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

Taiwan Semiconductor Corporation SMAJ17A

Name: SMAJ17A
Brand: Taiwan Semiconductor Corporation
SKU: SMAJ17A
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SMAJ17A

Manufacturer:: Taiwan Semiconductor Corporation

Category:: TVS Diodes

Package:: DO-214AC, SMA

Datasheet:: SMAJ17A.pdf

Description:: TVS DIODE 17VWM 27.6VC DO214AC

Quantity:: RFQ Add To RFQ list

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Inventory:7,758

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Product details

Overview

SMAJ17A from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode designed for primary-side overvoltage protection in DC power rails. It features a 17 V working stand-off voltage (V_WM), 18.9–20.9 V breakdown voltage (V_BR), 27.6 V maximum clamping voltage (V_C) at 14.5 A peak pulse current, and 400 W peak pulse power rating with 10/1000 µs waveform-used in SMPS input stages to absorb ESD and load-dump transients.

For engineers reviewing the SMAJ17A datasheet, SMAJ17A pinout, SMAJ17A application, or SMAJ17A equivalent, key selection criteria include clamping performance under ISO 7637-2 Pulse 1/2a/2b/3a/3b, unidirectional polarity marking, DO-214AC (SMA) package compatibility with automated placement, and junction temperature range of –55 °C to +150 °C for industrial-grade reliability.

Technical Context

The SMAJ17A operates as a unidirectional avalanche diode, conducting only when reverse voltage exceeds its specified V_BR range (18.9–20.9 V @ 1 mA). Its glass-passivated junction ensures stable breakdown behavior and low leakage (<1 µA @ 17 V), while fast response time (<1.0 ps) enables effective suppression of sub-nanosecond ESD events.

It is rated for 400 W peak pulse power (10/1000 µs) up to 25 °C, derating linearly above ambient temperature per Fig.2, and supports 40 A non-repetitive forward surge current (8.3 ms half-sine). The device meets JESD201 Class 2 whisker resistance and UL 94V-0 flammability requirements for PCB safety compliance.

Key Specifications

Parameter	Value and Actual Design Meaning
V_WM	17 V - Maximum continuous reverse operating voltage before conduction begins
V_BR min/max	18.9 / 20.9 V @ 1 mA - Confirmed avalanche onset range for reliable triggering margin
V_C @ I_PPM	27.6 V @ 14.5 A - Clamped voltage during 10/1000 µs transient, limiting downstream stress
P_PPM	400 W - Peak pulse power handling capability per standard waveform, critical for automotive load-dump immunity
I_R @ V_WM	<1 µA - Low leakage preserves efficiency in high-impedance bias networks
T_J range	–55 °C to +150 °C - Enables deployment in under-hood automotive or industrial power converters
Package	DO-214AC (SMA) - Standardized surface-mount outline compatible with reflow and wave soldering

Pinout & Package

DO-214AC (SMA) package: molded plastic case with matte tin-plated leads, cathode band marking polarity, 0.060 g weight, and JEDEC-compliant dimensions for automated assembly.

Pin/Terminal	Circuit Role	Design Meaning
Anode	Forward conduction terminal	Connected to lower-potential side (e.g., GND or return path) in unidirectional configuration
Cathode	Reverse-biased clamping terminal	Connected to protected line (e.g., +12 V rail); marked by band on body

Key Features

Feature	Design Value
Glass-passivated junction	Ensures stable V_BR tolerance and long-term reliability under thermal cycling
Fast response time <1.0 ps	Enables suppression of nanosecond-scale ESD events before IC damage occurs
ISO 7637-2 compliance	Validated for automotive electrical system transients including Pulse 1 (inductive switch-off), 2a/2b (battery disconnect), and 3a/3b (capacitive coupling)
Moisture sensitivity level 1	Eliminates bake requirement prior to reflow, reducing manufacturing cost and risk of popcorning
Halogen-free & RoHS compliant	Meets IEC 61249-2-21 and EU directives for environmentally restricted substances

Applications

Switching Mode Power Supply (SMPS) Input Protection	Automotive Body Control Module (BCM) Power Rail
Use Scenario: Protects AC/DC adapter front-end rectifier output against line surges and lightning-induced transients. IC Role / Device Role / Timing Role: Unidirectional TVS placed between +VOUT and GND to clamp overvoltage before it reaches downstream regulators. Use Value: Limits peak voltage to 27.6 V during 400 W transients, preventing damage to 30 V-rated MOSFETs and controllers.	Use Scenario: Shields 12 V supply rail in BCM against load dump (ISO 7637-2 Pulse 5a) and jump-start spikes. IC Role / Device Role / Timing Role: Primary clamping device on battery feed line, positioned upstream of DC/DC converter input. Use Value: Withstands 14.5 A peak impulse at 27.6 V clamping, meeting OEM requirements for 200 V/100 ms load dump immunity.
LED Driver On-Board DC/DC Converter	Industrial PLC Digital Input Protection
Use Scenario: Safeguards buck converter input in outdoor LED streetlight drivers exposed to induced surges. IC Role / Device Role / Timing Role: Standoff-rated TVS across input capacitor to absorb repetitive switching noise and external EFT bursts. Use Value: 1 µA leakage at 17 V minimizes standby power loss; DO-214AC footprint allows compact layout near connector entry point.	Use Scenario: Protects 24 V digital input circuitry in programmable logic controllers from field-wiring transients. IC Role / Device Role / Timing Role: Interface-level TVS on signal line entering optocoupler input stage. Use Value: Fast <1 ps response captures fast-rising EFT pulses (IEC 61000-4-4), while 150 °C T_J rating supports operation in sealed enclosures.

Switching Mode Power Supply (SMPS) Input Protection

Automotive Body Control Module (BCM) Power Rail

Use Scenario: Protects AC/DC adapter front-end rectifier output against line surges and lightning-induced transients.

IC Role / Device Role / Timing Role: Unidirectional TVS placed between +VOUT and GND to clamp overvoltage before it reaches downstream regulators.

Use Value: Limits peak voltage to 27.6 V during 400 W transients, preventing damage to 30 V-rated MOSFETs and controllers.

Use Scenario: Shields 12 V supply rail in BCM against load dump (ISO 7637-2 Pulse 5a) and jump-start spikes.

IC Role / Device Role / Timing Role: Primary clamping device on battery feed line, positioned upstream of DC/DC converter input.

Use Value: Withstands 14.5 A peak impulse at 27.6 V clamping, meeting OEM requirements for 200 V/100 ms load dump immunity.

LED Driver On-Board DC/DC Converter

Industrial PLC Digital Input Protection

Use Scenario: Safeguards buck converter input in outdoor LED streetlight drivers exposed to induced surges.

IC Role / Device Role / Timing Role: Standoff-rated TVS across input capacitor to absorb repetitive switching noise and external EFT bursts.

Use Value: 1 µA leakage at 17 V minimizes standby power loss; DO-214AC footprint allows compact layout near connector entry point.

Use Scenario: Protects 24 V digital input circuitry in programmable logic controllers from field-wiring transients.

IC Role / Device Role / Timing Role: Interface-level TVS on signal line entering optocoupler input stage.

Use Value: Fast <1 ps response captures fast-rising EFT pulses (IEC 61000-4-4), while 150 °C T_J rating supports operation in sealed enclosures.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
SMAJ17CA	Bidirectional variant; symmetric V_BR (18.9–20.9 V) in both polarities; same V_C and P_PPM	Required where AC-coupled or floating lines need protection in both directions (e.g., RS-485 data lines)	Select SMAJ17CA only if bidirectional clamping is required; SMAJ17A is optimal for DC rail protection with polarity-defined placement.
SMBJ17A	Same electrical specs but in larger DO-214AA (SMB) package; 600 W P_PPM rating (vs. 400 W)	Used where higher surge margin or legacy board layout requires SMB footprint	SMBJ17A offers greater power headroom but occupies ~30% more PCB area; choose SMAJ17A for space-constrained designs needing 400 W compliance.

Compared with SMAJ17CA and SMBJ17A, the SMAJ17A delivers optimized unidirectional clamping in the smallest standardized surface-mount TVS package, balancing surge robustness, board space, and automated assembly compatibility for DC power rail protection.

Availability

SMAJ17A is available at Aetrix Electronics and suitable for switching mode power supplies, automotive body control modules, and industrial PLC input circuits requiring stable component supply with full traceability and lifecycle management.

Supply support for SMAJ17A 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 analog and discrete semiconductor manufacturer headquartered in Hsinchu, Taiwan, specializing in power management, protection, and signal conditioning devices.

The SMAJ series is part of TSC's transient voltage suppressor product line, engineered specifically for high-reliability DC power rail protection in automotive, industrial, and consumer power electronics where compact size and ISO 7637-2 compliance are mandatory.

FAQ

What is the clamping voltage of the SMAJ17A under peak pulse conditions?

The SMAJ17A has a maximum clamping voltage (V_C) of 27.6 V when subjected to its rated peak pulse current of 14.5 A using the 10/1000 µs waveform. This value is measured per standard test conditions (TA = 25 °C) and defines the upper voltage limit imposed on protected circuitry during transient events. Designers use this parameter to verify that downstream components remain within their absolute maximum voltage ratings during surge conditions. The SMAJ17A maintains this clamping performance across its full operating temperature range.

Is the SMAJ17A suitable for automotive applications requiring ISO 7637-2 compliance?

Yes, the SMAJ17A is explicitly rated to meet ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b test requirements, making it suitable for automotive power rail protection including body control modules and infotainment power supplies. Its 400 W peak pulse power rating, fast <1.0 ps response time, and –55 °C to +150 °C junction temperature range align with OEM stress-test specifications. The SMAJ17A's DO-214AC package also supports automated placement in high-volume automotive PCB assembly. Always validate final layout per vehicle-specific EMC test plans.

How does the SMAJ17A differ from the SMAJ17 (non-A) variant?

The SMAJ17A features a tighter breakdown voltage tolerance (18.9–20.9 V) compared to the SMAJ17 (18.9–23.1 V), resulting in more consistent clamping onset and reduced variation in protected circuit stress levels. Both share identical package (DO-214AC), power rating (400 W), and thermal specifications. The "A" suffix denotes improved V_BR uniformity, which enhances design margin predictability in precision power rail protection. For new designs, SMAJ17A is preferred where tighter parametric control is required.

What is the maximum reverse leakage current specification for the SMAJ17A?

The SMAJ17A specifies a maximum reverse leakage current (I_R) of 1 µA when biased at its working stand-off voltage of 17 V, tested at TA = 25 °C. This low leakage ensures minimal power loss in always-on systems and avoids false triggering in high-impedance sensing nodes. Leakage remains below 5 µA up to 85 °C ambient, supporting reliable operation in thermally demanding environments. The SMAJ17A's glass-passivated junction contributes directly to this stable leakage performance across temperature and lifetime.

Can the SMAJ17A be used in bidirectional signal line protection?

No, the SMAJ17A is a unidirectional TVS diode and must be used with correct polarity-cathode toward the protected line-to function properly. For bidirectional signal lines such as RS-485, CAN, or USB data pairs, the SMAJ17CA (bidirectional variant) is required. Using SMAJ17A on AC-coupled or floating signals risks failure to clamp negative transients and may cause permanent damage. Always match device polarity to the signal topology: SMAJ17A for DC rails with defined ground reference, SMAJ17CA for differential or AC-coupled paths.

SMAJ17A 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):: 17V

Voltage - Breakdown (Min):: 18.9V

Voltage - Clamping (Max) @ Ipp:: 27.6V

Current - Peak Pulse (10/1000µs):: 14.5A

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)

SMAJ17A FAQ

1.How can I place an order for SMAJ17A through Aetrix?

Please submit a Request for Quotation (RFQ) for SMAJ17A 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 SMAJ17A reliable?

The price and inventory of SMAJ17A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ17A is usually 5 days.

3.What payment methods are accepted for SMAJ17A?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ17A transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SMAJ17A?

SMAJ17A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SMAJ17A 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 SMAJ17A?

For technical support, including SMAJ17A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ17A requirements.

6.How does Aetrix verify that SMAJ17A is sourced from the original manufacturer or authorized distributors?

All SMAJ17A 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 SMAJ17A meets industry standards.

7.What is the process for return or replacement of SMAJ17A?

All SMAJ17A units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ17A, 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 SMAJ17A part is unused and in its original packaging.

Return procedure for SMAJ17A:

1.Submit a request within 90 days.

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

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