SP4040-02BTG Equivalent & Substitute Parts

Part Overview

The SP4040-02BTG is a steering transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for rail-to-rail protection in Ethernet applications. This component features a 3.3V reverse standoff voltage with 20V clamping capability and 75A peak pulse current handling (8/20µs). The part is currently classified as obsolete, making identification of suitable alternatives essential for ongoing design support and production continuity.

Substiute Parts

SP4040-02BTG

Littelfuse Inc.In Stock: 1760SP4040-02BTG Datasheet

Current PartRFQ

SP2502LBTG

Littelfuse Inc.In Stock: 14753SP2502LBTG Datasheet

DirectRFQ

LC03-6R2G

onsemiIn Stock: 23988LC03-6R2G Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the SP4040-02BTG is determined by the following critical parameters:

Primary Substitution Criteria:

• Steering (Rail to Rail) TVS diode topology with 2 unidirectional channels
• Reverse standoff voltage: 3.3V maximum
• Voltage clamping capability: 20V maximum at peak pulse current
• Peak pulse current handling: minimum 75A (8/20µs)
• Surface mount package: 8-SOIC form factor (0.154", 3.90mm width)
• Operating temperature range: minimum -55°C to 125°C

Secondary Compatibility Factors:

• RoHS3 compliance
• Moisture sensitivity level MSL 1 (unlimited)
• Power line protection capability (where applicable)

Substitute parts must satisfy all primary criteria to ensure functional equivalence in the original application circuit.

Parameter Comparison

Engineering Selection Recommendations

SP2502LBTG (Direct Substitute - Littelfuse Inc.)

The SP2502LBTG is the primary direct substitute for the obsolete SP4040-02BTG. Both components share identical electrical specifications: 3.3V reverse standoff voltage, 20V clamping voltage, and 75A peak pulse current. The SP2502LBTG maintains the same 8-SOIC package footprint and RoHS3 compliance. The key difference is product status: SP2502LBTG is active and in production, with 14,654 units currently in stock. The operating temperature range is slightly narrower (-40°C to 125°C versus -55°C to 125°C), which may require thermal evaluation for applications requiring full -55°C operation. This substitute is recommended for direct replacement in existing designs.

LC03-6R2G (Alternative Substitute - onsemi)

The LC03-6R2G is an alternative substitute manufactured by onsemi, offering active product status and extended operating temperature range (-55°C to 150°C). This component maintains the same 8-SOIC package and 20V clamping voltage. However, the LC03-6R2G differs in voltage specifications: 5V reverse standoff (versus 3.3V) and 6.8V breakdown voltage (versus 3.3V). The peak pulse current is higher at 100A (versus 75A), and capacitance is elevated at 16pF (versus 5pF). These parameter differences indicate the LC03-6R2G is suitable only for applications where the higher voltage ratings and capacitance do not conflict with circuit requirements. This substitute is recommended only when the voltage and capacitance specifications are compatible with the target application.

Frequently Asked Questions (FAQ)

Q: Can SP2502LBTG be used as a direct replacement for SP4040-02BTG?

A: Yes. The SP2502LBTG is electrically equivalent to the SP4040-02BTG across all critical parameters: 3.3V reverse standoff voltage, 20V clamping voltage, 75A peak pulse current, and identical 8-SOIC package. Both are RoHS3 compliant with MSL 1 rating. The primary consideration is the operating temperature range: SP2502LBTG operates from -40°C to 125°C, while SP4040-02BTG operates from -55°C to 125°C. Applications requiring operation below -40°C require thermal analysis or alternative selection.

Q: What are the key differences between SP2502LBTG and LC03-6R2G?

A: Both are active products in 8-SOIC packages with 20V clamping voltage. SP2502LBTG matches the original SP4040-02BTG voltage specifications (3.3V standoff, 3.3V breakdown), while LC03-6R2G has higher voltage ratings (5V standoff, 6.8V breakdown). LC03-6R2G provides higher peak pulse current (100A versus 75A) and extended temperature range (-55°C to 150°C). LC03-6R2G also has higher capacitance (16pF versus 5pF at 1MHz). Selection depends on whether the application circuit tolerates these parameter differences.

Q: Are all substitute parts available in the same packaging format?

A: All three parts use the 8-SOIC (0.154", 3.90mm width) surface mount package, ensuring identical PCB footprint compatibility. Packaging availability differs: SP4040-02BTG was supplied in standard packaging (status obsolete), SP2502LBTG is available in Tape & Reel format, and LC03-6R2G is available in Cut Tape and Digi-Reel formats. These packaging differences do not affect electrical performance or board-level compatibility.

Q: Which substitute is recommended for new designs?

A: SP2502LBTG is recommended for new designs requiring direct electrical equivalence to SP4040-02BTG specifications. This part is active, in production, and maintains identical voltage and current ratings. LC03-6R2G is recommended only when the higher voltage ratings, increased current capacity, and extended temperature range provide design advantages that offset the parameter differences from the original specification.

Q: Do all parts meet RoHS3 compliance requirements?

A: Yes. SP4040-02BTG, SP2502LBTG, and LC03-6R2G are all RoHS3 compliant. All three parts carry MSL 1 (unlimited) moisture sensitivity rating, indicating no special moisture control requirements during storage or handling.