P4KE33A Equivalent & Substitute Parts

Part Overview

The P4KE33A is a unidirectional transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection applications. This component operates with a reverse standoff voltage of 28.2V and provides peak pulse power dissipation of 400W in a through-hole DO-204AL (DO-41) package. The part is currently active in production with ROHS3 compliance and unlimited moisture sensitivity rating.

Equivalent and substitute parts are necessary when the original P4KE33A becomes unavailable, when alternative packaging or performance characteristics better suit specific application requirements, or when higher power dissipation or current handling capabilities are needed for circuit protection enhancement.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	28.2	V
Voltage - Breakdown (Min)	31.4	V
Voltage - Clamping (Max) @ Ipp	45.7	V
Current - Peak Pulse (10/1000µs)	9	A
Power - Peak Pulse	400	W
Operating Temperature Range	-55 to 175	°C (TJ)
Mounting Type	Through Hole	-
Package / Case	DO-204AL, DO-41, Axial	-
Type	Zener	-
Unidirectional Channels	1	-
RoHS Status	ROHS3 Compliant	-

Substitute Part Grouping Explanation

Substitution eligibility for the P4KE33A is determined by the following critical parameters:

Voltage Parameters: Reverse standoff voltage (28.2V nominal), breakdown voltage minimum (31.4V), and clamping voltage maximum (45.7V) must remain within acceptable tolerance ranges to ensure proper circuit protection without nuisance triggering or excessive voltage stress.

Current and Power Ratings: Peak pulse current (9A minimum) and peak pulse power (400W minimum) establish the minimum protection capability. Substitute parts may exceed these ratings to provide enhanced protection margin.

Package and Mounting: Through-hole axial packages (DO-204AL/DO-41 or DO-204AC/DO-15) are mechanically compatible. Larger packages such as DO-201AE support higher power ratings.

Electrical Type: All substitutes must be unidirectional Zener-type TVS diodes with single channel configuration.

Compliance: ROHS3 compliance and unlimited moisture sensitivity level (MSL 1) are required for equivalent substitution.

Substitute parts are grouped into two categories: direct voltage equivalents maintaining 28.2V standoff voltage, and higher-power variants with modified voltage ratings suitable for applications requiring enhanced transient suppression.

Parameter Comparison

Part Number	Manufacturer	Standoff Voltage (V)	Breakdown Min (V)	Clamp Voltage (V)	Peak Pulse Current (A)	Peak Pulse Power (W)	Package	Status
P4KE33A	Littelfuse Inc.	28.2	31.4	45.7	9	400	DO-204AL (DO-41)	Active
1.5KE33A	Good-Ark Semiconductor	28.2	31.4	45.7	32.8	1500	DO-201AE	Active
P6KE33A	Fairchild Semiconductor	28.2	31.4	45.7	13.8	600	DO-204AC (DO-15)	Active
SA30A	Taiwan Semiconductor Corporation	30	33.3	64.3	10.8	500	DO-204AC (DO-15)	Active
SA28A	Fairchild Semiconductor	28	31.1	45.4	11.2	500	DO-204AC (DO-15)	Obsolete
SA26A	Fairchild Semiconductor	26	28.9	42.1	12.1	500	DO-204AC (DO-15)	Obsolete
SA24A	Fairchild Semiconductor	24	26.7	38.9	13.1	500	DO-204AC (DO-15)	Obsolete
P4KE30A	Taiwan Semiconductor Corporation	25.6	28.5	41.4	10	400	DO-204AL (DO-41)	Active
P6KE30A	Taiwan Semiconductor Corporation	25.6	28.5	41.4	14.5	600	DO-204AC (DO-15)	Active
1.5KE30A-E3/73	Vishay General Semiconductor - Diodes Division	25.6	28.5	41.4	36.2	1500	DO-201AA (DO-27)	Active

Engineering Selection Recommendations

Direct Voltage Equivalent (28.2V Standoff):

The 1.5KE33A and P6KE33A maintain identical voltage specifications to the P4KE33A while offering increased current handling and power dissipation. The 1.5KE33A provides the highest power rating (1500W) in a DO-201AE package, suitable for high-energy transient environments. The P6KE33A offers 600W in a DO-15 package, balancing performance with compact form factor. Both parts are active products with ROHS3 compliance.

Alternative Voltage Ratings:

The P4KE30A and P6KE30A operate at 25.6V standoff voltage, approximately 9% lower than the P4KE33A. These parts are suitable for applications where lower voltage thresholds are acceptable. The 1.5KE30A-E3/73 provides maximum power dissipation (1500W) at this voltage level.

The SA30A operates at 30V standoff voltage, approximately 6% higher than the P4KE33A, and is currently active in production. The SA series parts (SA28A, SA26A, SA24A) are obsolete and should be avoided for new designs despite voltage proximity.

Package Considerations:

DO-204AL (DO-41) packages are limited to 400W power rating. Upgrade to DO-15 (DO-204AC) or DO-27 (DO-201AE) packages when higher power dissipation is required. All substitute parts maintain through-hole axial mounting compatibility.

Compliance and Availability:

All recommended active substitutes maintain ROHS3 compliance and unlimited moisture sensitivity rating. Obsolete SA series parts should not be selected for new applications despite potential voltage compatibility.

Frequently Asked Questions (FAQ)

Q: Can I use P6KE33A as a direct replacement for P4KE33A?

A: Yes. The P6KE33A maintains identical voltage specifications (28.2V standoff, 31.4V breakdown, 45.7V clamp) and provides enhanced current handling (13.8A vs. 9A) and power dissipation (600W vs. 400W). The primary difference is package format: DO-15 versus DO-41. Both are through-hole axial packages with compatible PCB footprints for standard 0.3-inch lead spacing.

Q: What is the difference between 1.5KE33A and P4KE33A?

A: Both maintain identical voltage ratings (28.2V standoff, 45.7V clamp). The 1.5KE33A provides significantly higher peak pulse current (32.8A vs. 9A) and power dissipation (1500W vs. 400W) in a larger DO-201AE package. Selection depends on transient energy requirements: use 1.5KE33A for high-energy applications, P4KE33A for standard protection.

Q: Are SA series parts suitable substitutes?

A: SA series parts (SA24A, SA26A, SA28A, SA30A) are not recommended for new designs. While SA28A and SA30A provide voltage ratings near the P4KE33A specification, these parts carry obsolete product status. SA24A and SA26A have significantly lower voltage ratings (24V and 26V respectively) and are unsuitable for 28.2V standoff applications.

Q: Can I use lower voltage-rated parts like P4KE30A?

A: P4KE30A operates at 25.6V standoff voltage, approximately 9% lower than P4KE33A. This part is suitable only if circuit design tolerates lower protection thresholds. The lower voltage rating results in earlier suppression activation, which may cause nuisance triggering in marginal overvoltage conditions. Verify circuit requirements before substitution.

Q: What package should I select for maximum protection?

A: The 1.5KE33A in DO-201AE package provides maximum power dissipation (1500W) while maintaining 28.2V voltage specifications. This package accommodates higher transient energy and is recommended for applications with severe electromagnetic interference or high-energy pulse environments. Standard DO-41 and DO-15 packages are adequate for typical general-purpose protection applications.

Q: Are all substitute parts ROHS3 compliant?

A: All recommended active substitutes (1.5KE33A, P6KE33A, P4KE30A, P6KE30A, 1.5KE30A-E3/73, SA30A) maintain ROHS3 compliance. Obsolete SA series parts (SA24A, SA26A, SA28A) also carry ROHS3 compliance but should not be selected due to discontinued status.

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