3KP40-B Equivalent & Substitute Parts

Part Overview

The 3KP40-B is a unidirectional Transient Voltage Suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose transient voltage protection applications. This component features a 40V reverse standoff voltage, 67.73V maximum clamping voltage, and 3000W peak pulse power rating in a through-hole P600 axial package. The product is currently obsolete, making equivalent and substitute parts necessary for ongoing design support and component procurement.

Substiute Parts

3KP40-B

Littelfuse Inc.In Stock: 9973KP40-B Datasheet

Current PartRFQ

5KP40A-B

Littelfuse Inc.In Stock: 11615KP40A-B Datasheet

DirectRFQ

15KP40A-TP

Micro Commercial CoIn Stock: 107315KP40A-TP Datasheet

MFR RecommendedRFQ

5KP40A-E3/54

Vishay General Semiconductor - Diodes DivisionIn Stock: 17535KP40A-E3/54 Datasheet

MFR RecommendedRFQ

5KP40A-TP

Micro Commercial CoIn Stock: 15365KP40A-TP Datasheet

MFR RecommendedRFQ

5KP40AHE3/54

Vishay General Semiconductor - Diodes DivisionIn Stock: 9485KP40AHE3/54 Datasheet

MFR RecommendedRFQ

5KP40AHE3/73

Vishay General Semiconductor - Diodes DivisionIn Stock: 11765KP40AHE3/73 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 3KP40-B is determined by the following critical parameters:

• Voltage - Reverse Standoff (Typ): Must be 40V to maintain circuit protection threshold
• Voltage - Clamping (Max) @ Ipp: Must not exceed 67.73V to ensure adequate transient suppression
• Unidirectional Channels: Must be 1 (single channel)
• Type: Must be Zener diode
• Mounting Type: Must be Through Hole
• Package / Case: Must be P600 or R-6 axial configuration
• Operating Temperature Range: Must support -55°C ~ 175°C (TJ)

Substitute parts are grouped into two categories based on power rating capability and manufacturer availability:

Category A (5kW Power Rating): 5KP40A-B, 5KP40A-TP, 5KP40A-E3/54, 5KP40AHE3/54, 5KP40AHE3/73 — These parts provide higher peak pulse power (5000W) compared to the original 3000W rating, offering enhanced transient protection margin.

Category B (15kW Power Rating): 15KP40A-TP — This part provides the highest peak pulse power (15000W), suitable for applications requiring maximum transient suppression capability.

Parameter Comparison

Engineering Selection Recommendations

All substitute parts listed maintain the critical 40V reverse standoff voltage and are active products with current manufacturer support, addressing the obsolescence of the 3KP40-B.

For standard applications with ROHS3 compliance requirement: Select 5KP40A-B, 5KP40A-TP, or 5KP40AHE3/73. These parts provide 5000W peak pulse power with full ROHS3 compliance and are available in standard P600 or R-6 axial packages.

For automotive applications: Select 5KP40AHE3/54 or 5KP40AHE3/73. Both parts carry AEC-Q101 automotive qualification and ROHS3 compliance, with 5000W peak pulse power rating.

For maximum transient protection margin: Select 15KP40A-TP, which provides 15000W peak pulse power. This part is ROHS3 compliant and available in R-6 axial package.

For legacy system compatibility with P600 package requirement: Select 5KP40A-B, 5KP40A-E3/54, or 5KP40AHE3/54, all available in P600 axial configuration.

Note: 5KP40A-E3/54 is RoHS non-compliant and should be selected only when legacy compliance status is acceptable for the application.

Frequently Asked Questions (FAQ)

Q: Can I directly replace 3KP40-B with any of the listed substitute parts?

A: Yes, all listed substitute parts meet the critical electrical parameters (40V reverse standoff, clamping voltage ≤ 67.73V, single channel, Zener type) and mounting requirements (through-hole, axial configuration). However, verify package footprint compatibility: P600 and R-6 packages have different physical dimensions.

Q: What is the difference between P600 and R-6 packages?

A: Both are through-hole axial packages for TVS diodes. P600 is the standard Littelfuse package designation, while R-6 is the Micro Commercial Co designation. Physical dimensions differ; verify PCB footprint compatibility before selection.

Q: Why do some substitute parts have higher power ratings (5kW or 15kW) than the original 3KP40-B (3kW)?

A: Higher power ratings provide enhanced transient suppression capability and improved thermal margin. These parts are direct functional substitutes that offer superior performance characteristics while maintaining the same voltage protection threshold.

Q: Are the Vishay 5KP40AHE3 variants suitable for automotive applications?

A: Yes. The 5KP40AHE3/54 and 5KP40AHE3/73 carry AEC-Q101 automotive qualification and are suitable for automotive-grade applications requiring ROHS3 compliance.

Q: What is the significance of the clamping voltage specification?

A: Clamping voltage determines the maximum voltage the TVS diode allows across the protected circuit during a transient event. All substitute parts maintain clamping voltage at or below 67.73V, ensuring equivalent or improved protection performance.

Q: Can I use 15KP40A-TP as a direct replacement in all applications?

A: Yes, 15KP40A-TP meets all critical electrical parameters and is ROHS3 compliant. However, verify R-6 package compatibility with your PCB footprint, as it differs from the original P600 package.

Q: Which substitute part offers the best long-term availability?

A: All listed substitute parts have active product status with current manufacturer support. 5KP40A-B (Littelfuse), 5KP40A-TP (Micro Commercial Co), and 5KP40AHE3/73 (Vishay) represent established manufacturers with strong market presence.