3KP40C-B Equivalent & Substitute Parts

Part Overview

The 3KP40C-B is a transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection applications. This component features a 40V reverse standoff voltage with a 67.73V maximum clamping voltage and 46.5A peak pulse current capability in a through-hole P600 axial package. The product is currently obsolete, making identification of suitable equivalent parts essential for ongoing system support, maintenance, and new design implementations where this protection topology is required.

Substiute Parts

3KP40C-B

Littelfuse Inc.In Stock: 11413KP40C-B Datasheet

Current PartRFQ

5KP40CA-B

Littelfuse Inc.In Stock: 9105KP40CA-B Datasheet

DirectRFQ

15KPA40CAE3/TR13

Microchip TechnologyIn Stock: 98715KPA40CAE3/TR13 Datasheet

MFR RecommendedRFQ

3KP40CA-TP

Micro Commercial CoIn Stock: 10913KP40CA-TP Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 3KP40C-B is determined by the following critical parameters that must remain within acceptable tolerances:

• Voltage - Reverse Standoff (Typ): Must be 40V to maintain circuit protection thresholds
• Voltage - Clamping (Max) @ Ipp: Must not exceed 67.73V to prevent overstress on protected components
• Current - Peak Pulse (10/1000µs): Must meet or exceed 46.5A to handle transient events
• Power - Peak Pulse: Must support 3000W minimum dissipation capability
• Operating Temperature Range: Must span -55°C ~ 175°C (TJ)
• Mounting Type & Package: Through-hole axial configuration required for mechanical compatibility
• RoHS Compliance: ROHS3 Compliant status required for regulatory alignment

The identified substitute parts are grouped into two categories: direct functional equivalents from Littelfuse Inc. and manufacturer-recommended alternatives from Microchip Technology and Micro Commercial Co that meet or exceed the electrical and mechanical requirements of the original component.

Parameter Comparison

Engineering Selection Recommendations

5KP40CA-B (Littelfuse Inc.) is the primary direct substitute. This active-status component maintains identical reverse standoff voltage (40V) and operating temperature range while providing improved clamping voltage (64.5V vs 67.73V) and higher peak pulse current (79.1A vs 46.5A). The 5kW peak pulse power rating exceeds the original 3kW specification, offering enhanced transient protection margin. Both components use the P600 axial package and maintain ROHS3 compliance, ensuring mechanical and regulatory compatibility.

15KPA40CAE3/TR13 (Microchip Technology) serves as an alternative for applications requiring higher transient energy absorption. This component meets all critical voltage parameters (40V standoff, 65.8V clamping) and operating temperature requirements while delivering significantly higher peak pulse current (229.5A) and 15kW power dissipation capability. The tape & reel packaging format suits high-volume production environments. ROHS3 compliance and REACH unaffected status confirm regulatory alignment.

3KP40CA-TP (Micro Commercial Co) provides a functionally equivalent option with matching reverse standoff voltage (40V), clamping voltage (64.5V), and peak pulse current (46.5A) to the original component. Operating temperature range and power dissipation (3kW) align with the 3KP40C-B specification. The R-6 axial package differs from the original P600 package; mechanical fit verification is required before implementation. Active product status ensures ongoing availability.

Frequently Asked Questions (FAQ)

Q: Can the 5KP40CA-B directly replace the 3KP40C-B without circuit modification?

A: Yes. Both components share identical reverse standoff voltage (40V), operating temperature range (-55°C ~ 175°C), and through-hole axial mounting configuration. The 5KP40CA-B provides superior clamping voltage performance (64.5V vs 67.73V) and higher peak pulse current capability (79.1A vs 46.5A), making it a direct functional upgrade. The P600 package ensures mechanical compatibility.

Q: What is the difference between the P600 and R-6 packages used in these TVS diodes?

A: Both P600 and R-6 are through-hole axial package designations for diodes. The 3KP40CA-TP uses the R-6 package while the original 3KP40C-B and other primary substitutes use P600. Physical dimensions and lead spacing may differ; mechanical fit verification in the target PCB is required before selecting the R-6 variant.

Q: Why does the 15KPA40CAE3/TR13 have significantly higher peak pulse current (229.5A) than the original?

A: The 15KPA40CAE3/TR13 belongs to the 15kW power class TVS diode family, compared to the 3kW class of the original 3KP40C-B. Higher peak pulse current capability reflects the component's enhanced transient energy absorption capacity. This provides additional protection margin in applications subject to severe transient events, though it is not required for direct functional replacement.

Q: Are all substitute parts ROHS3 compliant?

A: The 5KP40CA-B and 15KPA40CAE3/TR13 are explicitly ROHS3 compliant. The 3KP40CA-TP RoHS status is not specified in the provided data. Verification with the manufacturer is recommended if ROHS3 compliance is a regulatory requirement for your application.

Q: Can the 3KP40C-B be used in new designs, or should substitutes be specified?

A: The 3KP40C-B is obsolete and should not be specified for new designs. The 5KP40CA-B (active status, Littelfuse Inc.) is the recommended primary substitute for new implementations, offering improved performance characteristics and guaranteed long-term availability.