Littelfuse 046702.5NR Surface Mount Board Mount Fuse 2.5A 32V AC/DC 0603

Part Overview

The Littelfuse 046702.5NR is a surface mount board mount fuse rated for 2.5 A at 32 V AC/DC with fast blow response time in 0603 (1608 Metric) package. This component is Active status and widely used in circuit protection applications requiring compact form factor and reliable overcurrent protection. Equivalent and substitute parts are identified based on matching electrical ratings, mechanical compatibility, and thermal characteristics to ensure direct functional replacement in PCB designs.

Key Parameters

Parameter	046702.5NR Specification
Manufacturer	Littelfuse Inc.
Current Rating	2.5 A
Voltage Rating - AC	32 V
Voltage Rating - DC	32 V
Response Time	Fast Blow
Package / Case	0603 (1608 Metric)
Mounting Type	Surface Mount
Fuse Type	Board Mount (Cartridge Style Excluded)
Breaking Capacity @ Rated Voltage	35 A
Operating Temperature Range	-55°C ~ 90°C
DC Cold Resistance	0.021 Ohms
Approval Agency	CSA, UL
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitute parts for the 046702.5NR are grouped based on the following critical parameters that determine functional equivalence:

Primary Matching Criteria:

Current Rating: 2.5 A (exact match required)
Package / Case: 0603 (1608 Metric) (exact match required)
Mounting Type: Surface Mount (exact match required)
Response Time: Fast Blow (exact match required)
Fuse Type: Board Mount (Cartridge Style Excluded) (exact match required)

Secondary Compatibility Criteria:

Voltage Rating - AC: 32 V minimum
Voltage Rating - DC: 32 V minimum (higher ratings acceptable for DC-only applications)
Operating Temperature Range: Must support -55°C minimum and 90°C maximum
Approval Agencies: CSA, UL, cURus, or CE certifications acceptable
RoHS Status: ROHS3 Compliant required

Substitutes are classified as direct equivalents when all primary criteria and voltage ratings match exactly. Parts with higher DC voltage ratings (63 V) are acceptable substitutes when circuit design permits, as they provide enhanced protection margin without affecting AC circuit performance.

Parameter Comparison

Part Number	Manufacturer	Current Rating (A)	Voltage AC (V)	Voltage DC (V)	Response Time	Package	Breaking Capacity (A)	DC Cold Resistance (Ohms)	Operating Temp (°C)	Approval Agency
046702.5NR	Littelfuse Inc.	2.5	32	32	Fast Blow	0603	35	0.021	-55 ~ 90	CSA, UL
046702.5NRHF	Littelfuse Inc.	2.5	32	32	Fast Blow	0603	35	0.021	-55 ~ 90	CSA, UL
TR/0603FA2.5-R	Eaton - Electronics Division	2.5	32	32	Fast Blow	0603	35	0.037	-55 ~ 125	CSA, UL
SF-0603F250-2	Bourns Inc.	2.5	32	32	Fast Blow	0603	50	0.024	-20 ~ 105	UL
C2Q 2.5	Bel Fuse Inc.	2.5	32	63	Fast Blow	0603	35 AC, 50 DC	0.041	-55 ~ 125	CE, cURus
3412.0120.22	SCHURTER Inc.	2.5	32	63	Fast Blow	0603	50	0.0235	-55 ~ 90	cURus
3412.0120.24	SCHURTER Inc.	2.5	32	63	Fast Blow	0603	50	0.0235	-55 ~ 90	cURus
F0603E2R50FSTR	KYOCERA AVX	2.5	N/A	32	Fast Blow	0603	50	0.035	-55 ~ 125	cUL, UL
MFU0603FF02500P100	Vishay Beyschlag/Draloric/BC Components	2.5	N/A	32	Fast Blow	0603	50	0.037	-55 ~ 125	UL

Engineering Selection Recommendations

Parametric Equivalent (Direct Replacement): The 046702.5NRHF from Littelfuse Inc. is a parametric equivalent with identical electrical and mechanical specifications to the 046702.5NR. Both parts carry CSA and UL approvals and are ROHS3 compliant. This part provides the highest compatibility assurance for direct substitution.

Direct Equivalents (32V AC/DC Rating): The TR/0603FA2.5-R (Eaton) and SF-0603F250-2 (Bourns) are direct functional equivalents with matching 32 V AC/DC ratings and 0603 package. Both are ROHS3 compliant and carry appropriate regulatory approvals (CSA/UL for Eaton; UL for Bourns). The Eaton part extends operating temperature to 125°C, providing enhanced thermal margin. The Bourns part offers higher breaking capacity (50 A) and lower DC cold resistance (0.024 Ohms).

Higher DC Voltage Substitutes (32V AC / 63V DC Rating): The C2Q 2.5 (Bel Fuse), 3412.0120.22, and 3412.0120.24 (SCHURTER) provide enhanced DC voltage protection at 63 V while maintaining 32 V AC rating. These parts are suitable for applications where circuit design permits higher DC voltage margin. All three are ROHS3 compliant with appropriate regulatory certifications (CE/cURus for Bel Fuse; cURus for SCHURTER).

DC-Only Rated Substitutes (32V DC): The F0603E2R50FSTR (KYOCERA AVX) and MFU0603FF02500P100 (Vishay) are rated for 32 V DC only without AC rating specification. These parts are suitable only for DC circuit applications and should not be used in AC or mixed AC/DC circuits. Both are ROHS3 compliant with UL or cUL/UL approvals and support extended operating temperature to 125°C.

Product Status Consideration: All listed substitute parts maintain Active product status, ensuring continued availability and manufacturing support.

Frequently Asked Questions (FAQ)

Q: Can I substitute the 046702.5NR with a part rated for 63V DC instead of 32V DC? A: Yes. Parts such as C2Q 2.5, 3412.0120.22, and 3412.0120.24 with 63V DC rating are acceptable substitutes. The higher DC voltage rating provides additional protection margin and does not compromise circuit performance in applications designed for 32V DC operation.

Q: Are DC-only rated fuses (F0603E2R50FSTR, MFU0603FF02500P100) suitable replacements? A: No, not for all applications. These parts lack AC voltage rating and must be used only in DC circuits. If your circuit operates in AC or mixed AC/DC mode, use only parts with matching 32V AC rating such as 046702.5NRHF, TR/0603FA2.5-R, or SF-0603F250-2.

Q: What is the significance of DC Cold Resistance variation among substitutes? A: DC cold resistance affects voltage drop across the fuse during normal operation. The 046702.5NR has 0.021 Ohms. Substitutes range from 0.0235 to 0.041 Ohms. Higher resistance increases power dissipation and heat generation. For applications with tight thermal budgets or high continuous current near the 2.5A rating, select substitutes with lower DC cold resistance (0.021-0.024 Ohms).

Q: Does operating temperature range affect substitution compatibility? A: Operating temperature range must support your application's thermal environment. The 046702.5NR operates -55°C to 90°C. Substitutes with extended range (-55°C to 125°C) such as TR/0603FA2.5-R, C2Q 2.5, F0603E2R50FSTR, and MFU0603FF02500P100 provide enhanced thermal margin. Parts with limited range such as SF-0603F250-2 (-20°C to 105°C) require verification against your minimum operating temperature requirement.

Q: What approval agencies are acceptable for substitution? A: The 046702.5NR carries CSA and UL approvals. Acceptable substitute approvals include CSA, UL, cURus, and CE. All listed substitutes meet these criteria. Verify that your application's regulatory requirements align with the substitute part's approval agency certifications.

Q: Is the 046702.5NRHF identical to the 046702.5NR? A: Yes. The 046702.5NRHF is a parametric equivalent with identical current rating, voltage ratings, response time, package, breaking capacity, DC cold resistance, operating temperature range, and approval agencies. Both are ROHS3 compliant and from the same manufacturer.

Q: Can I use a substitute with higher breaking capacity? A: Yes. Parts with higher breaking capacity (50A vs. 35A) such as SF-0603F250-2, 3412.0120.22, 3412.0120.24, F0603E2R50FSTR, and MFU0603FF02500P100 provide enhanced fault current handling capability. This does not affect normal circuit operation and improves safety margin in high fault current environments.

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