Littelfuse 0452005.NRL Surface Mount Fuse – Equivalent & Substitute Parts

Part Overview

The Littelfuse 0452005.NRL is a 5 A, 125 V AC/DC surface mount board fuse in the NANO²® 452 series. This slow-blow fuse is designed for board-level protection in applications requiring 2-SMD, square end block packaging. The part is active and widely stocked, with 4,905 units available. Substitute parts are identified when packaging options, series variants, or inventory availability require alternative sourcing while maintaining identical electrical and mechanical specifications.

Key Parameters

Parameter	Value
Current Rating	5 A
Voltage Rating (AC)	125 V
Voltage Rating (DC)	125 V
Response Time	Slow Blow
Package / Case	2-SMD, Square End Block
Mounting Type	Surface Mount
Breaking Capacity @ Rated Voltage	50 A
Operating Temperature Range	-55°C to 125°C
Size / Dimension	0.240" L × 0.106" W × 0.106" H (6.10 mm × 2.69 mm × 2.69 mm)
DC Cold Resistance	0.0136 Ohms
Melting I²t	53.72
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitute parts for the 0452005.NRL are qualified based on the following criteria:

Electrical Parameters (Must Match):

Current Rating: 5 A
Voltage Rating: 125 V AC / 125 V DC
Response Time: Slow Blow
Breaking Capacity: 50 A
Melting I²t: 53.72

Mechanical Parameters (Must Match):

Package / Case: 2-SMD, Square End Block
Size / Dimension: 0.240" L × 0.106" W × 0.106" H (6.10 mm × 2.69 mm × 2.69 mm)
Mounting Type: Surface Mount

Allowed Variations:

Packaging format (Tape & Reel vs. Cut Tape & Digi-Reel®)
Series designation (NANO²® 452, NANO²® 449, NANO²® 454)
Approval agency certifications (CSA, PSE, UR, cULus, UL, METI)
DC Cold Resistance tolerance (0.0136 Ohms to 0.0171 Ohms)
Inventory availability

Parameter Comparison

Part Number	Manufacturer	Series	Current (A)	Voltage AC (V)	Voltage DC (V)	Response Time	Package	Breaking Capacity (A)	Melting I²t	DC Cold Resistance (Ω)	Packaging Format	Inventory (Pcs)
0452005.NRL	Littelfuse Inc.	NANO²® 452	5	125	125	Slow Blow	2-SMD, Square End Block	50	53.72	0.0136	Tape & Reel (TR)	4,905
0449005.MR	Littelfuse	NANO²® 449	5	125	125	Slow Blow	2-SMD, Square End Block	50	59.59	0.0171	Cut Tape (CT) & Digi-Reel®	1,382
0452005.MRL	Littelfuse Inc.	NANO²® 452	5	125	125	Slow Blow	2-SMD, Square End Block	50	53.72	0.0136	Cut Tape (CT) & Digi-Reel®	348,006
0452005.MRSN	Littelfuse	NANO²® 452	5	125	125	Slow Blow	2-SMD, Square End Block	50	53.72	0.0136	Tape & Reel (TR)	3,400
0454005.MR	Littelfuse	NANO²® 454	5	125	125	Slow Blow	2-SMD, Square End Block	50	53.72	0.0136	Tape & Reel (TR)	10,100
0454005.NR	Littelfuse Inc.	NANO²® 454	5	125	125	Slow Blow	2-SMD, Square End Block	50	53.72	0.0136	Tape & Reel (TR)	10,666

Engineering Selection Recommendations

Primary Substitutes (Identical Electrical & Mechanical Specifications):

0452005.MRL and 0452005.MRSN are direct substitutes for 0452005.NRL. Both maintain identical current rating, voltage rating, melting I²t, and DC cold resistance. The difference is packaging format: 0452005.MRL is supplied in Cut Tape & Digi-Reel® format with significantly higher inventory (348,006 units), while 0452005.MRSN is supplied in Tape & Reel format. Both carry CSA, PSE, and UR certifications matching the original part.

Series Variants (NANO²® 454):

0454005.MR and 0454005.NR are NANO²® 454 series equivalents with identical electrical performance and physical dimensions. Both maintain 5 A, 125 V AC/DC ratings, 50 A breaking capacity, and 53.72 melting I²t. Certifications include CSA, PSE, and UL. These parts are suitable for applications where NANO²® 454 series qualification is acceptable.

Alternative Series (NANO²® 449):

0449005.MR is a NANO²® 449 series equivalent with matching electrical ratings and physical dimensions. This part exhibits a higher melting I²t value (59.59 versus 53.72) and slightly elevated DC cold resistance (0.0171 Ohms versus 0.0136 Ohms). Certifications are cULus and PSE. Selection of this part requires confirmation that the thermal response characteristics are compatible with the application.

Inventory Considerations:

When primary substitutes are unavailable, 0454005.MR (10,100 units) and 0454005.NR (10,666 units) offer the highest inventory availability among NANO²® 454 variants.

Frequently Asked Questions (FAQ)

Q: Can 0452005.MRL be used as a direct replacement for 0452005.NRL?

A: Yes. Both parts are NANO²® 452 series fuses with identical electrical ratings (5 A, 125 V AC/DC), melting I²t (53.72), DC cold resistance (0.0136 Ohms), and physical dimensions (0.240" × 0.106" × 0.106"). The only difference is packaging format: 0452005.MRL is supplied in Cut Tape & Digi-Reel® format, while 0452005.NRL is supplied in Tape & Reel format. Both are suitable for surface mount board assembly.

Q: What is the difference between NANO²® 452, 449, and 454 series fuses?

A: All three series maintain the same electrical ratings (5 A, 125 V AC/DC) and physical dimensions for this product line. The NANO²® 449 series exhibits a higher melting I²t (59.59) and slightly elevated DC cold resistance (0.0171 Ohms) compared to NANO²® 452 and 454 series (both 53.72 and 0.0136 Ohms). Series selection depends on application thermal response requirements and certification compliance.

Q: Are there certification differences between substitute parts?

A: Yes. The original 0452005.NRL carries CSA, PSE, and UR certifications. Substitute 0452005.MRL and 0452005.MRSN maintain the same certifications. NANO²® 454 variants (0454005.MR and 0454005.NR) carry CSA, PSE, and UL certifications. The NANO²® 449 variant (0449005.MR) carries cULus and PSE certifications. Verify that the selected part's certifications meet application and regional compliance requirements.

Q: Can I use 0449005.MR as a substitute?

A: 0449005.MR is electrically and mechanically compatible with 0452005.NRL for the core 5 A, 125 V AC/DC protection function. However, it exhibits different thermal characteristics: melting I²t of 59.59 (versus 53.72) and DC cold resistance of 0.0171 Ohms (versus 0.0136 Ohms). Certification coverage is also different (cULus and PSE versus CSA, PSE, and UR). Use this part only when application requirements and certifications are confirmed compatible.

Q: What packaging formats are available?

A: Substitute parts are available in two packaging formats: Tape & Reel (TR) and Cut Tape & Digi-Reel® (CT). Tape & Reel format is suitable for high-volume automated assembly. Cut Tape & Digi-Reel® format is suitable for lower-volume or mixed-component assembly. Selection depends on production volume and assembly equipment compatibility.

Q: Which substitute has the highest inventory availability?

A: 0452005.MRL has the highest inventory with 348,006 units in stock. This part is a direct electrical and mechanical equivalent to 0452005.NRL, supplied in Cut Tape & Digi-Reel® format.

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