Littelfuse 0438003.WR Surface Mount Fuse - Equivalent & Substitute Parts

Part Overview

The Littelfuse 0438003.WR is a 3 A, 12 V AC / 32 V DC surface mount board fuse in 0603 (1608 Metric) package with fast-blow response characteristics. This part is classified as obsolete, making identification of active equivalent and substitute components essential for ongoing design support and procurement continuity. The part carries CSA and UL approvals and operates across -55°C to 150°C.

Key Parameters

Parameter	Value
Current Rating	3 A
Voltage Rating - AC	12 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	50 A
Operating Temperature Range	-55°C ~ 150°C
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution eligibility for the 0438003.WR is determined by the following critical parameters:

Current Rating: 3 A (exact match required)
Voltage Rating - DC: 32 V (minimum requirement)
Package / Case: 0603 (1608 Metric) (exact match required for PCB compatibility)
Mounting Type: Surface Mount (exact match required)
Response Time: Fast Blow (exact match required)
Breaking Capacity: 50 A (minimum requirement)

The substitute parts listed below meet these core electrical and mechanical criteria, enabling direct functional replacement in applications designed for the 0438003.WR.

Parameter Comparison

Parameter	0438003.WR (Main)	0438003.WRGT (Littelfuse)	CC06H3A-TR (Eaton)
Manufacturer	Littelfuse Inc.	Littelfuse Inc.	Eaton - Electronics Division
Current Rating (Amps)	3 A	3 A	3 A
Voltage Rating - AC	12 V	12 V	Not specified
Voltage Rating - DC	32 V	32 V	32 V
Response Time	Fast Blow	Fast Blow	Fast Blow
Package / Case	0603 (1608 Metric)	0603 (1608 Metric)	0603 (1608 Metric)
Mounting Type	Surface Mount	Surface Mount	Surface Mount
Breaking Capacity @ Rated Voltage	50 A	50 A AC, 50 A DC	50 A
Operating Temperature Range	-55°C ~ 150°C	-55°C ~ 150°C	-40°C ~ 85°C
DC Cold Resistance (Ohms)	0.0252	0.0264	0.027
Melting I²t	0.2922	0.439	0.3
Product Status	Obsolete	Active	Active
Approval Agency	CSA, UL	CSA, cURus	cULus
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	RoHS Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

0438003.WRGT (Littelfuse Inc.) is the primary substitute for the obsolete 0438003.WR. Both parts are manufactured by Littelfuse and share identical electrical ratings, package dimensions, and operating temperature range. The 0438003.WRGT maintains active product status with higher inventory availability and carries CSA and cURus certifications. The melting I²t value of 0.439 differs from the original 0.2922, reflecting design improvements in the active series.

CC06H3A-TR (Eaton - Electronics Division) is an alternative substitute meeting all critical electrical and mechanical parameters. This part is manufactured by Eaton and carries cULus certification. The operating temperature range is restricted to -40°C ~ 85°C compared to the original -55°C ~ 150°C specification. Selection of this part requires confirmation that the reduced temperature range is acceptable for the target application. The melting I²t value of 0.3 is closer to the original specification than the Littelfuse alternative.

Both substitute parts are RoHS compliant and carry MSL 1 (Unlimited) moisture sensitivity ratings, matching the original part's environmental compliance profile.

Frequently Asked Questions (FAQ)

Q: Can 0438003.WRGT be used as a direct replacement for 0438003.WR?

A: Yes. Both parts share identical current rating (3 A), voltage ratings (12 V AC / 32 V DC), package (0603), mounting type (surface mount), and response time (fast blow). The primary difference is product status: 0438003.WR is obsolete while 0438003.WRGT is active. Electrical performance differences (melting I²t, DC cold resistance) are within acceptable substitution tolerances for board-level fuse applications.

Q: What are the temperature limitations when using CC06H3A-TR?

A: The CC06H3A-TR operates within -40°C ~ 85°C, compared to the original part's -55°C ~ 150°C range. Applications requiring operation below -40°C or above 85°C must use 0438003.WRGT or confirm that the Eaton part's temperature range is sufficient for the specific use case.

Q: Are all substitute parts RoHS compliant?

A: Yes. Both 0438003.WRGT and CC06H3A-TR are RoHS compliant. The original 0438003.WR is ROHS3 compliant, while CC06H3A-TR carries standard RoHS compliance. Both meet current environmental regulations for electronic component manufacturing.

Q: What is the significance of the melting I²t difference between parts?

A: Melting I²t defines the thermal energy required to melt the fuse element. The original 0438003.WR has a melting I²t of 0.2922, while 0438003.WRGT is 0.439 and CC06H3A-TR is 0.3. These differences reflect design variations in fuse element composition and geometry. All three parts maintain the same 3 A current rating and fast-blow response, making them functionally equivalent for standard board-level protection applications.

Q: Can these parts be used interchangeably on the same PCB?

A: Yes. All three parts use identical 0603 (1608 Metric) package dimensions and surface mount footprints. PCB layout and reflow soldering processes require no modification when substituting between these parts.

Q: Which certifications should I verify for my application?

A: The original 0438003.WR carries CSA and UL approvals. Substitute 0438003.WRGT carries CSA and cURus certifications. Substitute CC06H3A-TR carries cULus certification. Verify that the certifications of your selected substitute part align with your application's regulatory requirements and end-market standards.

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