5KP40-B Transient Voltage Suppressor (TVS) Diode - Equivalent & Substitute Parts

Part Overview

The 5KP40-B is a unidirectional transient voltage suppressor 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 5000W peak pulse power rating in a through-hole P600 axial package. The part is classified as obsolete, necessitating identification of active equivalent and substitute components that maintain electrical and mechanical compatibility for ongoing system support and new designs.

Key Parameters

Parameter	5KP40-B
Manufacturer	Littelfuse Inc.
Type	Zener TVS Diode
Unidirectional Channels	1
Voltage - Reverse Standoff (Typ)	40V
Voltage - Breakdown (Min)	42.08V
Voltage - Clamping (Max) @ Ipp	67.73V
Power - Peak Pulse	5000W (5kW)
Operating Temperature Range	-55°C to 175°C (TJ)
Mounting Type	Through Hole
Package / Case	P600, Axial
RoHS Status	ROHS3 Compliant
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution of the 5KP40-B is determined by the following critical electrical and mechanical parameters:

Electrical Compatibility Criteria:

Voltage - Reverse Standoff (Typ): 40V ±tolerance
Voltage - Breakdown (Min): 42.08V to 44.7V range
Voltage - Clamping (Max) @ Ipp: 64.5V to 71.4V range
Power - Peak Pulse: 5000W minimum (5kW class)
Unidirectional configuration (single channel)
Operating Temperature: -55°C to 175°C minimum

Mechanical Compatibility Criteria:

Mounting Type: Through Hole
Package / Case: P600 axial or equivalent axial packages (R-6, DO-201)
RoHS3 Compliance

Substitute parts are grouped into two categories: direct electrical equivalents with identical package specifications (P600 axial) and functional equivalents with alternative axial packages that maintain electrical performance within specified parameters.

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff (Typ)	Voltage - Breakdown (Min)	Voltage - Clamping (Max) @ Ipp	Current - Peak Pulse (10/1000µs)	Power - Peak Pulse	Package / Case	Operating Temperature	Product Status	RoHS Status
5KP40-B	Littelfuse Inc.	40V	42.08V	67.73V	—	5000W	P600, Axial	-55°C to 175°C	Obsolete	ROHS3 Compliant
5KP40A	Diotec Semiconductor	40V	44.4V	64.5V	78A	5000W	P600, Axial	-50°C to 175°C	Active	ROHS3 Compliant
5KP40A-B	Littelfuse Inc.	40V	44.4V	64.5V	79.1A	5000W	P600, Axial	-55°C to 175°C	Active	ROHS3 Compliant
1.5KE47A	Taiwan Semiconductor Corporation	40.2V	44.7V	64.8V	24A	1500W	DO-201AA, Axial	-55°C to 175°C	Active	ROHS3 Compliant
SLD40U-017-B	Littelfuse Inc.	40V	44.4V	64.5V	79.1A	5000W	P600, Axial	-55°C to 175°C	Active	ROHS3 Compliant
15KP40A-TP	Micro Commercial Co	40V	44.4V	65.8V	—	15000W	R-6, Axial	-55°C to 175°C	Active	ROHS3 Compliant
5KP40E3/TR13	Microchip Technology	40V	44.4V	71.4V	70A	5000W	P600, Axial	-55°C to 175°C	Active	ROHS3 Compliant
SA40A-TP	Micro Commercial Co	40V	44.4V	64.5V	7.9A	500W	DO-15, Axial	-55°C to 175°C	Active	Not specified

Engineering Selection Recommendations

Primary Substitutes (Recommended for Direct Replacement):

5KP40A-B (Littelfuse Inc.) and SLD40U-017-B (Littelfuse Inc.) are the preferred substitutes. Both maintain identical electrical specifications (40V standoff, 64.5V clamping, 5000W peak pulse), P600 axial package compatibility, and -55°C to 175°C operating temperature range. SLD40U-017-B includes AEC-Q101 automotive qualification, suitable for applications requiring automotive-grade components. Both are active products with ROHS3 compliance.

5KP40A (Diotec Semiconductor) provides equivalent electrical performance in the P600 package with 5000W power rating. The operating temperature minimum is -50°C, which may be limiting for applications requiring full -55°C operation.

Secondary Substitutes (Functional Equivalents with Package Variations):

5KP40E3/TR13 (Microchip Technology) maintains P600 axial package compatibility with identical electrical parameters except for a higher clamping voltage of 71.4V, within acceptable tolerance for 40V standoff applications.

15KP40A-TP (Micro Commercial Co) provides higher power dissipation capability (15000W) in an R-6 axial package. This substitute is suitable for applications where increased thermal margin is beneficial, though package dimensions differ from P600.

1.5KE47A (Taiwan Semiconductor Corporation) operates at reduced power rating (1500W) in a DO-201 axial package. This substitute is appropriate only for lower-power applications where the 5000W rating is not required.

Not Recommended for Direct Substitution:

SA40A-TP (Micro Commercial Co) has insufficient power rating (500W) for applications requiring 5000W peak pulse capability and is unsuitable as a general replacement.

P6KE51A (Fairchild Semiconductor) lacks sufficient technical specification data for reliable substitution assessment.

P6KE56A-TP (Micro Commercial Co) operates at 47.8V standoff voltage, outside the 40V specification range, and is not suitable for this application.

Frequently Asked Questions (FAQ)

Q: Can 5KP40A-B be used as a direct replacement for 5KP40-B?

A: Yes. Both components share identical reverse standoff voltage (40V), equivalent clamping voltage (64.5V vs. 67.73V), matching 5000W power rating, P600 axial package, and -55°C to 175°C operating temperature range. 5KP40A-B is an active product from the same manufacturer.

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

A: Both are through-hole axial packages for TVS diodes. P600 and R-6 differ in physical dimensions and lead spacing. Mechanical compatibility with PCB footprints must be verified before substitution. 15KP40A-TP in R-6 package requires confirmation that the target PCB accommodates R-6 lead spacing.

Q: Why does 1.5KE47A have lower power rating than 5KP40-B?

A: The 1.5KE47A is rated for 1500W peak pulse versus 5000W for 5KP40-B. This reflects different thermal design and package capability. 1.5KE47A is suitable only for applications where peak pulse power does not exceed 1500W.

Q: Is SLD40U-017-B suitable for automotive applications?

A: Yes. SLD40U-017-B carries AEC-Q101 automotive qualification and ROHS3 compliance, making it appropriate for automotive-grade circuit protection requirements.

Q: What does "Voltage - Clamping (Max) @ Ipp" mean in substitution context?

A: This parameter specifies the maximum voltage across the TVS diode when peak pulse current flows through it. Substitutes must maintain clamping voltage within the range 64.5V to 71.4V to ensure adequate overvoltage suppression without exceeding downstream component voltage ratings.

Q: Can I use 5KP40E3/TR13 if my application requires -55°C minimum operating temperature?

A: Yes. 5KP40E3/TR13 operates across -55°C to 175°C, meeting the full temperature range requirement. The higher clamping voltage (71.4V) remains within acceptable tolerance for 40V standoff applications.

Q: Why is P6KE51A not recommended?

A: Insufficient technical specification data is provided for P6KE51A to confirm electrical parameter compatibility with 5KP40-B. Substitution decisions require complete voltage, current, and power specifications.

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