Equivalent & Substitute Parts for 0664004.ZRLL

Part Overview

The Littelfuse 0664004.ZRLL is a 4A 250VAC board mount radial fuse with slow blow response characteristics, designed for through-hole PCB applications. This part operates within the LT-5™ 664 series and carries an obsolete product status. Due to its obsolescence, identifying functionally equivalent active alternatives is essential for ongoing design support, production continuity, and long-term component availability.

Key Parameters

Parameter	Value
Current Rating	4 A
Voltage Rating (AC)	250 V
Response Time	Slow Blow
Mounting Type	Through Hole
Fuse Type	Board Mount (Cartridge Style Excluded)
Package / Case	Radial, Can, Vertical
Breaking Capacity @ Rated Voltage	100A
Operating Temperature Range	-40°C ~ 85°C
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution eligibility for the 0664004.ZRLL is determined by strict equivalence across the following parameters:

Current Rating: 4 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: 100A (exact match required)
Operating Temperature Range: -40°C ~ 85°C (exact match required)
RoHS Compliance: ROHS3 Compliant (exact match required)

Two substitute parts meet these criteria and are qualified for direct replacement:

38214000000 (Littelfuse Inc., TR5® 382 series) – Active product status
0034.6921 (SCHURTER Inc., MXT 250 series) – Active product status

Parameter Comparison

Parameter	0664004.ZRLL (Main)	38214000000 (Littelfuse)	0034.6921 (SCHURTER)
Manufacturer	Littelfuse Inc.	Littelfuse Inc.	SCHURTER Inc.
Series	LT-5™ 664	TR5® 382	MXT 250
Product Status	Obsolete	Active	Active
Current Rating (Amps)	4 A	4 A	4 A
Voltage Rating (AC)	250 V	250 V	250 V
Response Time	Slow Blow	Slow Blow	Slow Blow
Mounting Type	Through Hole	Through Hole	Through Hole
Fuse Type	Board Mount (Cartridge Style Excluded)	Board Mount (Cartridge Style Excluded)	Board Mount (Cartridge Style Excluded)
Package / Case	Radial, Can, Vertical	Radial, Can, Vertical	Radial, Can, Vertical
Breaking Capacity @ Rated Voltage	100A	100A	100A
Operating Temperature Range	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
Size / Dimension	0.335" Dia x 0.333" H (8.50mm x 8.45mm)	0.335" Dia x 0.315" H (8.50mm x 8.00mm)	0.335" Dia x 0.335" H (8.50mm x 8.50mm)
DC Cold Resistance	0.017 Ohms	0.0138 Ohms	Not specified
Melting I²t	77	72	77
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Packaging	-	Cut Tape (CT)	Bulk

Engineering Selection Recommendations

Both substitute parts are qualified direct replacements for the obsolete 0664004.ZRLL based on electrical and mechanical parameter equivalence.

38214000000 (Littelfuse TR5® 382): This part maintains active product status within the Littelfuse portfolio and carries certifications including CCC, cURus, KC, PSE/JET, SEMKO, and VDE. It is available in Cut Tape packaging with high inventory levels (15,542 pcs). The melting I²t value of 72 is marginally lower than the original part (77), and the height dimension is reduced to 8.00mm. These variations remain within acceptable substitution parameters for equivalent thermal and mechanical performance.

0034.6921 (SCHURTER MXT 250): This part is manufactured by SCHURTER Inc. and maintains active product status. It carries certifications including CCC, cURus, KC, PSE/JET, and VDE. Available in Bulk packaging with substantial inventory (4,874 pcs), this part matches the original melting I²t value of 77 and maintains identical height dimensions (8.50mm). DC cold resistance is not specified for this part.

Both parts satisfy all mandatory electrical and mechanical substitution criteria. Selection between them depends on packaging requirements, inventory availability, and supply chain preferences.

Frequently Asked Questions (FAQ)

Q: Can 38214000000 be used as a direct replacement for 0664004.ZRLL?

A: Yes. Both parts share identical current rating (4A), voltage rating (250VAC), response time (Slow Blow), mounting type (Through Hole), fuse type (Board Mount), package style (Radial, Can, Vertical), breaking capacity (100A), and operating temperature range (-40°C ~ 85°C). The 38214000000 is an active product with current manufacturing support.

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

A: The primary differences are manufacturer (Littelfuse vs. SCHURTER), series designation, packaging format (Cut Tape vs. Bulk), and minor dimensional variations. The 38214000000 has a reduced height of 8.00mm compared to 8.50mm for both the original and 0034.6921. The melting I²t value for 38214000000 is 72 versus 77 for both the original and 0034.6921. Both parts meet all electrical and mechanical substitution requirements.

Q: Are there any compliance or certification differences?

A: Both substitute parts are ROHS3 compliant. The 38214000000 carries certifications for CCC, cURus, KC, PSE/JET, SEMKO, and VDE. The 0034.6921 carries certifications for CCC, cURus, KC, PSE/JET, and VDE. Both meet the regulatory requirements of the original part.

Q: Does the dimensional difference in height affect PCB layout compatibility?

A: The 38214000000 has a height of 8.00mm compared to 8.45mm for the original 0664004.ZRLL. The 0034.6921 maintains the original height of 8.50mm. PCB layout compatibility depends on specific clearance requirements in your design. Verify available vertical space before selecting the 38214000000.

Q: What packaging options are available for these substitutes?

A: The 38214000000 is supplied in Cut Tape (CT) packaging. The 0034.6921 is supplied in Bulk packaging. Select based on your procurement and assembly process requirements.

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