P4SMA18A Equivalent & Substitute Parts

Part Overview

The P4SMA18A is a unidirectional Transient Voltage Suppressor (TVS) diode in DO-214AC (SMA) surface mount package, designed for general purpose transient voltage protection applications. The main part manufactured by onsemi carries an obsolete product status. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications utilizing this TVS diode specification.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	15.3	V
Voltage - Breakdown (Min)	17.1	V
Voltage - Clamping (Max) @ Ipp	25.2	V
Current - Peak Pulse (10/1000µs)	15.9	A
Power - Peak Pulse	400	W
Operating Temperature Range	-65°C ~ 150°C	TJ
Package / Case	DO-214AC, SMA	—
Mounting Type	Surface Mount	—
Type	Zener	—
Unidirectional Channels	1	—

Substitute Part Grouping Explanation

Substitution of the P4SMA18A TVS diode is determined by strict equivalence across the following electrical and mechanical parameters:

Voltage - Reverse Standoff (Typ): 15.3V
Voltage - Breakdown (Min): 17.1V
Voltage - Clamping (Max) @ Ipp: 25.2V or 25.5V (within acceptable tolerance)
Current - Peak Pulse (10/1000µs): 15.9A or 16.1A (within acceptable tolerance)
Power - Peak Pulse: 400W
Package / Case: DO-214AC, SMA
Mounting Type: Surface Mount
Type: Zener, Unidirectional (1 channel)

Substitute parts are grouped into two categories:

Direct Equivalents: Parts with identical or near-identical electrical specifications and the same package designation.

Similar Equivalents: Parts meeting all electrical parameters within acceptable tolerance ranges but with minor package or manufacturer variations (e.g., DO-214AC SMAJ variant).

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff (Typ)	Voltage - Breakdown (Min)	Voltage - Clamping (Max) @ Ipp	Current - Peak Pulse (10/1000µs)	Power - Peak Pulse	Operating Temperature	Package	Product Status
P4SMA18A	onsemi	15.3V	17.1V	25.2V	15.9A	400W	-65°C ~ 150°C	DO-214AC (SMA)	Obsolete
P4SMA18A	Fairchild Semiconductor	15.3V	17.1V	25.5V	16.1A	400W	-65°C ~ 150°C	DO-214AC (SMA)	Obsolete
P4SMA18A-E3/5A	Vishay General Semiconductor - Diodes Division	15.3V	17.1V	25.2V	15.9A	400W	-65°C ~ 150°C	DO-214AC (SMA)	Active
P4SMA18A-M3/61	Vishay General Semiconductor - Diodes Division	15.3V	17.1V	25.2V	15.9A	400W	-65°C ~ 150°C	DO-214AC (SMA)	Active
SMAJP4KE18A-TP	Micro Commercial Co	15.3V	17.1V	25.5V	16.1A	400W	-55°C ~ 175°C	DO-214AC (SMAJ)	Active

Engineering Selection Recommendations

Primary Substitutes (Direct Equivalents):

P4SMA18A-E3/5A and P4SMA18A-M3/61 (both Vishay General Semiconductor - Diodes Division) are the preferred direct substitutes. Both parts maintain identical electrical specifications to the original onsemi P4SMA18A, are RoHS3 compliant, and carry active product status. These parts are available in Tape & Reel packaging with established supply chain availability.

Secondary Substitute (Similar Equivalent):

SMAJP4KE18A-TP (Micro Commercial Co) meets all electrical parameters within acceptable tolerance and is RoHS3 compliant with active product status. This part features an extended operating temperature range (-55°C ~ 175°C) compared to the original specification (-65°C ~ 150°C). The package designation is DO-214AC (SMAJ) rather than standard SMA, which may require PCB footprint verification for mechanical compatibility.

Fairchild Semiconductor P4SMA18A:

The Fairchild Semiconductor variant carries obsolete product status and is not recommended for new designs despite electrical equivalence.

Frequently Asked Questions (FAQ)

Q: Can P4SMA18A-E3/5A be used as a direct replacement for the onsemi P4SMA18A?

A: Yes. The P4SMA18A-E3/5A maintains identical electrical specifications (15.3V standoff, 25.2V clamping, 15.9A peak pulse current, 400W peak power) and the same DO-214AC (SMA) package. Both are unidirectional Zener TVS diodes with identical operating temperature ranges. The part is RoHS3 compliant and carries active product status.

Q: What is the difference between P4SMA18A-E3/5A and P4SMA18A-M3/61?

A: Both parts are manufactured by Vishay General Semiconductor - Diodes Division and share identical electrical specifications and package designation. The suffix designations (-E3/5A and -M3/61) indicate different tape and reel configurations or manufacturing date codes. Electrical performance and compatibility are equivalent.

Q: Can SMAJP4KE18A-TP replace the original P4SMA18A?

A: SMAJP4KE18A-TP meets all electrical parameters within acceptable tolerance (15.3V standoff, 25.5V clamping, 16.1A peak pulse current, 400W peak power). However, the package designation is DO-214AC (SMAJ) rather than standard SMA. PCB footprint compatibility must be verified before substitution, as SMAJ and SMA packages may have different lead configurations or spacing.

Q: Why is the onsemi P4SMA18A listed as obsolete?

A: Obsolete product status indicates the manufacturer has discontinued production and support. Substitute parts with active product status ensure ongoing availability and manufacturer support for future production requirements.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All substitute parts listed (P4SMA18A-E3/5A, P4SMA18A-M3/61, and SMAJP4KE18A-TP) are RoHS3 compliant. The original onsemi P4SMA18A does not specify RoHS status.

Q: What is the operating temperature difference between SMAJP4KE18A-TP and other substitutes?

A: SMAJP4KE18A-TP operates across -55°C ~ 175°C, compared to -65°C ~ 150°C for the original P4SMA18A and other direct substitutes. The extended upper temperature limit may be advantageous in high-temperature applications, while the higher minimum operating temperature (-55°C vs -65°C) may be a constraint in extreme cold environments.

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