Littelfuse 3KP40 Transient Voltage Suppressor Equivalent & Substitute Parts

Part Overview

The Littelfuse 3KP40 is a unidirectional Zener-type transient voltage suppressor (TVS) diode designed for general-purpose overvoltage protection applications. This component features a 40V reverse standoff voltage rating with a maximum clamping voltage of 67.73V at peak pulse current. The 3KP40 is mounted in a P600 axial through-hole package and is rated for 3000W peak pulse power dissipation across an operating temperature range of -55°C to 175°C.

The 3KP40 is classified as obsolete. Equivalent and substitute parts are available from alternative manufacturers with active product status, offering improved availability and extended production support while maintaining compatibility with the original electrical and mechanical specifications.

Substiute Parts

3KP40

LittelfuseIn Stock: 10973KP40 Datasheet

Current PartRFQ

5KP40A

Diotec SemiconductorIn Stock: 34645KP40A Datasheet

DirectRFQ

15KP40A-TP

Micro Commercial CoIn Stock: 107315KP40A-TP Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 3KP40 is determined by the following critical electrical and mechanical parameters:

• Voltage Rating: Reverse standoff voltage must be 40V (nominal)
• Breakdown Voltage: Minimum breakdown voltage in the range of 42.08V to 44.4V
• Clamping Voltage: Maximum clamping voltage at peak pulse current between 64.5V and 67.73V
• Package Type: Through-hole axial mounting (P600 or R-6 compatible packages)
• Diode Type: Unidirectional Zener TVS diode
• Operating Temperature: Minimum -55°C to maximum 175°C junction temperature
• RoHS Compliance: ROHS3 Compliant

Substitute parts may differ in peak pulse power rating and peak pulse current capacity while maintaining the same voltage protection characteristics and package compatibility. These differences allow for application-specific selection based on transient energy requirements.

Parameter Comparison

Engineering Selection Recommendations

5KP40A (Diotec Semiconductor): This substitute maintains identical voltage protection characteristics (40V standoff, 64.5V clamping) with increased peak pulse power rating (5000W) and higher peak pulse current (78A). The P600 axial package provides direct mechanical compatibility. Product status is active with established supply chain availability. Operating temperature minimum is -50°C, which is 5°C higher than the original specification. ROHS3 compliance is confirmed.

15KP40A-TP (Micro Commercial Co): This substitute provides the highest peak pulse power rating (15000W) while maintaining voltage protection parameters within acceptable tolerance (40V standoff, 65.8V clamping). The R-6 axial package is mechanically compatible with through-hole mounting. Product status is active. Operating temperature range (-55 to 175°C) matches the original specification. Supplied in tape and reel packaging. ROHS3 compliance and REACH unaffected status are confirmed.

Selection between substitutes depends on application transient energy requirements and packaging format preference. Both substitutes are ROHS3 compliant and suitable for general-purpose overvoltage protection applications.

Frequently Asked Questions (FAQ)

Q: Can the 5KP40A replace the 3KP40 in all applications?

A: The 5KP40A maintains the same 40V voltage rating and clamping characteristics as the 3KP40. The primary difference is increased power dissipation capability (5000W vs 3000W) and higher peak pulse current (78A vs 46.5A). The P600 axial package is mechanically identical. The operating temperature minimum is -50°C instead of -55°C. Substitution is valid for applications where the lower temperature limit is acceptable.

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

A: Both P600 and R-6 are axial through-hole packages formats for TVS diodes. The packages are mechanically compatible for through-hole PCB mounting. The R-6 package designation indicates a different physical form factor. Both support the same electrical performance and mounting methodology.

Q: Why does the 15KP40A-TP have a higher power rating?

A: The 15KP40A-TP is rated for 15000W peak pulse power dissipation compared to 3000W for the 3KP40. This higher rating reflects the component's ability to dissipate greater transient energy. The voltage protection characteristics (40V standoff, 65.8V clamping) remain within the acceptable range for substitution. Selection of higher power-rated components is appropriate for applications with greater transient energy exposure.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. The 5KP40A and 15KP40A-TP are both ROHS3 compliant, matching the compliance status of the original 3KP40.

Q: What is the significance of the -TP suffix on the 15KP40A-TP?

A: The -TP suffix indicates tape and reel packaging format, suitable for automated assembly processes. This is a packaging designation and does not affect electrical performance or substitution compatibility.