3KP24A-B Transient Voltage Suppressor - Equivalent & Substitute Parts

Part Overview

The 3KP24A-B is a unidirectional Zener transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection applications. This component features a 24V reverse standoff voltage with a 38.9V maximum clamping voltage and 77.1A peak pulse current capability in a through-hole P600 axial package. The product is currently obsolete, necessitating identification of functionally equivalent alternatives that maintain electrical and mechanical compatibility for circuit protection requirements.

Key Parameters

Parameter	Value
Voltage - Reverse Standoff (Typ)	24V
Voltage - Breakdown (Min)	26.7V
Voltage - Clamping (Max) @ Ipp	38.9V
Current - Peak Pulse (10/1000µs)	77.1A
Power - Peak Pulse	3000W (3kW)
Operating Temperature Range	-55°C ~ 175°C (TJ)
Mounting Type	Through Hole
Package / Case	P600, Axial
Type	Zener
Unidirectional Channels	1
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitute parts for the 3KP24A-B are qualified based on the following electrical and mechanical parameters:

Primary Substitution Criteria:

Voltage - Reverse Standoff: 24V (exact match required)
Voltage - Clamping (Max) @ Ipp: 38.9V (exact match required)
Voltage - Breakdown (Min): 26.7V (exact match required)
Type: Zener, Unidirectional (1 channel)
Operating Temperature Range: -55°C ~ 175°C (TJ)
Mounting Type: Through Hole
RoHS Status: ROHS3 Compliant

Secondary Considerations:

Current - Peak Pulse (10/1000µs): May vary based on application requirements
Power - Peak Pulse: May vary based on application requirements
Package / Case: Through-hole axial packages (P600, R-6, or DO-15)

Three substitute parts meet these criteria with variations in current handling capacity and package form factor.

Parameter Comparison

Parameter	3KP24A-B (Main)	5KP24A-B	3KP24A-TP	SA24A-AP
Manufacturer	Littelfuse Inc.	Littelfuse Inc.	Micro Commercial Co	Micro Commercial Co
Product Status	Obsolete	Active	Active	Active
Voltage - Reverse Standoff (Typ)	24V	24V	24V	24V
Voltage - Breakdown (Min)	26.7V	26.7V	26.7V	26.7V
Voltage - Clamping (Max) @ Ipp	38.9V	38.9V	38.9V	38.9V
Current - Peak Pulse (10/1000µs)	77.1A	131.1A	Not specified	13.1A
Power - Peak Pulse	3000W (3kW)	5000W (5kW)	3000W (3kW)	500W
Operating Temperature Range	-55°C ~ 175°C (TJ)	-55°C ~ 175°C (TJ)	-55°C ~ 175°C (TJ)	-55°C ~ 175°C (TJ)
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole
Package / Case	P600, Axial	P600, Axial	R-6, Axial	DO-204AC, DO-15, Axial
Type	Zener	Zener	Zener	Zener
Unidirectional Channels	1	1	1	1
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	Not specified

Engineering Selection Recommendations

5KP24A-B (Littelfuse Inc.): This part is the direct successor from the same manufacturer with identical electrical characteristics and package form factor. It maintains active product status and ROHS3 compliance. The increased peak pulse current (131.1A) and power rating (5kW) provide enhanced protection capability without compromising compatibility. This is the primary substitute for applications requiring the original P600 package.

3KP24A-TP (Micro Commercial Co): This part matches the electrical specifications and power rating of the original 3KP24A-B. It is manufactured by an alternative supplier and uses an R-6 axial package instead of P600. Active product status and ROHS3 compliance are maintained. This substitute is suitable for applications where package form factor variation is acceptable.

SA24A-AP (Micro Commercial Co): This part maintains identical voltage specifications and operating temperature range. However, it features significantly reduced peak pulse current (13.1A) and power dissipation (500W) compared to the original. The DO-15 package represents a different form factor. This substitute is applicable only to low-energy transient protection applications with reduced surge current requirements.

Frequently Asked Questions (FAQ)

Q: Can the 5KP24A-B directly replace the 3KP24A-B in all applications?

A: Yes, for applications requiring the original 77.1A peak pulse current or less. The 5KP24A-B provides identical voltage characteristics and package form factor with higher current and power ratings, making it a direct upgrade. No circuit modifications are required.

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

A: Both are through-hole axial packages for Zener diodes. P600 and R-6 are different mechanical form factors from different manufacturers. Physical dimensions and lead spacing may differ. Verify PCB footprint compatibility before substitution.

Q: Is the SA24A-AP suitable as a general replacement?

A: The SA24A-AP is suitable only for applications with low transient energy requirements. Its 13.1A peak pulse current and 500W power rating are significantly lower than the original 3KP24A-B. Use this substitute only when application surge current specifications are confirmed to be below 13.1A.

Q: Are all substitute parts RoHS compliant?

A: The 5KP24A-B and 3KP24A-TP are confirmed ROHS3 compliant. RoHS status for SA24A-AP is not specified in available documentation.

Q: What is the impact of using a higher-rated part like the 5KP24A-B?

A: Using a higher-rated TVS diode provides improved protection margin without negative effects. The identical voltage characteristics ensure proper circuit operation, while the increased current and power ratings offer enhanced transient suppression capability.

Q: Can these parts be used interchangeably in PCB designs?

A: Electrical interchangeability is confirmed for all three substitutes based on voltage specifications. Mechanical interchangeability depends on package form factor. Verify PCB footprint compatibility for the selected package type (P600, R-6, or DO-15) before implementation.

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