5KP43-B Transient Voltage Suppressor (TVS) Diode - Equivalent & Substitute Parts

Part Overview

The 5KP43-B is a unidirectional Zener-type transient voltage suppressor manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection applications. This through-hole P600 axial package component features a 43V reverse standoff voltage with 5000W peak pulse power handling capability and operates across the -55°C to 175°C temperature range. The 5KP43-B is classified as obsolete, necessitating identification of active equivalent and substitute components that maintain functional compatibility within the specified electrical and mechanical parameters.

Key Parameters

Parameter	5KP43-B	Unit
Voltage - Reverse Standoff (Typ)	43	V
Voltage - Breakdown (Min)	45.27	V
Voltage - Clamping (Max) @ Ipp	72.87	V
Power - Peak Pulse	5000	W
Operating Temperature	-55 to 175	°C (TJ)
Mounting Type	Through Hole	-
Package / Case	P600, Axial	-
Type	Zener	-
Unidirectional Channels	1	-
RoHS Status	ROHS3 Compliant	-

Substitute Part Grouping Explanation

Substitution eligibility for the 5KP43-B is determined by the following critical parameters:

Primary Substitution Criteria:

Voltage - Reverse Standoff (Typ): 43V
Power - Peak Pulse: 5000W (5kW)
Mounting Type: Through Hole
Package / Case: P600, Axial
Type: Zener
Unidirectional Channels: 1
Operating Temperature Range: -55°C to 175°C (TJ)

Secondary Compatibility Parameters:

Voltage - Breakdown (Min): 45.27V to 47.8V range
Voltage - Clamping (Max) @ Ipp: 64.8V to 76.7V range
RoHS Status: ROHS3 Compliant

Substitute parts are grouped into two categories: direct equivalents maintaining identical P600 package specifications, and functional alternatives with different package configurations (DO-201, DO-15) that provide equivalent electrical protection characteristics within the specified voltage and power parameters.

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff (Typ)	Voltage - Breakdown (Min)	Voltage - Clamping (Max) @ Ipp	Power - Peak Pulse	Package / Case	Product Status	RoHS Status
5KP43-B	Littelfuse Inc.	43V	45.27V	72.87V	5000W	P600, Axial	Obsolete	ROHS3 Compliant
5KP43A-B	Littelfuse Inc.	43V	47.8V	69.4V	5000W	P600, Axial	Active	ROHS3 Compliant
5KP43A	Littelfuse Inc.	43V	47.8V	69.4V	5000W	P600, Axial	Active	ROHS3 Compliant
SLD43U-017-B	Littelfuse Inc.	43V	49V	69.4V	5000W	P600, Axial	Active	ROHS3 Compliant
5KP43E3/TR13	Microchip Technology	43V	47.8V	76.7V	5000W	P600, Axial	Active	ROHS3 Compliant
1.5KE47A	Taiwan Semiconductor Corporation	40.2V	44.7V	64.8V	1500W	DO-201AA, Axial	Active	ROHS3 Compliant
1.5KE51A	Meritek	-	48.5V	70.1V	1500W	DO-201, Axial	Active	-
SA40A-TP	Micro Commercial Co	40V	44.4V	64.5V	500W	DO-15, Axial	Active	-
P6KE51A	Fairchild Semiconductor	-	-	-	-	-	Active	-
P6KE56A-TP	Micro Commercial Co	47.8V	53.2V	77V	600W	DO-15, Axial	Active	-

Engineering Selection Recommendations

Direct P600 Package Equivalents (Recommended Primary Substitutes):

The 5KP43A-B and 5KP43A from Littelfuse Inc. are the primary recommended substitutes, maintaining identical P600 axial package specifications, 43V reverse standoff voltage, and 5000W peak pulse power rating. Both components are active products with ROHS3 compliance. The 5KP43A-B is available in bulk packaging with 686 units in stock, while 5KP43A is available in cut tape with 3339 units in stock.

The SLD43U-017-B from Littelfuse Inc. provides an automotive-grade alternative (AEC-Q101 qualified) in the same P600 package with identical electrical specifications, suitable for applications requiring automotive qualification. This component is active with 995 units in stock.

The 5KP43E3/TR13 from Microchip Technology maintains the P600 package and 5000W power rating with a 43V reverse standoff voltage. This active component offers a higher clamping voltage (76.7V) compared to the original 5KP43-B (72.87V) and is available in tape and reel packaging with 1076 units in stock.

Alternative Package Solutions (Lower Power Density):

The 1.5KE47A from Taiwan Semiconductor Corporation and 1.5KE51A from Meritek provide functional alternatives in DO-201 axial packages with reduced power handling (1500W versus 5000W). These components operate within the specified temperature range and maintain ROHS3 compliance. The 1.5KE47A is available with 36829 units in stock.

Lower Power Applications:

The SA40A-TP from Micro Commercial Co in DO-15 package provides a 500W alternative for applications with reduced transient energy requirements. This component maintains the -55°C to 175°C operating temperature range and is available with 799 units in stock.

Frequently Asked Questions (FAQ)

Q: Can I directly replace 5KP43-B with 5KP43A-B?

A: Yes. Both components share identical P600 axial package specifications, 43V reverse standoff voltage, and 5000W peak pulse power rating. The 5KP43A-B is an active product with ROHS3 compliance, making it a direct functional equivalent for the obsolete 5KP43-B.

Q: What is the difference between 5KP43A and 5KP43A-B?

A: Both components are electrically identical with 43V reverse standoff voltage and 5000W power rating in P600 packages. The primary difference is packaging format: 5KP43A is supplied in cut tape, while 5KP43A-B is supplied in bulk. Selection depends on procurement and assembly requirements.

Q: Can I use 1.5KE47A as a substitute for 5KP43-B?

A: The 1.5KE47A provides electrical compatibility within the voltage parameters (40.2V reverse standoff, 44.7V breakdown minimum, 64.8V clamping maximum) and operates across the same temperature range. However, the power handling is reduced to 1500W versus 5000W, and the package changes from P600 to DO-201 axial. This substitute is suitable only for applications where 1500W peak pulse power is sufficient and the DO-201 package is mechanically compatible.

Q: Is SLD43U-017-B suitable for automotive applications?

A: Yes. The SLD43U-017-B is AEC-Q101 qualified and carries automotive-grade designation. It maintains identical electrical specifications to the 5KP43-B (43V reverse standoff, 5000W power, P600 package) and is suitable for automotive transient voltage suppression applications.

Q: What are the package compatibility considerations?

A: The 5KP43-B uses a P600 axial through-hole package. Direct substitutes (5KP43A-B, 5KP43A, SLD43U-017-B, 5KP43E3/TR13) maintain this package specification and require no PCB layout modifications. Alternative packages (1.5KE47A in DO-201, SA40A-TP in DO-15) require different PCB footprints and may not be pin-compatible without circuit board redesign.

Q: Why is the clamping voltage different between 5KP43-B (72.87V) and 5KP43A-B (69.4V)?

A: Both components maintain the same 43V reverse standoff voltage and 5000W power rating. The clamping voltage variation (72.87V versus 69.4V) reflects manufacturing tolerance differences within the same product family. Both values fall within acceptable ranges for general-purpose transient voltage suppression and do not affect functional compatibility for standard applications.

Q: Can I use P6KE51A as a substitute?

A: Insufficient technical data is provided for P6KE51A to establish definitive substitution compatibility. While listed as an active Fairchild Semiconductor product, critical parameters including voltage ratings, power specifications, and package details are not available in the provided documentation. Detailed datasheet review is required before selection.

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