Littelfuse 39912000000 Equivalent & Substitute Parts

Part Overview

The Littelfuse 39912000000 is a 2A board mount fuse rated for 65V AC/DC operation with slow blow response characteristics. This through-hole radial fuse is designed for circuit protection in applications requiring moderate voltage and current ratings. The part maintains active product status with cULus approval and ROHS3 compliance. Substitute parts are identified when equivalent electrical performance can be achieved within the specified parameter constraints of the application.

Substiute Parts

39912000000

Littelfuse Inc.In Stock: 110639912000000 Datasheet

Current PartRFQ

0697W2000-02

Bel Fuse Inc.In Stock: 66660697W2000-02 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

The Bel Fuse Inc. 0697W2000-02 qualifies as a substitute based on the following matched electrical and mechanical parameters:

Matched Parameters:

• Current Rating: 2 A (identical)
• Response Time: Slow Blow (identical)
• Mounting Type: Through Hole (identical)
• Package / Case: Radial, Box (identical)
• Physical Dimensions: 0.329" L x 0.157" W x 0.307" H versus 0.335" L x 0.157" W x 0.315" H (within tolerance for board mount applications)

Enhanced Parameters in Substitute:

• Voltage Rating - AC: 350 V (exceeds 65 V requirement)
• Voltage Rating - DC: 72 V (exceeds 65 V requirement)
• Breaking Capacity: 100 A (exceeds 50 A requirement)
• Operating Temperature Range: -55°C ~ 125°C (broader than -40°C ~ 85°C)

The substitute part maintains backward compatibility for applications operating at or below the original part's voltage and current specifications while providing enhanced performance margins.

Parameter Comparison

Engineering Selection Recommendations

Primary Part Selection (Littelfuse 39912000000): Select when application voltage and current requirements are limited to 65V AC/DC at 2A maximum. This part carries cULus approval and is suitable for consumer and industrial applications within the specified temperature range of -40°C to 85°C.

Substitute Part Selection (Bel Fuse 0697W2000-02): Select when higher voltage margins are required or when operating temperature range must extend to -55°C or above 85°C. This part carries multiple certifications including AEC-Q200, CQC, cURus, PSE, and VDE, providing broader compliance coverage for automotive and international applications. The enhanced breaking capacity of 100A provides additional protection margin in high-fault-current environments.

Both parts maintain ROHS3 compliance and REACH unaffected status. Selection between these parts depends on application voltage headroom requirements and certification needs rather than functional performance at rated specifications.

Frequently Asked Questions (FAQ)

Q: Can the Bel Fuse 0697W2000-02 be used as a direct replacement for the Littelfuse 39912000000?

A: Yes, within applications operating at or below 65V AC/DC and 2A. The substitute part's higher voltage ratings (350V AC / 72V DC) and enhanced breaking capacity provide backward compatibility. Physical dimensions are within tolerance for standard through-hole board mount applications.

Q: What is the primary difference between these two fuse parts?

A: The main differences are voltage rating headroom and operating temperature range. The Bel Fuse part provides 350V AC versus 65V AC and extends the operating temperature range to -55°C ~ 125°C. Both maintain identical current rating (2A) and response time (Slow Blow).

Q: Are there packaging differences between these parts?

A: The Littelfuse part is supplied in Tape & Box packaging, while the Bel Fuse part is supplied in Cut Tape packaging. Both use identical Radial, Box case style suitable for through-hole board mount applications.

Q: Which certifications should I consider for my application?

A: The Littelfuse part carries cULus approval. The Bel Fuse substitute carries AEC-Q200, CQC, cURus, PSE, and VDE certifications. Select based on your regional and industry compliance requirements.

Q: Does the higher DC cold resistance of the substitute part affect circuit performance?

A: The Bel Fuse part has 0.032 Ohms versus 0.023 Ohms for the Littelfuse part. This 0.009 Ohm difference is negligible in typical circuit protection applications and does not affect fuse operation or trip characteristics at rated current.