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

Diodes Incorporated SMAJ18AQ-13-F

Name: SMAJ18AQ-13-F
Brand: Diodes Incorporated
SKU: SMAJ18AQ-13-F
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SMAJ18AQ-13-F

Manufacturer:: Diodes Incorporated

Category:: TVS Diodes

Package:: DO-214AC, SMA

Datasheet:: SMAJ18AQ-13-F.pdf

Description:: TVS DIODE 18VWM 29.2VC SMA

Quantity:: RFQ Add To RFQ list

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Inventory:9,623

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Product details

Overview

SMAJ18AQ-13-F from Diodes Incorporated is a unidirectional 400W automotive transient voltage suppressor (TVS) diode with 18V reverse standoff voltage, 29.2V max clamping voltage at 13.7A peak pulse current, and AEC-Q101 qualification. It protects CAN, LIN, and sensor interface circuits in engine control units and body electronics against ISO7637-2 Pulse 1 (−100V), Pulse 2a (+50V), and ISO10605 ESD (±30kV).

For engineers reviewing the SMAJ18AQ-13-F datasheet, SMAJ18AQ-13-F pinout, SMAJ18AQ-13-F application, or SMAJ18AQ-13-F equivalent, this page delivers verified clamping performance, AEC-Q101 compliance status, IATF 16949 manufacturing evidence, and direct comparison to industry-standard TVS alternatives for automotive power rail protection.

Technical Context

This unidirectional TVS operates as a fast-acting shunt clamp on DC power lines, triggering at 20.0–22.1V breakdown (V_BR) with ≤0.5µA leakage at 18V (V_RWM). Its glass-passivated junction enables stable surge response across −55°C to +175°C junction temperature range.

Designed for single-pulse transients per ISO7637-2 and ISO10605 waveforms, it sustains 400W peak pulse power (10×1000µs) and 40A non-repetitive forward surge (8.3ms half-sine), with thermal derating to 1.0W steady-state at +75°C lead temperature.

Key Specifications

Parameter	Value and Actual Design Meaning
Peak Pulse Power	400W - Clamps 10×1000µs transients without failure under ISO7637-2 stress conditions.
Reverse Standoff Voltage	18V - Blocks normal 12V/24V automotive battery operation while remaining inactive below surge threshold.
Max Clamping Voltage	29.2V @ 13.7A - Limits downstream IC voltage to safe level during worst-case ISO7637-2 Pulse 1 (−100V) event.
Breakdown Voltage	20.0–22.1V @ 1.0mA - Ensures reliable turn-on margin above 18V system rail with controlled V_BR distribution.
Leakage Current	≤0.5µA @ 18V - Prevents parasitic drain on always-on vehicle modules such as alarm controllers and telematics.
AEC-Q101 Qualified	Yes - Validated for automotive use with PPAP capability and production in IATF 16949-certified facilities.

Pinout & Package

Package: SMA (DO-214AC), surface-mount, molded plastic UL 94V-0 housing; cathode band denotes polarity; weight ≈0.064g; moisture sensitivity level 1.

Pin/Terminal	Circuit Role	Design Meaning
Anode	Current sink during reverse-biased surge	Connected to protected line (e.g., CAN_H); conducts surge current to ground when clamped.
Cathode	Reference node / surge return path	Typically tied to chassis or system ground; defines polarity and establishes clamping reference point.

Key Features

Feature	Design Value
400W peak pulse power	Withstands ISO7637-2 Pulse 1 (−100V) and Pulse 3a (−150V) without degradation in engine bay environments.
Glass-passivated die	Ensures long-term stability of V_BR and leakage under thermal cycling (−55°C to +175°C TJ).
Lead-free, halogen-free "Green" construction	Meets RoHS 3 (2015/863/EU) and automotive ELV Directive requirements with <900ppm Br+Cl, <1000ppm Sb.
Uni-directional configuration	Optimized for DC power rails where ground-referenced surges dominate; avoids false triggering on positive transients.

Applications

Engine Control Unit (ECU) Power Input

CAN Bus Physical Layer Protection

Use Scenario: 12V battery feed to microcontroller power supply in under-hood ECU exposed to load dump and alternator ripple.

IC Role / Device Role / Timing Role: Shunt TVS diode placed between V_BAT and GND, clamping transients before LDO input.

Use Value: Limits voltage to ≤29.2V during ISO7637-2 Pulse 1 (−100V), preventing LDO overvoltage failure and MCU brownout.

Use Scenario: Protection of CAN transceiver pins (CAN_H/CAN_L) against ESD and coupled noise in vehicle wiring harnesses.

IC Role / Device Role / Timing Role: Unidirectional TVS on each CAN line referenced to ground, activated only during negative surges.

Use Value: Maintains signal integrity by clamping ISO10605 ±30kV contact discharge without affecting 0–5V differential CAN signaling.

Body Control Module (BCM) Sensor Inputs

Automotive Lighting Driver Supply

Use Scenario: 5V/12V analog sensor inputs (e.g., temperature, pressure) in BCM subject to cable-induced transients.

IC Role / Device Role / Timing Role: Low-leakage (≤0.5µA) TVS placed at connector entry point, upstream of signal conditioning op-amps.

Use Value: Prevents sensor offset drift and ADC saturation during ISO7637-2 Pulse 3b (+100V) events while adding negligible DC error.

Use Scenario: 24V LED driver input in headlamp module subjected to jump-start surges and relay switching spikes.

IC Role / Device Role / Timing Role: Primary overvoltage clamp on main power rail feeding buck controller and LED strings.

Use Value: Absorbs 400W peak energy from 24V load dump (ISO7637-2 Pulse 2a: +50V) without requiring bulk capacitance redesign.

Equivalent & Alternatives

The following parts are listed as comparable options for similar unidirectional automotive TVS applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
SMAJ18A-13-F	No AEC-Q101 qualification; standard industrial grade; same electrical specs and SMA package.	Not approved for automotive production; suitable for prototyping or non-safety-critical industrial systems.	Select only if AEC-Q101 documentation and PPAP support are not required.
SMCJ18A-Q	Higher 1500W peak power; DO-214AB (SMC) package; same 18V V_RWM, 29.2V V_C, AEC-Q101 qualified.	Used where higher surge margin is needed (e.g., alternator output lines); larger footprint limits PCB density.	Choose when system-level testing reveals insufficient margin with 400W rating, and board space allows SMC package.

Compared with SMAJ18AQ-13-F, SMAJ18A-13-F lacks automotive qualification documentation and traceability, while SMCJ18A-Q trades compact SMA size for 3.75× higher surge capacity-making the SMAJ18AQ optimal for space-constrained, production-grade 12V/24V automotive nodes requiring certified reliability.

Availability

SMAJ18AQ-13-F is available at Aetrix Electronics and suitable for engine control units, CAN bus interfaces, and body electronics requiring stable component supply with full automotive qualification traceability.

Supply support for SMAJ18AQ-13-F 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

Diodes Incorporated is a global semiconductor manufacturer specializing in discrete, analog, and mixed-signal solutions, with design centers in Asia, Europe, and the US.

The SMAJ(AQ) series targets automotive electronics, delivering AEC-Q101-qualified TVS diodes optimized for ISO7637-2 and ISO10605 compliance in space-constrained surface-mount applications.

FAQ

What is the maximum operating junction temperature for SMAJ18AQ-13-F?

The device supports continuous operation from −55°C to +175°C junction temperature, validated per AEC-Q101 stress test conditions including high-temperature operating life (HTOL) and temperature cycling. Derating begins above +25°C ambient for pulse power, and steady-state dissipation drops to 1.0W at +75°C lead temperature.

Is SMAJ18AQ-13-F compatible with lead-free reflow soldering processes?

Yes-it features matte tin lead-free plating, qualified to MIL-STD-202 Method 208, and rated for standard Pb-free reflow profiles (peak 260°C). The SMA package meets J-STD-020 moisture sensitivity level 1, eliminating bake requirements prior to assembly.

How does the clamping voltage of SMAJ18AQ-13-F compare to its breakdown voltage?

V_C = 29.2V at I_PP = 13.7A, while V_BR (min) = 20.0V at I_T = 1.0mA. This 46% overvoltage margin ensures robust turn-on behavior and prevents premature conduction during normal operation while maintaining tight clamping during transients.

Can SMAJ18AQ-13-F be used in bi-directional signal lines like RS-485?

No-it is unidirectional only, with cathode-anode polarity. For bidirectional data lines, Diodes' SMAJ18CAQ-13-F (bi-directional variant) must be used; using SMAJ18AQ-13-F would short the signal during positive half-cycles due to forward conduction.

SMAJ18AQ-13-F Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Package/Case:: DO-214AC, SMA

Series:: -

Packaging:: Tape & Reel (TR)

Product Status:: Active

Type:: Zener

Unidirectional Channels:: 1

Bidirectional Channels:: -

Voltage - Reverse Standoff (Typ):: 18V

Voltage - Breakdown (Min):: 20V

Voltage - Clamping (Max) @ Ipp:: 29.2V

Current - Peak Pulse (10/1000µs):: 13.7A

Power - Peak Pulse:: 400W

Power Line Protection:: No

Applications:: -

Capacitance @ Frequency:: -

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

Grade:: Automotive

Qualification:: AEC-Q101

Mounting Type:: Surface Mount

Supplier Device Package:: SMA

SMAJ18AQ-13-F FAQ

1.How can I place an order for SMAJ18AQ-13-F through Aetrix?

Please submit a Request for Quotation (RFQ) for SMAJ18AQ-13-F 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 SMAJ18AQ-13-F reliable?

The price and inventory of SMAJ18AQ-13-F are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ18AQ-13-F is usually 5 days.

3.What payment methods are accepted for SMAJ18AQ-13-F?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ18AQ-13-F transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SMAJ18AQ-13-F?

SMAJ18AQ-13-F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SMAJ18AQ-13-F 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 SMAJ18AQ-13-F?

For technical support, including SMAJ18AQ-13-F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ18AQ-13-F requirements.

6.How does Aetrix verify that SMAJ18AQ-13-F is sourced from the original manufacturer or authorized distributors?

All SMAJ18AQ-13-F 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 SMAJ18AQ-13-F meets industry standards.

7.What is the process for return or replacement of SMAJ18AQ-13-F?

All SMAJ18AQ-13-F units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ18AQ-13-F, 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 SMAJ18AQ-13-F part is unused and in its original packaging.

Return procedure for SMAJ18AQ-13-F:

1.Submit a request within 90 days.

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

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