P4KE51C Equivalent & Substitute Parts

Part Overview

The P4KE51C is a bidirectional transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection in through-hole applications. This part operates with a reverse standoff voltage of 43.6V and peak pulse power rating of 400W in a DO-204AL (DO-41) axial package. The P4KE51C 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
Bidirectional Channels	1
Mounting Type	Through Hole
Package / Case	DO-204AL, DO-41, Axial
Operating Temperature	-55°C ~ 175°C (TJ)
RoHS Status	ROHS3 Compliant
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution for the P4KE51C is determined by the following critical parameters:

Voltage - Reverse Standoff (Typ): 43.6V (primary selection criterion)
Voltage - Clamping (Max) @ Ipp: Must remain within acceptable range for circuit protection
Current - Peak Pulse (10/1000µs): Minimum 5.8A required
Power - Peak Pulse: 400W minimum
Package / Case: DO-204AL (DO-41) axial through-hole configuration
Type: Zener bidirectional TVS diode
Operating Temperature Range: -55°C to 175°C minimum

Substitute parts are grouped into two categories:

Category A - Direct Electrical Equivalents (Same Standoff Voltage, Same Package) Parts with 43.6V reverse standoff voltage in DO-204AL (DO-41) package, maintaining identical electrical performance envelope.

Category B - Manufacturer Recommended Alternatives (Higher Performance) Parts with 43.6V reverse standoff voltage but enhanced specifications (higher current rating or power dissipation) in compatible packages.

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff (Typ)	Voltage - Clamping (Max) @ Ipp	Current - Peak Pulse (10/1000µs)	Power - Peak Pulse	Package	Product Status
P4KE51C	Littelfuse Inc.	43.6V	73.61V	5.8A	400W	DO-204AL (DO-41)	Obsolete
P4KE51CA	Taiwan Semiconductor Corporation	43.6V	70.1V	6A	400W	DO-204AL (DO-41)	Active
P6KE51CA	Taiwan Semiconductor Corporation	43.6V	70.1V	8.6A	600W	DO-204AC (DO-15)	Active
BZW04-44B-E3/54	Vishay General Semiconductor - Diodes Division	43.6V	70.1V	5.7A	400W	DO-204AL (DO-41)	Active
P4KE51CA-E3/54	Vishay General Semiconductor - Diodes Division	43.6V	70.1V	5.7A	400W	DO-204AL (DO-41)	Active
P4KE51CAHE3/54	Vishay General Semiconductor - Diodes Division	43.6V	70.1V	5.7A	400W	DO-204AL (DO-41)	Active
BZW04-48B	Taiwan Semiconductor Corporation	47.8V	77V	5.2A	400W	DO-204AL (DO-41)	Active
P4KE51CA-AP	Micro Commercial Co	43.6V	70.1V	5.8A	400W	DO-204AL (DO-41)	Active
P4KE51CA-BP	Micro Commercial Co	43.6V	70.1V	5.8A	400W	DO-204AL (DO-41)	Active
P4KE51CA-G	Comchip Technology	43.6V	70.1V	5.71A	400W	DO-204AL (DO-41)	Active
P4KE51CA-TP	Micro Commercial Co	43.6V	70.1V	5.8A	400W	DO-204AL (DO-41)	Active

Engineering Selection Recommendations

Primary Substitutes (Recommended for Direct Replacement)

P4KE51CA (Taiwan Semiconductor Corporation) and P4KE51CA-AP, P4KE51CA-BP, P4KE51CA-TP (Micro Commercial Co variants) are direct electrical equivalents with active product status. These parts maintain the 43.6V reverse standoff voltage, 400W peak pulse power, and DO-204AL (DO-41) package configuration. All are ROHS3 compliant and carry unlimited moisture sensitivity level (MSL 1).

Secondary Substitutes (Enhanced Performance)

P6KE51CA (Taiwan Semiconductor Corporation) offers higher current handling (8.6A vs. 5.8A) and increased power dissipation (600W vs. 400W) while maintaining the 43.6V standoff voltage. This part uses a DO-204AC (DO-15) package, which is mechanically compatible with DO-204AL applications but requires PCB layout verification for axial lead spacing.

Vishay TransZorb® Series Alternatives

BZW04-44B-E3/54 and P4KE51CA-E3/54 provide equivalent electrical performance in the TransZorb® series with active product status and REACH compliance. P4KE51CAHE3/54 includes AEC-Q101 automotive qualification for applications requiring automotive-grade components.

Not Recommended

BZW04-48B has a higher reverse standoff voltage (47.8V) and clamping voltage (77V), making it unsuitable for circuits designed for 43.6V protection thresholds.

Frequently Asked Questions (FAQ)

Q: Can P6KE51CA replace P4KE51C in all applications?

A: P6KE51CA maintains the critical 43.6V reverse standoff voltage and clamping characteristics but uses a DO-15 package instead of DO-41. Mechanical compatibility depends on PCB layout and lead spacing. Electrical performance is equivalent for overvoltage suppression function.

Q: What is the difference between P4KE51CA variants from different manufacturers?

A: P4KE51CA from Taiwan Semiconductor Corporation, Micro Commercial Co (AP, BP, TP variants), and Comchip Technology (P4KE51CA-G) all meet the same electrical specifications: 43.6V standoff, 70.1V clamping, and 400W peak pulse power. Differences exist in packaging format (Tape & Reel vs. Bulk) and operating temperature ranges. Comchip variant operates to 150°C maximum versus 175°C for others.

Q: Is BZW04-48B compatible with P4KE51C?

A: No. BZW04-48B has a 47.8V reverse standoff voltage versus 43.6V for P4KE51C. This higher threshold voltage makes it unsuitable for circuits requiring 43.6V protection activation.

Q: What certifications apply to substitute parts?

A: All substitute parts listed are ROHS3 compliant. P4KE51CAHE3/54 carries AEC-Q101 automotive qualification. Taiwan Semiconductor Corporation and Vishay parts include REACH compliance documentation.

Q: Can I use P4KE51CA-E3/54 in automotive applications?

A: P4KE51CA-E3/54 is not AEC-Q101 qualified. For automotive applications, specify P4KE51CAHE3/54, which carries AEC-Q101 qualification from Vishay.

Q: What is the inventory status for substitute parts?

A: P6KE51CA has the highest inventory (8,595 pcs), followed by P4KE51CAHE3/54 (938 pcs) and BZW04-48B (2,100 pcs). All listed substitutes are in active production with new original stock available.

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