P4KE39A-B Equivalent & Substitute Parts

Part Overview

The P4KE39A-B is a unidirectional transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., rated for 33.3V reverse standoff voltage with a 53.9V clamping voltage at peak pulse current. This component is designed for general-purpose transient voltage suppression in through-hole applications using the DO-204AL (DO-41) axial package. The part is currently active and ROHS3 compliant with unlimited moisture sensitivity rating.

Equivalent and substitute parts are necessary when the original part number becomes unavailable, when alternative packaging formats are required for manufacturing processes, or when higher power dissipation capabilities are needed while maintaining compatible electrical characteristics.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	33.3	V
Voltage - Breakdown (Min)	37.1	V
Voltage - Clamping (Max) @ Ipp	53.9	V
Current - Peak Pulse (10/1000µs)	7.6	A
Power - Peak Pulse	400	W
Operating Temperature Range	-55 to 175	°C (TJ)
Package / Case	DO-204AL, DO-41, Axial	—
Mounting Type	Through Hole	—
Type	Zener	—
Unidirectional Channels	1	—

Substitute Part Grouping Explanation

Substitution of the P4KE39A-B is determined by the following critical electrical parameters: voltage reverse standoff (33.3V nominal), voltage clamping at peak pulse current (53.9V maximum), and peak pulse current capability (7.6A). All substitute parts must maintain these core voltage specifications within the allowed tolerance range to ensure proper transient suppression performance.

Substitute parts are grouped into three categories based on package type and power dissipation capability:

Category 1: Direct Package Equivalent (DO-204AL / DO-41) Parts maintaining the same DO-204AL (DO-41) axial package with identical electrical specifications. These provide direct mechanical and electrical interchangeability.

Category 2: Higher Power Dissipation (DO-201 Package) Parts with 1500W peak pulse power rating in the larger DO-201 package, maintaining the same voltage specifications but with increased current handling capability (26A to 31A). These are suitable for applications requiring enhanced thermal performance.

Category 3: Intermediate Power Dissipation (DO-15 Package) Parts with 600W peak pulse power rating in the DO-15 package, providing a middle ground between the original 400W specification and the 1500W alternatives.

Parameter Comparison

Part Number	Manufacturer	Vwm (V)	Vc (V)	Ipp (A)	Power (W)	Package	Status
P4KE39A-B	Littelfuse Inc.	33.3	53.9	7.6	400	DO-204AL	Active
P4KE39A-TP	Micro Commercial Co	33.3	53.9	7.6	400	DO-41	Active
P4KE39A	Taiwan Semiconductor Corporation	33.3	53.9	7.7	400	DO-204AL	Active
1.5KE39A	Taiwan Semiconductor Corporation	33.3	53.9	29	1500	DO-201	Active
1.5KE36A	Taiwan Semiconductor Corporation	30.8	49.9	31	1500	DO-201	Active
1.5KE43A	Taiwan Semiconductor Corporation	36.8	59.3	26	1500	DO-201	Active
P6KE36A	Fairchild Semiconductor	30.8	49.9	12.6	600	DO-15	Active
P6KE43A	Diotec Semiconductor	36.8	59.3	10.6	600	DO-15	Active
SA33A	Fairchild Semiconductor	33	53.3	9.4	500	DO-15	Obsolete

Engineering Selection Recommendations

Direct Substitutes (Recommended for Pin-Compatible Replacement)

P4KE39A-TP and P4KE39A maintain identical electrical specifications (33.3V standoff, 53.9V clamping, 7.6A peak pulse) with the same 400W power rating. Both are active products with ROHS3 compliance. P4KE39A-TP is supplied in cut tape format, while P4KE39A is supplied in tape and reel format. These parts are suitable for direct substitution in existing designs without circuit modification.

Higher Power Alternatives (For Enhanced Thermal Performance)

The 1.5KE series (1.5KE39A, 1.5KE36A, 1.5KE43A) offers 1500W peak pulse power dissipation in the larger DO-201 package. The 1.5KE39A maintains exact voltage specifications (33.3V standoff, 53.9V clamping) with increased current handling (29A). These parts are suitable when thermal management or higher transient current capacity is required. All are active products with ROHS3 compliance.

Intermediate Power Alternatives (For Moderate Power Requirements)

The P6KE series (P6KE36A, P6KE43A) and SA33A provide 600W to 500W power dissipation in the DO-15 package. SA33A is obsolete and should not be selected for new designs. P6KE36A and P6KE43A are active products with ROHS3 compliance, offering a compromise between the original 400W specification and the 1500W alternatives.

All recommended active substitutes maintain the -55°C to 175°C operating temperature range and are ROHS3 compliant with EAR99 export classification.

Frequently Asked Questions (FAQ)

Q: Can P4KE39A-TP be used as a direct replacement for P4KE39A-B?

A: Yes. Both parts have identical electrical specifications (33.3V standoff, 53.9V clamping, 7.6A peak pulse, 400W power) and use the same DO-204AL (DO-41) axial package. The difference is packaging format: P4KE39A-TP is supplied in cut tape, while P4KE39A-B is supplied in bulk. Both are active products with ROHS3 compliance.

Q: What is the difference between the 1.5KE39A and the original P4KE39A-B?

A: The 1.5KE39A maintains identical voltage specifications (33.3V standoff, 53.9V clamping) but offers significantly higher power dissipation (1500W versus 400W) and peak pulse current (29A versus 7.6A). The package is larger (DO-201 versus DO-204AL), requiring PCB layout modification. This part is suitable when higher transient energy absorption is required.

Q: Can I use 1.5KE36A or 1.5KE43A instead of 1.5KE39A?

A: 1.5KE36A has lower voltage specifications (30.8V standoff, 49.9V clamping) and is suitable only for applications with lower voltage transients. 1.5KE43A has higher voltage specifications (36.8V standoff, 59.3V clamping) and is suitable for higher voltage applications. Neither is a direct substitute for 1.5KE39A without circuit analysis.

Q: Is SA33A still available for new designs?

A: No. SA33A is obsolete and should not be selected for new designs. Active alternatives include P6KE36A (600W, DO-15 package) or 1.5KE39A (1500W, DO-201 package).

Q: What are the package differences between DO-204AL, DO-201, and DO-15?

A: DO-204AL (DO-41) is the smallest axial package used in the original P4KE39A-B. DO-201 (DO-27) is a larger axial package used in the 1.5KE series, accommodating higher power dissipation. DO-15 (DO-204AC) is an intermediate axial package used in the P6KE series. Package selection affects PCB layout, thermal performance, and current handling capability.

Q: Are all substitute parts ROHS3 compliant?

A: All active substitute parts listed are ROHS3 compliant. SA33A, which is obsolete, is also ROHS3 compliant but should not be used in new designs.

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