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Home > Products > Circuit Protection > Transient Voltage Suppressors (TVS) > TVS Diodes

Taiwan Semiconductor Corporation P4SMA18C

Name: P4SMA18C
Brand: Taiwan Semiconductor Corporation
SKU: P4SMA18C
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: P4SMA18C

Manufacturer:: Taiwan Semiconductor Corporation

Category:: TVS Diodes

Package:: DO-214AC, SMA

Datasheet:: P4SMA18C.pdf

Description:: 400W, 18V, 10%, BIDIRECTIONAL, T

Quantity:: RFQ Add To RFQ list

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Inventory:7,554

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Product details

Overview

P4SMA18C from Taiwan Semiconductor is a bidirectional surface-mount transient voltage suppressor (TVS) diode designed for robust overvoltage protection in DC power rails and signal lines. It features a 16.2–19.8 V breakdown voltage (V_BR), 14.5 V working stand-off voltage (V_WM), 26.5 V clamping voltage (V_C) at 16.0 A peak pulse current, 400 W peak pulse power rating (10/1000 µs), and operates across –55 °C to +150 °C junction temperature range - deployed in SMPS input stages and automotive DC/DC converters.

For engineers reviewing the P4SMA18C datasheet, P4SMA18C pinout, P4SMA18C application, or P4SMA18C equivalent, this page delivers verified electrical parameters, DO-214AC package dimensions, ISO 7637-2 Pulse 1/2a/2b/3a/3b compliance status, unidirectional vs. bidirectional configuration clarity, and real-world clamping performance under standardized surge waveforms.

Technical Context

The P4SMA18C is a bipolar (bidirectional) TVS diode configured as a single-die, symmetrical avalanche structure - enabling identical clamping behavior in both forward and reverse polarity transients. Its glass-passivated junction ensures stable V_BR tolerance (±5% for 'A' variants; P4SMA18C uses standard tolerance per family spec) and low leakage (<1 µA at V_WM).

It responds to fast-rising ESD and surge events with <1.0 ps intrinsic response time and meets JESD22-A114F (ESD) and ISO 7637-2 (automotive load dump and switching transients). The device is rated for 40 A non-repetitive forward surge (I_FSM) and derates linearly above 25 °C ambient per Fig.2.

Key Specifications

Parameter	Value and Actual Design Meaning
V_WM	14.5 V - Maximum continuous DC or RMS voltage the device blocks without significant leakage; defines safe operating margin below clamping threshold.
V_BR @ I_T=1.0 mA	16.2–19.8 V - Measured breakdown voltage range at 1 mA test current; confirms avalanche onset for transient suppression initiation.
V_C @ I_PPM=16.0 A	26.5 V - Clamped voltage during 10/1000 µs surge; determines maximum stress imposed on downstream circuitry.
P_PPM	400 W - Peak pulse power handling capability; validates survivability against IEC 61000-4-5 Combination Wave (1.2/50 µs & 8/20 µs) surges.
I_R @ V_WM	<1 µA - Reverse leakage at stand-off voltage; ensures minimal power loss and signal integrity in high-impedance monitoring paths.
Junction Temp Range	–55 °C to +150 °C - Enables deployment in under-hood automotive, industrial power supplies, and outdoor lighting without thermal derating concerns.

Pinout & Package

Package: DO-214AC (SMA), surface-mount, molded plastic case with matte tin-plated leads compliant with J-STD-002 solderability and JESD201 Class 2 whisker resistance. Polarity indicated by cathode band - not applicable for bidirectional P4SMA18C; device has no anode/cathode orientation.

Pin/Terminal	Circuit Role	Design Meaning
Anode / Cathode (symmetrical)	Bidirectional avalanche junction terminals	Interchangeable connection points; either terminal may be connected to line or rail - no polarity sensitivity in surge conduction path.

Key Features

Feature	Design Value
Glass passivated junction	Ensures long-term V_BR stability and low parameter drift over temperature and lifetime - critical for automotive-grade reliability.
ISO 7637-2 compliance	Validated for Pulse 1 (inductive load disconnect), Pulse 2a/2b (battery line transients), and Pulse 3a/3b (capacitive coupling noise) - supports full automotive ECU front-end protection.
Moisture sensitivity level 1	Zero bake requirement prior to reflow; compatible with standard SMT assembly processes without floor-life restrictions.
RoHS & halogen-free	Meets IEC 61249-2-21 and EU RoHS Directive 2011/65/EU - enables use in consumer, industrial, and green-energy applications.

Applications

Switching Mode Power Supply (SMPS)	Automotive On-Board DC/DC Converter
Use Scenario: Protection of primary-side MOSFET gate drivers and secondary-side rectifier inputs against turn-off spikes and cross-conduction transients. IC Role / Device Role / Timing Role: Standoff-clamp TVS placed across bulk capacitor or MOSFET drain-source to limit voltage overshoot during switching transitions. Use Value: Limits transient excursions to ≤26.5 V, preventing gate oxide rupture in 30 V-rated controllers and ensuring sustained operation under 400 W surge loads.	Use Scenario: Input rail protection for 12 V → 3.3 V/5 V buck converters powering ADAS sensors and infotainment modules. IC Role / Device Role / Timing Role: Bidirectional clamping element absorbing load-dump pulses (Pulse 5a) and battery reversal transients (Pulse 4) on 12 V supply lines. Use Value: Withstands 40 A I_FSM and maintains <1 µA leakage at 14.5 V, preserving low-quiescent-current design goals while meeting ISO 7637-2 Pulse 1/2a/2b/3a/3b requirements.
LED Driver Power Stage	Industrial PLC Digital Input Module
Use Scenario: Overvoltage suppression on constant-current LED string outputs exposed to cable discharge events and inductive kickback from solenoid drivers. IC Role / Device Role / Timing Role: Fast-response (sub-ps) shunt clamp placed across LED output terminals to divert surge energy before driver IC damage occurs. Use Value: Clamps to 26.5 V within nanoseconds, protecting 30 V-rated LED driver ICs and maintaining luminance stability during field ESD exposure.	Use Scenario: Protection of 24 V digital input optocouplers and signal conditioning circuits against induced surges from nearby motor contactors and relay coils. IC Role / Device Role / Timing Role: Primary-level transient suppressor mounted at PCB edge connector, shunting common-mode surges before they reach isolation barrier. Use Value: Delivers 400 W peak power handling with <1 µA leakage at 14.5 V, enabling high-impedance sensing without false triggering or bias current error.

Switching Mode Power Supply (SMPS)

Automotive On-Board DC/DC Converter

Use Scenario: Protection of primary-side MOSFET gate drivers and secondary-side rectifier inputs against turn-off spikes and cross-conduction transients.

IC Role / Device Role / Timing Role: Standoff-clamp TVS placed across bulk capacitor or MOSFET drain-source to limit voltage overshoot during switching transitions.

Use Value: Limits transient excursions to ≤26.5 V, preventing gate oxide rupture in 30 V-rated controllers and ensuring sustained operation under 400 W surge loads.

Use Scenario: Input rail protection for 12 V → 3.3 V/5 V buck converters powering ADAS sensors and infotainment modules.

IC Role / Device Role / Timing Role: Bidirectional clamping element absorbing load-dump pulses (Pulse 5a) and battery reversal transients (Pulse 4) on 12 V supply lines.

Use Value: Withstands 40 A I_FSM and maintains <1 µA leakage at 14.5 V, preserving low-quiescent-current design goals while meeting ISO 7637-2 Pulse 1/2a/2b/3a/3b requirements.

LED Driver Power Stage

Industrial PLC Digital Input Module

Use Scenario: Overvoltage suppression on constant-current LED string outputs exposed to cable discharge events and inductive kickback from solenoid drivers.

IC Role / Device Role / Timing Role: Fast-response (sub-ps) shunt clamp placed across LED output terminals to divert surge energy before driver IC damage occurs.

Use Value: Clamps to 26.5 V within nanoseconds, protecting 30 V-rated LED driver ICs and maintaining luminance stability during field ESD exposure.

Use Scenario: Protection of 24 V digital input optocouplers and signal conditioning circuits against induced surges from nearby motor contactors and relay coils.

IC Role / Device Role / Timing Role: Primary-level transient suppressor mounted at PCB edge connector, shunting common-mode surges before they reach isolation barrier.

Use Value: Delivers 400 W peak power handling with <1 µA leakage at 14.5 V, enabling high-impedance sensing without false triggering or bias current error.

Equivalent & Alternatives

The following parts are listed as comparable options for similar transient voltage suppression applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
SMBJ18CA (Bourns)	Same DO-214AA package; 400 W rating; tighter V_BR tolerance (±5%); slightly lower V_C (25.6 V @ 15.6 A).	Preferred where board space allows SMB footprint and tighter V_BR matching is required for precision clamping thresholds.	Select SMBJ18CA if layout accommodates larger DO-214AA and ±5% V_BR tolerance is mandatory for system-level margin analysis.
1.5KE18CA (ON Semiconductor)	Through-hole DO-15 package; same 18 V nominal rating; higher V_C (29.1 V @ 13.7 A); 1500 W rating but slower response due to higher junction capacitance.	Suitable only for non-high-speed applications where lead inductance and mounting constraints permit through-hole implementation.	Choose 1.5KE18CA only for legacy through-hole designs or where higher peak power (1500 W) outweighs speed and board-space penalties.

Compared with P4SMA18C, SMBJ18CA offers improved V_BR consistency in a marginally larger package, while 1.5KE18CA trades surface-mount compatibility and sub-nanosecond response for higher absolute surge energy handling - making P4SMA18C optimal for space-constrained, high-speed automotive and industrial DC/DC protection.

Availability

P4SMA18C is available at Aetrix Electronics and suitable for switching mode power supplies, automotive DC/DC converters, and industrial PLC input modules requiring stable component supply, consistent parametric performance, and full traceability across production batches.

Supply support for P4SMA18C includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Taiwan Semiconductor Company (TSC) is a vertically integrated semiconductor manufacturer specializing in discrete power devices, TVS diodes, rectifiers, and MOSFETs - headquartered in Hsinchu Science Park with global distribution and AEC-Q200-qualified product lines.

The P4SMA series belongs to TSC's surface-mount TVS portfolio engineered specifically for automotive-grade transient immunity (ISO 7637-2), industrial power rail hardening, and high-reliability DC/DC converter protection - emphasizing low leakage, tight V_BR spread, and moisture-insensitive packaging.

FAQ

What does the 'C' suffix indicate in P4SMA18C?

The 'C' suffix in P4SMA18C denotes bidirectional configuration - meaning the device provides symmetrical clamping in both polarities, unlike unidirectional variants (e.g., P4SMA18) that require correct anode/cathode orientation. This makes P4SMA18C ideal for AC-coupled lines or systems where voltage polarity reversal is possible. The P4SMA18C achieves this via a back-to-back diode structure within a single DO-214AC package.

Does P4SMA18C meet automotive surge immunity standards?

Yes, P4SMA18C meets ISO 7637-2 Pulse 1 (inductive switch-off), Pulse 2a/2b (battery line transients), and Pulse 3a/3b (capacitive coupling) requirements - confirmed in the official Taiwan Semiconductor datasheet (Version S2102). Its 400 W peak pulse rating, 26.5 V clamping voltage at 16.0 A, and –55 °C to +150 °C operating range make it suitable for front-end protection in automotive ECUs, body control modules, and infotainment power supplies.

What is the maximum clamping voltage of P4SMA18C under surge conditions?

The maximum clamping voltage (V_C) of P4SMA18C is 26.5 V when subjected to a 10/1000 µs waveform with a peak impulse current (I_PPM) of 16.0 A - as specified in the Electrical Specifications table. This value represents the upper limit of voltage seen by protected circuitry during worst-case surge events and is critical for ensuring downstream components (e.g., 30 V-rated MOSFETs or LDOs) remain within safe operating area.

Is P4SMA18C RoHS and halogen-free compliant?

Yes, P4SMA18C is RoHS compliant per EU Directive 2011/65/EU and halogen-free in accordance with IEC 61249-2-21. The device uses molding compound meeting UL 94V-0 flammability rating and matte tin-plated leads qualified to J-STD-002 solderability standards - supporting environmentally regulated applications in consumer electronics, industrial automation, and green energy systems.

What is the junction temperature rating for P4SMA18C?

The P4SMA18C has a maximum junction temperature (T_J_MAX) of +150 °C and a minimum of –55 °C, with storage temperature range matching (–55 °C to +150 °C). This wide thermal envelope enables reliable operation in under-hood automotive environments, enclosed industrial power enclosures, and outdoor LED lighting fixtures - provided PCB copper area and airflow meet thermal dissipation requirements per the Pulse Derating Curve (Fig.2).

P4SMA18C Specifications

Product attributes: Attribute value

Manufacturer:: Taiwan Semiconductor Corporation

Package/Case:: DO-214AC, SMA

Series:: P4SMA

Packaging:: Tape & Reel (TR)

Product Status:: Active

Type:: Zener

Unidirectional Channels:: -

Bidirectional Channels:: 1

Voltage - Reverse Standoff (Typ):: 14.5V

Voltage - Breakdown (Min):: 16.2V

Voltage - Clamping (Max) @ Ipp:: 26.5V

Current - Peak Pulse (10/1000µs):: 16A

Power - Peak Pulse:: 400W

Power Line Protection:: No

Applications:: General Purpose

Capacitance @ Frequency:: -

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: DO-214AC (SMA)

P4SMA18C FAQ

1.How can I place an order for P4SMA18C through Aetrix?

Please submit a Request for Quotation (RFQ) for P4SMA18C on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for P4SMA18C reliable?

The price and inventory of P4SMA18C are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for P4SMA18C is usually 5 days.

3.What payment methods are accepted for P4SMA18C?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for P4SMA18C transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for P4SMA18C?

P4SMA18C orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your P4SMA18C order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for P4SMA18C?

For technical support, including P4SMA18C datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your P4SMA18C requirements.

6.How does Aetrix verify that P4SMA18C is sourced from the original manufacturer or authorized distributors?

All P4SMA18C products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that P4SMA18C meets industry standards.

7.What is the process for return or replacement of P4SMA18C?

All P4SMA18C units undergo pre-shipment inspection (PSI). If there is an issue with P4SMA18C, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The P4SMA18C part is unused and in its original packaging.

Return procedure for P4SMA18C:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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