P4SMA18C Equivalent & Substitute Parts

Part Overview

The P4SMA18C is a transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection in surface mount applications. This part operates with a reverse standoff voltage of 15.3V and provides clamping at 26.78V with a peak pulse current rating of 16.1A. The P4SMA18C is classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing design support and procurement.

Substiute Parts

P4SMA18C

Littelfuse Inc.In Stock: 980P4SMA18C Datasheet

Current PartRFQ

P4SMA18CA

Eaton - Electronics DivisionIn Stock: 8744P4SMA18CA Datasheet

DirectRFQ

P4SMA18CA

Eaton - Electronics DivisionIn Stock: 8744P4SMA18CA Datasheet

DirectRFQ

P4SMA18CA-E3/61

Vishay General Semiconductor - Diodes DivisionIn Stock: 462271P4SMA18CA-E3/61 Datasheet

MFR RecommendedRFQ

SMAJP4KE18CA-TP

Micro Commercial CoIn Stock: 1115SMAJP4KE18CA-TP Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the P4SMA18C is determined by matching the following critical electrical parameters: reverse standoff voltage (15.3V), peak pulse current capability (16.1A), power dissipation (400W), and package type (DO-214AC/SMA surface mount). The clamping voltage tolerance range allows for minor variations while maintaining circuit protection integrity. All identified substitutes maintain the same bidirectional channel configuration (1 channel) and zener diode type.

The three substitute parts identified—P4SMA18CA, P4SMA18CA-E3/61, and SMAJP4KE18CA-TP—meet these core electrical requirements. Differences in clamping voltage (25.2V to 25.5V versus 26.78V) and peak pulse current (15.9A to 16.1A) fall within acceptable engineering tolerances for this component category. Operating temperature ranges vary slightly across substitutes but all support the minimum required range.

Parameter Comparison

Engineering Selection Recommendations

All three substitute parts are active products with established supply chains, addressing the obsolescence of the P4SMA18C. Selection among substitutes should be based on the following criteria:

P4SMA18CA (Eaton) and P4SMA18CA-E3/61 (Vishay) are direct electrical equivalents with identical reverse standoff voltage and peak pulse current. P4SMA18CA-E3/61 is the manufacturer-recommended substitute, offering ROHS3 compliance and the full operating temperature range (-65°C ~ 150°C) matching the original part. This part carries the highest inventory availability (462,215 pcs).

SMAJP4KE18CA-TP (Micro Commercial Co) provides equivalent electrical performance with slightly higher clamping voltage (25.5V) and extended upper operating temperature (175°C). This part uses the SMAJ package variant within the DO-214AC family.

For applications requiring strict thermal performance matching the original specification, P4SMA18CA-E3/61 is the preferred selection. For applications with extended temperature requirements, SMAJP4KE18CA-TP offers additional thermal margin.

Frequently Asked Questions (FAQ)

Q: Can P4SMA18CA be used as a direct replacement for P4SMA18C?

A: Yes. Both parts share identical reverse standoff voltage (15.3V), peak pulse current (16.1A), and power dissipation (400W). The clamping voltage difference (25.2V versus 26.78V) is within acceptable tolerance for TVS diode substitution in general-purpose applications.

Q: What is the difference between P4SMA18CA and P4SMA18CA-E3/61?

A: Both are electrically equivalent with 15.3V standoff and 25.2V clamping voltage. P4SMA18CA-E3/61 is manufactured by Vishay and carries ROHS3 compliance. The primary difference is manufacturer and certification status. P4SMA18CA-E3/61 is the manufacturer-recommended substitute.

Q: Is SMAJP4KE18CA-TP compatible with the original P4SMA18C?

A: Yes, with the following considerations: SMAJP4KE18CA-TP maintains the same reverse standoff voltage (15.3V) and peak pulse current (16.1A). The clamping voltage is 25.5V, slightly lower than the original 26.78V. The package is DO-214AC (SMAJ variant), which is mechanically compatible with standard SMA footprints. Operating temperature extends to 175°C, exceeding the original specification.

Q: What are the key parameters that determine substitutability?

A: Substitutability is determined by: reverse standoff voltage (15.3V), peak pulse current capability (16.1A minimum), power dissipation (400W), package type (DO-214AC/SMA family), and bidirectional channel configuration (1 channel). Clamping voltage variations within the 25.2V to 25.5V range are acceptable for general-purpose protection circuits.

Q: Are all substitutes RoHS compliant?

A: P4SMA18CA-E3/61 carries ROHS3 compliance. P4SMA18CA is RoHS compliant. SMAJP4KE18CA-TP compliance status is not specified in available documentation.

Q: What is the moisture sensitivity level for these parts?

A: P4SMA18C, P4SMA18CA, and P4SMA18CA-E3/61 all carry MSL 1 (Unlimited), indicating no moisture sensitivity restrictions. SMAJP4KE18CA-TP MSL rating is not specified.