P4SMA18 Equivalent & Substitute Parts

Part Overview

The P4SMA18 is a unidirectional Transient Voltage Suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose transient voltage protection in surface-mount applications. This component features a 15.3V reverse standoff voltage and 26.78V maximum clamping voltage with 16.1A peak pulse current capability in a DO-214AC (SMA) package. The part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

Substiute Parts

P4SMA18

Littelfuse Inc.In Stock: 1105P4SMA18 Datasheet

Current PartRFQ

P4SMA18A

Fairchild SemiconductorIn Stock: 165157P4SMA18A Datasheet

MFR RecommendedRFQ

P4SMA18A

Fairchild SemiconductorIn Stock: 165157P4SMA18A Datasheet

MFR RecommendedRFQ

SMAJP4KE18A-TP

Micro Commercial CoIn Stock: 5523SMAJP4KE18A-TP Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the P4SMA18 is determined by the following critical parameters that must remain consistent across equivalent parts:

• Voltage - Reverse Standoff (Typ): 15.3V
• Unidirectional Channels: 1
• Current - Peak Pulse (10/1000µs): 16.1A
• Power - Peak Pulse: 400W
• Package / Case: DO-214AC, SMA
• Mounting Type: Surface Mount
• Type: Zener

The identified substitute parts maintain these core electrical and mechanical specifications. Variations in clamping voltage (26.78V vs. 25.5V) and operating temperature ranges are within acceptable tolerance for general-purpose TVS applications while preserving the primary protection function.

Parameter Comparison

Engineering Selection Recommendations

P4SMA18A (Fairchild Semiconductor) serves as the primary equivalent substitute, maintaining identical reverse standoff voltage, peak pulse current, and power dissipation specifications. Both the original P4SMA18 and P4SMA18A are classified as obsolete; however, P4SMA18A offers higher current inventory availability (165,100 pcs) compared to the original part (1,001 pcs).

SMAJP4KE18A-TP (Micro Commercial Co) represents an active product alternative with extended operating temperature range (-55°C ~ 175°C vs. -65°C ~ 150°C) and superior long-term availability. This part exhibits a lower maximum clamping voltage (25.5V vs. 26.78V), which provides improved transient suppression performance. All three parts maintain ROHS3 compliance and identical electrical performance for general-purpose TVS applications.

Frequently Asked Questions (FAQ)

Q: Can P4SMA18A directly replace P4SMA18 in existing designs?

A: Yes. P4SMA18A maintains identical reverse standoff voltage (15.3V), peak pulse current (16.1A), and power dissipation (400W). The clamping voltage difference (25.5V vs. 26.78V) represents improved protection performance. Both parts use DO-214AC (SMA) packaging and are surface-mount compatible.

Q: What is the difference between P4SMA18A and SMAJP4KE18A-TP?

A: Both parts share identical electrical specifications for reverse standoff voltage, peak pulse current, and power dissipation. SMAJP4KE18A-TP is an active product with extended operating temperature range (-55°C ~ 175°C) and lower maximum clamping voltage (25.5V). The package designation differs slightly (SMAJ vs. SMA), though both are DO-214AC form factors suitable for surface-mount assembly.

Q: Why is the original P4SMA18 obsolete?

A: Product obsolescence is determined by manufacturer lifecycle decisions. Equivalent parts P4SMA18A and SMAJP4KE18A-TP provide continued access to the same electrical performance and protection function.

Q: Are all three parts RoHS compliant?

A: Yes. P4SMA18, P4SMA18A, and SMAJP4KE18A-TP are all ROHS3 compliant.

Q: Which substitute offers the best long-term availability?

A: SMAJP4KE18A-TP is classified as an active product, providing superior long-term procurement stability compared to the obsolete P4SMA18 and P4SMA18A alternatives.