3KP40CA-B Transient Voltage Suppressor - Equivalent & Substitute Parts

Part Overview

The 3KP40CA-B is a bidirectional Zener transient voltage suppressor (TVS) diode manufactured by Littelfuse, designed for general-purpose overvoltage protection applications. This component features a 40V reverse standoff voltage with a 64.5V maximum clamping voltage and 46.5A peak pulse current capability in a through-hole P600 axial package. The product is currently classified as obsolete, making identification of suitable substitute components essential for ongoing design support and procurement continuity.

Substiute Parts

3KP40CA-B

LittelfuseIn Stock: 9603KP40CA-B Datasheet

Current PartRFQ

5KP40CA-B

Littelfuse Inc.In Stock: 9105KP40CA-B Datasheet

DirectRFQ

3KP40CA-TP

Micro Commercial CoIn Stock: 10913KP40CA-TP Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute components for the 3KP40CA-B are selected based on strict electrical and mechanical parameter alignment. The primary substitution criteria are:

Critical Matching Parameters:

• Voltage - Reverse Standoff: 40V (nominal)
• Voltage - Breakdown (Min): 44.4V
• Voltage - Clamping (Max) @ Ipp: 64.5V
• Bidirectional Channels: 1
• Type: Zener
• Operating Temperature Range: -55°C to 175°C
• Mounting Type: Through Hole
• Package compatibility: P600 or R-6 axial packages

Allowable Variation:

• Current - Peak Pulse: Components with equal or greater current rating (46.5A minimum)
• Power - Peak Pulse: Components with equal or greater power dissipation (3000W minimum)

The 3KP40CA-B has two identified substitutes that meet these criteria while offering improved or equivalent performance characteristics and active product status.

Parameter Comparison

Engineering Selection Recommendations

5KP40CA-B (Littelfuse Inc.): This substitute maintains identical voltage specifications and package form factor (P600 axial) while offering enhanced current handling (79.1A versus 46.5A) and increased power dissipation capability (5000W versus 3000W). The component carries active product status and ROHS3 compliance. Direct mechanical and electrical compatibility is confirmed for applications requiring the original 3KP40CA-B performance envelope.

3KP40CA-TP (Micro Commercial Co): This substitute provides electrical parameter equivalence with identical voltage ratings and current specifications (46.5A) and power dissipation (3000W). The component uses an R-6 axial package instead of P600, requiring mechanical board layout verification. Active product status and ROHS3 compliance are confirmed. This option is suitable for designs where package footprint accommodation is feasible.

Both substitutes are ROHS3 compliant and carry active product status, providing long-term procurement stability compared to the obsolete 3KP40CA-B.

Frequently Asked Questions (FAQ)

Q: Can the 5KP40CA-B directly replace the 3KP40CA-B in existing designs?

A: Yes. The 5KP40CA-B maintains identical voltage specifications (40V standoff, 44.4V breakdown, 64.5V clamping) and uses the same P600 axial through-hole package. The increased current rating (79.1A) and power dissipation (5000W) provide enhanced protection margin without affecting circuit compatibility.

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

A: Both are axial through-hole packages for TVS diodes. The P600 and R-6 designations refer to different physical form factors. Board layout and lead spacing must be verified when substituting between these package types.

Q: Are all three components ROHS3 compliant?

A: Yes. The 3KP40CA-B (main part), 5KP40CA-B, and 3KP40CA-TP all carry ROHS3 compliance certification.

Q: Why is the 3KP40CA-B classified as obsolete?

A: Product obsolescence is determined by manufacturer lifecycle decisions. The 5KP40CA-B and 3KP40CA-TP maintain active status and provide equivalent or superior performance for the same application requirements.

Q: What are the critical parameters for TVS diode substitution?

A: Reverse standoff voltage, breakdown voltage, clamping voltage, peak pulse current, and operating temperature range must match or exceed the original specification. Package type and mounting method must be compatible with board design.

Q: Can the 3KP40CA-TP be used if board space is limited?

A: The R-6 package may have different lead spacing than the P600 package. Physical compatibility must be confirmed against your specific PCB layout before substitution.