fuse type (Board Mount), package configuration (Radial, Can, Vertical), breaking capacity (50 A), and operating temperature range (-40°C to 85°C). The height dimension differs by 0.018" (0.45mm), which is within standard PCB layout tolerances for radial through-hole components.

Q: Can the SCHURTER 0034.7123 be used as a direct replacement for the 066506.3ZRLL?

A: Yes. Both parts share identical current rating (6.3 A), voltage rating (250 V AC), response time (Slow Blow), mounting type (Through Hole), fuse type (Board Mount), package configuration (Radial, Can, Vertical), breaking capacity (50 A), and operating temperature range (-40°C to 85°C). Physical dimensions are identical at 0.335" diameter and 0.335" height.

Q: What is the difference between the two substitute parts?

A: Both substitutes meet all electrical and mechanical requirements. The primary differences are manufacturer (Littelfuse vs. SCHURTER), series designation (TR5® 374 vs. MSTU 250), packaging format (Cut Tape vs. Bulk), and minor physical height variations. Selection depends on supply chain preferences, inventory availability, and sourcing strategy.

Q: Are there any compliance or certification differences between the substitutes?

A: The Littelfuse 37416300000 carries CSA and cULus approvals. The SCHURTER 0034.7123 carries cULus approval. Both meet ROHS3 compliance requirements. Verify that the selected substitute's certification portfolio aligns with your specific application and regional regulatory requirements.

Q: What is the significance of the melting I²t values shown in the specifications?

A: Melting I²t is a thermal characteristic that describes the fuse's energy absorption capacity. The 066506.3ZRLL and SCHURTER 0034.7123 both specify 287 melting I²t, while the Littelfuse 37416300000 specifies 110 melting I²t. This difference reflects different thermal response characteristics within the same slow-blow classification and should be evaluated against your circuit's specific inrush current and thermal protection requirements.

Q: Can these parts be used interchangeably in existing PCB designs?

A: The Littelfuse 37416300000 and SCHURTER 0034.7123 are mechanically compatible with existing through-hole radial mounting patterns designed for the 066506.3ZRLL. Minor height variations (0.018" for Littelfuse, 0.002" for SCHURTER) are within standard PCB layout tolerances. Verify component placement clearances in your specific PCB design before implementation.