Equivalent & Substitute Parts for 5KP43C-B

Part Overview

The 5KP43C-B is a bidirectional transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection applications. Featuring a 43V reverse standoff voltage and 5000W peak pulse power rating in a P600 axial through-hole package, this component provides robust transient suppression across a wide operating temperature range of -55°C to 175°C.

The 5KP43C-B is classified as obsolete. Equivalent and substitute parts are necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements. Substitute selection must account for electrical performance parameters, package compatibility, and application requirements.

Key Parameters

Parameter	5KP43C-B Value	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
Bidirectional Channels	1	—
Type	Zener	—
Package / Case	P600, Axial	—
Operating Temperature	-55 to 175	°C
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution logic for the 5KP43C-B is based on the following critical parameters:

Primary Substitutes (Direct Equivalents):

Voltage - Reverse Standoff: 43V nominal
Package / Case: P600, Axial (same form factor and pin configuration)
Power - Peak Pulse: 5000W (same power dissipation capability)
Bidirectional operation with single channel
Operating temperature range: -55°C to 175°C minimum

Secondary Substitutes (Functional Alternatives):

Voltage - Reverse Standoff: 40.2V to 48V (within acceptable operating margin)
Package / Case: DO-201AA or DO-15 (alternative through-hole packages)
Power - Peak Pulse: 1500W to 600W (reduced power handling for lower-stress applications)
Bidirectional operation with single channel
Operating temperature range: -50°C to 175°C minimum

Substitutes are grouped by package type and power rating to ensure mechanical fit and electrical performance compatibility with the original design.

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff (V)	Voltage - Clamping (Max) @ Ipp (V)	Power - Peak Pulse (W)	Package / Case	Product Status
5KP43C-B	Littelfuse Inc.	43	72.87	5000	P600, Axial	Obsolete
5KP43CA	Littelfuse Inc.	43	69.4	5000	P600, Axial	Active
5KP43CA-B	Littelfuse Inc.	43	69.4	5000	P600, Axial	Active
SLD43-018-B	Littelfuse Inc.	43	69.4	5000	P600, Axial	Active
1.5KE47CA	Diotec Semiconductor	40.2	64.8	1500	DO-201AA, Axial	Active
1.5KE51CA	Taiwan Semiconductor Corporation	43.6	70.1	1500	DO-201AA, Axial	Active
1.5KE56CA	Taiwan Semiconductor Corporation	47.8	77	1500	DO-201AA, Axial	Active
P6KE47CA	Diotec Semiconductor	40.2	64.8	600	DO-204AC, Axial	Active
P6KE51CA	Taiwan Semiconductor Corporation	43.6	70.1	600	DO-204AC, Axial	Active
SA48CA	Taiwan Semiconductor Corporation	48	77.4	500	DO-204AC, Axial	Active
1N6124	Semtech Corporation	42.6	80.7	500	Axial	Discontinued

Engineering Selection Recommendations

Tier 1 - Direct Replacement (Recommended):

5KP43CA, 5KP43CA-B, and SLD43-018-B are the primary substitutes for the 5KP43C-B. All three maintain identical voltage ratings (43V reverse standoff), package form factor (P600 axial), and power dissipation (5000W). These parts are manufactured by Littelfuse Inc. and are in active production status. 5KP43CA-B and SLD43-018-B carry ROHS3 compliance and REACH Unaffected status, ensuring regulatory alignment with modern supply chain requirements.

Tier 2 - Functional Alternatives (Package Change Required):

1.5KE51CA and 1.5KE56CA provide voltage ratings within acceptable operating margins (43.6V and 47.8V respectively) but require mechanical redesign due to DO-201AA package substitution. These parts maintain 1500W peak pulse power and are suitable for applications where reduced power dissipation is acceptable. Both are ROHS3 compliant and in active production.

Tier 3 - Lower Power Alternatives (Design Modification Required):

P6KE51CA and P6KE47CA offer voltage compatibility but operate at 600W peak pulse power, requiring significant circuit redesign. These parts use DO-204AC (DO-15) packages and are suitable only for low-stress transient suppression applications. Both are ROHS3 compliant and in active production.

Not Recommended:

1N6124 is discontinued at DiGi Electronics and should not be selected for new designs. SA48CA operates at 500W power rating and 48V standoff voltage, introducing both mechanical and electrical incompatibility.

Frequently Asked Questions (FAQ)

Q: Can 5KP43CA directly replace 5KP43C-B without circuit modification?

A: Yes. 5KP43CA maintains identical voltage ratings (43V reverse standoff), clamping voltage (69.4V), power dissipation (5000W), and P600 axial package configuration. No circuit redesign is required. The primary difference is product status: 5KP43C-B is obsolete while 5KP43CA is in active production.

Q: What is the difference between 5KP43CA and 5KP43CA-B?

A: Both parts share identical electrical specifications and P600 package. The primary difference is packaging format: 5KP43CA is supplied in Cut Tape (CT), while 5KP43CA-B is supplied in Bulk. Selection depends on procurement and assembly requirements.

Q: Can 1.5KE51CA replace 5KP43C-B in my application?

A: 1.5KE51CA provides compatible voltage ratings (43.6V reverse standoff, 70.1V clamping) but operates at 1500W peak pulse power versus 5000W for the original part. This substitution requires circuit evaluation to confirm that reduced power dissipation capacity is acceptable. Additionally, the DO-201AA package differs from the P600 package, requiring mechanical redesign of the PCB layout.

Q: Why is 1N6124 not recommended as a substitute?

A: 1N6124 is discontinued at DiGi Electronics and carries discontinued product status. Additionally, it operates at 500W peak pulse power and 42.6V reverse standoff voltage, both of which deviate from the original 5KP43C-B specifications. New designs should not incorporate discontinued components.

Q: What are the key parameters I must verify when selecting a substitute?

A: Verify reverse standoff voltage (43V nominal), clamping voltage (within 69.4V to 72.87V range), peak pulse power (5000W for direct replacement), package type (P600 axial for mechanical compatibility), and operating temperature range (-55°C to 175°C minimum). Product status and compliance certifications (ROHS3, REACH) should also be confirmed for supply chain continuity.

Q: Can I use P6KE51CA in place of 5KP43C-B?

A: P6KE51CA provides compatible voltage ratings (43.6V reverse standoff, 70.1V clamping) but operates at 600W peak pulse power, significantly lower than the 5000W rating of the original part. This substitution is suitable only for low-stress applications and requires thorough circuit analysis. The DO-204AC (DO-15) package also differs from P600, necessitating PCB layout modification.

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