5KP51C-B Equivalent & Substitute Parts

Part Overview

The 5KP51C-B is a bidirectional transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection applications. This component features a 51V reverse standoff voltage, 86.52V maximum clamping voltage, and 5000W peak pulse power rating in a through-hole P600 axial package. The product is currently obsolete, necessitating identification of active equivalent and substitute parts that maintain functional compatibility for circuit protection requirements.

Key Parameters

Parameter	5KP51C-B
Manufacturer	Littelfuse Inc.
Type	Zener TVS Diode
Bidirectional Channels	1
Voltage - Reverse Standoff (Typ)	51V
Voltage - Breakdown (Min)	53.73V
Voltage - Clamping (Max) @ Ipp	86.52V
Power - Peak Pulse	5000W (5kW)
Operating Temperature	-55°C ~ 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 5KP51C-B is determined by the following critical parameters:

Voltage Rating: Reverse standoff voltage of 51V with breakdown minimum of 53.73V
Clamping Voltage: Maximum clamping voltage at peak pulse current (Ipp)
Power Dissipation: 5000W peak pulse power rating
Package Type: Through-hole axial configuration (P600 or compatible)
Bidirectionality: Single bidirectional channel for AC/DC protection
Temperature Range: Operating range of -55°C to 175°C
Compliance: ROHS3 compliance and active product status

Substitute parts are grouped into two categories:

Category A - Direct Equivalents (P600 Package, 5000W Rating): Parts maintaining identical package, power rating, and voltage specifications with active product status.

Category B - Functional Alternatives (Alternative Packages, Lower Power Ratings): Parts with compatible voltage ratings but different package types or reduced power dissipation, suitable for applications with lower current requirements.

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff	Voltage - Breakdown (Min)	Voltage - Clamping (Max)	Current - Peak Pulse	Power - Peak Pulse	Package / Case	Product Status	RoHS Status
5KP51C-B	Littelfuse Inc.	51V	53.73V	86.52V	-	5000W	P600, Axial	Obsolete	ROHS3
5KP51CA	Littelfuse Inc.	51V	56.7V	82.4V	61.9A	5000W	P600, Axial	Active	ROHS3
5KP51CA-B	Littelfuse	51V	56.7V	82.4V	61.9A	5000W	P600, Axial	Active	ROHS3
5KP51CE3/TR13	Microchip Technology	51V	56.7V	91.1V	54.9A	5000W	P600, Axial	Active	ROHS3
5KP51CA-TP	Micro Commercial Co	51V	56.7V	82.4V	-	5000W	R-6, Axial	Active	ROHS3
1.5KE62CA	Taiwan Semiconductor Corporation	53V	58.9V	85V	18A	1500W	DO-201AA, Axial	Active	ROHS3
1.5KE68CA	Taiwan Semiconductor Corporation	58.1V	64.6V	92V	17A	1500W	DO-201AA, Axial	Active	ROHS3
P6KE62CA	Diotec Semiconductor	53V	58.9V	85V	7.4A	600W	DO-15, Axial	Active	ROHS3
P6KE68CA	Fairchild Semiconductor	58.1V	64.6V	92V	6.8A	600W	DO-15, Axial	Active	-
P4KE62CA-TP	Micro Commercial Co	53V	58.9V	85V	4.8A	400W	DO-41, Axial	Active	-

Engineering Selection Recommendations

Primary Substitutes (Recommended for Direct Replacement)

The 5KP51CA and 5KP51CA-B are the preferred direct substitutes for the obsolete 5KP51C-B. Both parts maintain the identical 51V reverse standoff voltage, P600 axial package configuration, and 5000W peak pulse power rating. These components are manufactured by Littelfuse Inc. with active product status and ROHS3 compliance. The 5KP51CA-B is available in bulk packaging with 686 units in stock, while 5KP51CA is supplied in cut tape format with 3400 units available.

The 5KP51CE3/TR13 from Microchip Technology provides an alternative with identical voltage and power specifications in the P600 package. This part features a higher clamping voltage of 91.1V compared to the original 86.52V specification, with active product status and ROHS3 compliance.

Secondary Substitutes (Alternative Package Configurations)

The 5KP51CA-TP from Micro Commercial Co maintains the 51V voltage rating and 5000W power dissipation but uses an R-6 axial package instead of P600. This part is suitable for applications where package footprint differences are acceptable.

Lower Power Alternatives (Reduced Current Applications)

For applications with reduced peak pulse current requirements, the 1.5KE62CA and 1.5KE68CA from Taiwan Semiconductor Corporation provide 1500W power ratings in DO-201AA packages. The 1.5KE62CA maintains a 53V standoff voltage with 85V clamping, while 1.5KE68CA offers 58.1V standoff with 92V clamping. Both are ROHS3 compliant with active product status.

The P6KE62CA and P6KE68CA series offer 600W power ratings in DO-15 packages for low-current protection circuits. P6KE62CA provides 53V standoff voltage with 85V clamping, while P6KE68CA delivers 58.1V standoff with 92V clamping.

The P4KE62CA-TP provides the lowest power option at 400W in a DO-41 package, suitable for minimal current transient suppression with 53V standoff voltage and 85V clamping.

Frequently Asked Questions (FAQ)

Q: Can 5KP51CA directly replace 5KP51C-B without circuit modification?

A: Yes. The 5KP51CA maintains identical voltage ratings (51V standoff), package type (P600 axial), and power dissipation (5000W). Both are bidirectional single-channel TVS diodes with compatible operating temperature ranges (-55°C to 175°C). No circuit modifications are required.

Q: What is the difference between 5KP51CA and 5KP51CA-B?

A: Both parts are electrically identical with 51V standoff voltage, 82.4V clamping voltage, and 5000W power rating in P600 packages. The primary difference is packaging format: 5KP51CA is supplied in cut tape, while 5KP51CA-B is supplied in bulk. Selection depends on procurement and assembly requirements.

Q: Why do some substitutes have different clamping voltages?

A: Clamping voltage varies based on the peak pulse current (Ipp) at which it is measured. The 5KP51CE3/TR13 exhibits 91.1V clamping compared to the original 86.52V due to different internal design characteristics. Both maintain the same 51V standoff voltage and 5000W power rating, making them functionally equivalent for circuit protection.

Q: Can I use 1.5KE62CA or P6KE62CA as substitutes?

A: These parts are functional alternatives only if your circuit can tolerate reduced power dissipation. The 1.5KE62CA provides 1500W (versus 5000W) and the P6KE62CA provides 600W. Use these only when peak pulse current requirements are confirmed to be within their rated limits. Package types differ (DO-201AA and DO-15 respectively), requiring PCB layout verification.

Q: What does the package designation mean?

A: P600 is a through-hole axial package with specific lead spacing. R-6, DO-201AA, DO-15, and DO-41 are alternative through-hole axial packages with different physical dimensions. Substitution between package types requires PCB footprint compatibility verification.

Q: Are all substitute parts ROHS3 compliant?

A: Most substitutes listed are ROHS3 compliant. The P6KE68CA and P4KE62CA-TP do not specify RoHS status in the provided data. Verify compliance requirements with your procurement specifications before selection.

Q: What is the significance of the "-TP" suffix in part numbers?

A: The "-TP" suffix typically indicates a specific packaging or tape format variant. For example, 5KP51CA-TP uses R-6 package in cut tape format, while 5KP51CA-B uses P600 package in bulk format. Verify exact packaging specifications with the manufacturer datasheet.

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