P4KE51 Equivalent & Substitute Parts

Part Overview

The P4KE51 is a unidirectional transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection applications. This component features a 43.6V reverse standoff voltage, 73.61V maximum clamping voltage, and 400W peak pulse power rating in a through-hole DO-204AL (DO-41) axial package. The P4KE51 is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

Key Parameters

Parameter	Value
Voltage - Reverse Standoff (Typ)	43.6V
Voltage - Breakdown (Min)	45.95V
Voltage - Clamping (Max) @ Ipp	73.61V
Current - Peak Pulse (10/1000µs)	5.8A
Power - Peak Pulse	400W
Type	Zener
Unidirectional Channels	1
Mounting Type	Through Hole
Package / Case	DO-204AL, DO-41, Axial
Operating Temperature	-55°C ~ 175°C (TJ)
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution of the P4KE51 is determined by the following critical electrical and mechanical parameters:

Voltage - Reverse Standoff (Typ): 43.6V
Voltage - Clamping (Max) @ Ipp: 70.1V to 73.61V
Current - Peak Pulse (10/1000µs): 5.7A to 6.0A
Power - Peak Pulse: 400W
Package / Case: DO-204AL or DO-15 axial through-hole
Type: Unidirectional Zener TVS Diode
Operating Temperature Range: -55°C to 175°C minimum

Substitute parts must maintain electrical compatibility within these parameters. Variations in clamping voltage (70.1V vs. 73.61V) and peak pulse current (5.7A to 6.0A) remain within acceptable tolerance for general-purpose transient suppression applications. Package variants (DO-204AL, DO-15) are mechanically and electrically interchangeable in through-hole mounting configurations.

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff (Typ)	Voltage - Clamping (Max) @ Ipp	Current - Peak Pulse (10/1000µs)	Power - Peak Pulse	Package / Case	Operating Temperature	Product Status
P4KE51	Littelfuse Inc.	43.6V	73.61V	5.8A	400W	DO-204AL, DO-41	-55°C ~ 175°C	Obsolete
P4KE51A	Diotec Semiconductor	43.6V	70.1V	6A	400W	DO-204AC, DO-15	-50°C ~ 175°C	Active
BZW04-44-E3/54	Vishay General Semiconductor	43.6V	70.1V	5.7A	400W	DO-204AL, DO-41	-55°C ~ 175°C	Active
P4KE51A-E3/54	Vishay General Semiconductor	43.6V	70.1V	5.7A	400W	DO-204AL, DO-41	-55°C ~ 175°C	Active
P4KE51AHE3/54	Vishay General Semiconductor	43.6V	70.1V	5.7A	400W	DO-204AL, DO-41	-55°C ~ 175°C	Active
P4KE51A-AP	Micro Commercial Co	43.6V	70.1V	5.8A	400W	DO-204AL, DO-41	-55°C ~ 175°C	Active
P4KE51A-BP	Micro Commercial Co	43.6V	70.1V	5.8A	400W	DO-204AL, DO-41	-55°C ~ 175°C	Active
P4KE51A-G	Comchip Technology	43.6V	70.1V	5.71A	400W	DO-204AL, DO-41	-55°C ~ 150°C	Active
P4KE51A-TP	Micro Commercial Co	43.6V	70.1V	5.8A	400W	DO-204AL, DO-41	-55°C ~ 175°C	Active
P6KE51A	Fairchild Semiconductor	43.6V	Not specified	Not specified	Not specified	Not specified	Not specified	Active

Engineering Selection Recommendations

All listed substitute parts maintain active product status except the original P4KE51, which is obsolete. Selection among substitutes should prioritize the following criteria:

RoHS3 Compliance: BZW04-44-E3/54, P4KE51A-E3/54, P4KE51AHE3/54, and P4KE51A-G are explicitly ROHS3 compliant. P4KE51A from Diotec Semiconductor does not specify RoHS status.

Automotive Qualification: P4KE51AHE3/54 carries AEC-Q101 qualification and is designated for automotive applications, providing additional reliability assurance for mission-critical environments.

Operating Temperature Range: P4KE51A-G operates to 150°C maximum junction temperature, which is 25°C lower than other substitutes. Applications requiring full -55°C to 175°C operation should avoid this variant.

Package Availability: BZW04-44-E3/54 and Vishay variants are supplied in Tape & Reel (TR) or Cut Tape (CT) packaging. Micro Commercial Co variants offer Tape & Box (TB) and Bulk options. Diotec P4KE51A is available in standard packaging.

Electrical Tolerance: All substitutes maintain 43.6V reverse standoff voltage. Clamping voltage ranges from 70.1V to 73.61V, with peak pulse current between 5.7A and 6.0A. These variations fall within acceptable design margins for general-purpose transient suppression.

Frequently Asked Questions (FAQ)

Q: Can P4KE51A from Diotec replace the obsolete P4KE51 from Littelfuse?

A: Yes. Both parts share identical reverse standoff voltage (43.6V), equivalent clamping voltage (70.1V vs. 73.61V), and 400W power rating. The primary difference is operating temperature minimum: P4KE51A operates from -50°C, while P4KE51 operates from -55°C. For applications within -50°C to 175°C, direct substitution is valid.

Q: What is the difference between BZW04-44-E3/54 and P4KE51A-E3/54?

A: Both are manufactured by Vishay General Semiconductor and share identical electrical specifications (43.6V standoff, 70.1V clamping, 5.7A peak pulse, 400W power). BZW04-44-E3/54 is part of the TransZorb® series, while P4KE51A-E3/54 uses the P4KE base designation. Packaging and availability may differ; both are ROHS3 compliant and suitable for direct substitution.

Q: Is P4KE51AHE3/54 suitable for automotive applications?

A: Yes. P4KE51AHE3/54 carries AEC-Q101 qualification and is explicitly designated for automotive grade applications. It maintains full electrical compatibility with the P4KE51 and is supplied in Cut Tape (CT) packaging.

Q: What packaging options are available for P4KE51 substitutes?

A: Substitute parts are available in multiple packaging formats: Tape & Reel (TR) for high-volume automated assembly, Cut Tape (CT) for mixed-volume applications, Tape & Box (TB) for moderate quantities, and Bulk for manual assembly. All maintain DO-204AL or DO-15 axial through-hole package compatibility.

Q: Can P4KE51A-G be used in applications requiring -55°C operation?

A: No. P4KE51A-G from Comchip Technology operates from -55°C to 150°C maximum junction temperature. Applications requiring full -55°C to 175°C operation must use alternative substitutes such as BZW04-44-E3/54, P4KE51A-E3/54, P4KE51A-AP, P4KE51A-BP, or P4KE51A-TP.

Q: Are all substitutes ROHS3 compliant?

A: No. ROHS3 compliance is confirmed for BZW04-44-E3/54, P4KE51A-E3/54, P4KE51AHE3/54, and P4KE51A-G. P4KE51A from Diotec Semiconductor does not specify RoHS status. Micro Commercial Co variants (P4KE51A-AP, P4KE51A-BP, P4KE51A-TP) do not specify RoHS status in provided documentation.

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