Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

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

Taiwan Semiconductor Corporation SMAJ9.0

Name: SMAJ9.0
Brand: Taiwan Semiconductor Corporation
SKU: SMAJ9.0
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: SMAJ9.0

Manufacturer:: Taiwan Semiconductor Corporation

Category:: TVS Diodes

Package:: DO-214AC, SMA

Datasheet:: SMAJ9.0.pdf

Description:: 400W, 11.1V, 10%, UNIDIRECTIONAL

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:9,103

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

SMAJ9.0 from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, designed for clamping fast transients in DC power lines. It features a 9.0 V working stand-off voltage (V_WM), 10.0–12.2 V breakdown voltage (V_BR @ 1 mA), 16.9 V maximum clamping voltage (V_C) at 5 A peak pulse current, and 400 W peak pulse power rating per 10/1000 µs waveform - suitable for protecting SMPS inputs and DC/DC converter rails.

For engineers reviewing the SMAJ9.0 datasheet, SMAJ9.0 pinout, SMAJ9.0 application, or SMAJ9.0 equivalent, this page delivers verified electrical parameters, DO-214AC mechanical interface details, clamping performance under ISO 7637-2 Pulse 1/2a/2b/3a/3b, moisture sensitivity level 1 compliance, and direct alternative part comparisons for automotive and industrial power rail protection.

Technical Context

The SMAJ9.0 operates as a unidirectional avalanche diode with glass-passivated junction, delivering sub-1 ps response time from 0 V to V_BR(min). Its clamping action begins at 10.0 V (min V_BR) and limits transient energy to ≤16.9 V at 5 A IPPM, enabling robust protection of 9 V nominal systems without false triggering during normal operation.

It supports steady-state power dissipation of 1 W and withstands 40 A non-repetitive forward surge (8.3 ms half-sine), with operating junction temperature range from –55 °C to +150 °C. The device meets JESD201 Class 2 whisker resistance and UL 94V-0 flammability requirements for high-reliability PCB assembly.

Key Specifications

Parameter	Value and Actual Design Meaning
V_WM	9.0 V - Maximum continuous reverse voltage before leakage exceeds 5 µA; sets upper limit for safe DC rail operation.
V_BR @ I_T = 1 mA	10.0–12.2 V - Breakdown threshold range; ensures reliable turn-on during overvoltage events above nominal 9 V supply.
V_C @ I_PPM = 5 A	16.9 V - Clamped voltage during 10/1000 µs transient; protects downstream 12 V logic or analog circuitry.
P_PPM	400 W - Peak pulse power handling per standard 10/1000 µs waveform; sufficient for ISO 7637-2 Pulse 1 (inductive load dump) suppression.
I_R @ V_WM	5 µA - Reverse leakage at 9.0 V; low enough to avoid loading 9 V bias networks or battery-powered circuits.
Package	DO-214AC (SMA) - Surface-mount outline with cathode band marking; compatible with automated pick-and-place and reflow soldering.

Pinout & Package

DO-214AC (SMA) package: molded plastic case with matte tin-plated leads, polarity indicated by cathode band. Weight ≈ 0.060 g. Meets J-STD-002 solderability and JESD201 Class 2 whisker resistance standards.

Pin/Terminal	Circuit Role	Design Meaning
Anode	Low-side reference terminal	Connected to ground or lower-potential node; completes clamping path during positive transients on cathode side.
Cathode	High-side transient input	Connected to protected line (e.g., 9 V rail); conducts avalanche current to anode when V_AK ≥ V_BR.

Key Features

Feature	Design Value
Glass passivated junction	Ensures stable V_BR tolerance and long-term reliability under thermal cycling and humidity exposure.
Sub-1 ps response time	Clamps ESD and fast-switching noise before sensitive ICs experience overstress - critical for USB, CAN, or sensor interfaces.
ISO 7637-2 compliance	Validated for automotive load-dump (Pulse 2b), inductive switching (Pulse 1), and supply interruption (Pulse 3a/3b) immunity.
Moisture sensitivity level 1	Zero bake requirement prior to reflow; enables immediate use from tape-and-reel without floor-life management.

Applications

Switching Mode Power Supply (SMPS)	On-board DC/DC Converter
Use Scenario: Input stage of 9 V-output flyback or buck converter subjected to line surges and MOSFET switching spikes. IC Role / Device Role / Timing Role: Unidirectional TVS placed between input rail and ground to clamp positive transients before they reach controller IC or primary-side FET gate driver. Use Value: Limits voltage excursion to ≤16.9 V during 400 W pulses, preventing latch-up or gate oxide damage in 12 V-rated controllers.	Use Scenario: Output rail of isolated 9 V DC/DC module powering microcontroller peripherals in industrial PLC I/O modules. IC Role / Device Role / Timing Role: Secondary-side TVS connected across output capacitor to absorb reflected transients from load switching or cable ESD events. Use Value: Maintains regulated 9 V output integrity during 5 A transient events, avoiding brownout resets or ADC reference corruption.
Automotive Lighting Control	Industrial Adapter Protection
Use Scenario: LED driver input in headlamp ECU exposed to battery load-dump pulses up to 120 V during alternator regulation failure. IC Role / Device Role / Timing Role: First-line clamping device on 9–12 V supply rail, absorbing energy before it reaches LED driver IC and current-sense amplifier. Use Value: Withstands 40 A surge (8.3 ms) and clamps 100 V transients to <17 V, preserving PWM dimming accuracy and thermal shutdown thresholds.	Use Scenario: AC/DC adapter secondary-side output feeding 9 V wall-wart powered IoT gateway with Ethernet and Zigbee radios. IC Role / Device Role / Timing Role: Rail protector between rectifier/filter stage and LDO regulator, suppressing conducted noise from mains and nearby RF sources. Use Value: 5 µA leakage avoids depleting standby current budget; 16.9 V clamping prevents LDO dropout or radio PLL unlock during 10/1000 µs line disturbances.

Switching Mode Power Supply (SMPS)

On-board DC/DC Converter

Use Scenario: Input stage of 9 V-output flyback or buck converter subjected to line surges and MOSFET switching spikes.

IC Role / Device Role / Timing Role: Unidirectional TVS placed between input rail and ground to clamp positive transients before they reach controller IC or primary-side FET gate driver.

Use Value: Limits voltage excursion to ≤16.9 V during 400 W pulses, preventing latch-up or gate oxide damage in 12 V-rated controllers.

Use Scenario: Output rail of isolated 9 V DC/DC module powering microcontroller peripherals in industrial PLC I/O modules.

IC Role / Device Role / Timing Role: Secondary-side TVS connected across output capacitor to absorb reflected transients from load switching or cable ESD events.

Use Value: Maintains regulated 9 V output integrity during 5 A transient events, avoiding brownout resets or ADC reference corruption.

Automotive Lighting Control

Industrial Adapter Protection

Use Scenario: LED driver input in headlamp ECU exposed to battery load-dump pulses up to 120 V during alternator regulation failure.

IC Role / Device Role / Timing Role: First-line clamping device on 9–12 V supply rail, absorbing energy before it reaches LED driver IC and current-sense amplifier.

Use Value: Withstands 40 A surge (8.3 ms) and clamps 100 V transients to <17 V, preserving PWM dimming accuracy and thermal shutdown thresholds.

Use Scenario: AC/DC adapter secondary-side output feeding 9 V wall-wart powered IoT gateway with Ethernet and Zigbee radios.

IC Role / Device Role / Timing Role: Rail protector between rectifier/filter stage and LDO regulator, suppressing conducted noise from mains and nearby RF sources.

Use Value: 5 µA leakage avoids depleting standby current budget; 16.9 V clamping prevents LDO dropout or radio PLL unlock during 10/1000 µs line disturbances.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
SMAJ9.0A	Narrower V_BR range (10.0–11.1 V vs. 10.0–12.2 V); lower V_C = 15.4 V at 5 A; tighter tolerance improves consistency in precision 9 V systems.	Better suited for designs requiring minimal clamping overshoot where 15.4 V is acceptable vs. 16.9 V.	Select SMAJ9.0A when tighter V_BR distribution and lower clamping voltage are prioritized over cost or legacy design compatibility.
SMBJ9.0	Same V_WM/V_BR/V_C specs but in larger DO-214AA (SMB) package; 600 W P_PPM rating (vs. 400 W); higher I_FSM = 100 A.	Used where higher surge margin or board space allows larger footprint; not drop-in due to different pad layout and thermal mass.	Choose SMBJ9.0 only if system-level surge testing requires >400 W margin or existing layout accommodates SMB outline.

Compared with SMAJ9.0A, the SMAJ9.0 offers wider V_BR tolerance and slightly higher clamping voltage - advantageous for cost-sensitive, high-volume 9 V rail protection where ±12% breakdown variation is acceptable. Against SMBJ9.0, SMAJ9.0 trades surge headroom for smaller DO-214AC footprint and lower assembly cost in space-constrained adapters and lighting modules.

Availability

SMAJ9.0 is available at Aetrix Electronics and suitable for switching mode power supplies, automotive lighting control units, and industrial DC/DC converters requiring stable component supply with full traceability and lifecycle continuity.

Supply support for SMAJ9.0 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 Corporation (TSC) is a vertically integrated semiconductor manufacturer specializing in discrete power devices, TVS diodes, rectifiers, and MOSFETs for industrial, automotive, and consumer applications.

The SMAJ series is engineered specifically for high-reliability transient suppression in compact surface-mount designs, emphasizing fast response, low leakage, and automotive-grade qualification (ISO 7637-2, J-STD-020 Level 1).

FAQ

What is the maximum clamping voltage of SMAJ9.0 under a 10/1000 µs transient?

The SMAJ9.0 has a maximum clamping voltage (V_C) of 16.9 V when subjected to a 5 A peak pulse current with a 10/1000 µs waveform. This value is measured per standard test conditions (T_A = 25 °C) and defines the upper voltage limit imposed on the protected circuit during surge events. The SMAJ9.0 maintains this clamping performance across its specified operating temperature range, making it suitable for 9 V rail protection in automotive and industrial environments.

Is SMAJ9.0 unidirectional or bidirectional, and how is polarity marked?

SMAJ9.0 is a unidirectional TVS diode, with polarity indicated by a cathode band on the DO-214AC (SMA) package body. The cathode terminal connects to the protected line (e.g., 9 V rail), while the anode connects to ground. This configuration provides clamping only for positive transients relative to ground - unlike bidirectional variants (e.g., SMAJ9.0C), which suppress both polarities. The SMAJ9.0 datasheet confirms unidirectional operation and specifies cathode-band marking per JEDEC DO-214AC standards.

What is the working stand-off voltage (V_WM) and why does it matter for SMAJ9.0?

The SMAJ9.0 has a working stand-off voltage (V_WM) of 9.0 V, meaning it remains non-conductive with ≤5 µA leakage up to this DC or RMS voltage. This parameter ensures the device does not interfere with normal 9 V system operation while remaining ready to clamp transients exceeding V_BR. Selecting V_WM ≥ nominal rail voltage prevents false triggering; the SMAJ9.0's 9.0 V rating makes it ideal for 9 V supplies in adapters, lighting drivers, and DC/DC modules where margin above nominal is minimal.

Does SMAJ9.0 meet automotive transient immunity standards?

Yes, SMAJ9.0 meets ISO 7637-2 Pulse 1 (inductive load dump), Pulse 2a/2b (switching transients), and Pulse 3a/3b (supply line noise) requirements. Its 400 W peak pulse power rating, sub-1 ps response time, and validated clamping behavior under standardized waveforms make it suitable for automotive body control modules, lighting ECUs, and infotainment power supplies. TSC's official documentation explicitly lists ISO 7637-2 compliance for the SMAJ5.0–SMAJ188 family, including SMAJ9.0.

What is the moisture sensitivity level (MSL) and reflow profile guidance for SMAJ9.0?

SMAJ9.0 is rated MSL Level 1 per J-STD-020, meaning it has unlimited floor life and requires no baking prior to reflow soldering. It is qualified for standard lead-free reflow profiles (peak temperature ≤260 °C), with matte tin-plated leads meeting J-STD-002 solderability requirements. The DO-214AC package uses UL 94V-0 compliant molding compound, supporting robust thermal cycling performance in industrial and automotive applications where SMAJ9.0 is deployed.

SMAJ9.0 Specifications

Product attributes: Attribute value

Manufacturer:: Taiwan Semiconductor Corporation

Package/Case:: DO-214AC, SMA

Series:: SMAJ

Packaging:: Tape & Reel (TR)

Product Status:: Active

Type:: Zener

Unidirectional Channels:: 1

Bidirectional Channels:: -

Voltage - Reverse Standoff (Typ):: 9V

Voltage - Breakdown (Min):: 10V

Voltage - Clamping (Max) @ Ipp:: 16.9V

Current - Peak Pulse (10/1000µs):: 23.7A

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)

SMAJ9.0 FAQ

1.How can I place an order for SMAJ9.0 through Aetrix?

Please submit a Request for Quotation (RFQ) for SMAJ9.0 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 SMAJ9.0 reliable?

The price and inventory of SMAJ9.0 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ9.0 is usually 5 days.

3.What payment methods are accepted for SMAJ9.0?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ9.0 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SMAJ9.0?

SMAJ9.0 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SMAJ9.0 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 SMAJ9.0?

For technical support, including SMAJ9.0 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ9.0 requirements.

6.How does Aetrix verify that SMAJ9.0 is sourced from the original manufacturer or authorized distributors?

All SMAJ9.0 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 SMAJ9.0 meets industry standards.

7.What is the process for return or replacement of SMAJ9.0?

All SMAJ9.0 units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ9.0, 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 SMAJ9.0 part is unused and in its original packaging.

Return procedure for SMAJ9.0:

1.Submit a request within 90 days.

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

Tech Hub

2026-09-11 Comparator Circuit: Voltage Thresholds, Op-Amp Differences, LM393 and Practical Design

Comparator circuit design covering voltage thresholds, input limits, open-collector outputs, LM393 wiring, op-amp differences, hysteresis, timing, window detection and practical fault diagnosis.

2026-09-10 Schmitt Trigger Explained: Hysteresis, Circuits, Inverters and Applications

Schmitt triggers use separate rising and falling thresholds to stabilize slow or noisy signals. This guide covers hysteresis, 74HC14 and 74HCT14 selection, comparator calculations, RC oscillators and p…

2026-09-09 Counterfeit Electronic Components: How to Detect, Authenticate, and Test Suspect Parts

Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …

2026-09-08 Obsolete Electronic Components: How to Source and Evaluate Replacements

A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.

2026-09-07 TTL vs CMOS Logic Levels: 74HC and 74HCT Compatibility Explained

TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.

2026-09-04 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-02 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …