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

Taiwan Semiconductor Corporation SMAJ33

Name: SMAJ33
Brand: Taiwan Semiconductor Corporation
SKU: SMAJ33
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SMAJ33

Manufacturer:: Taiwan Semiconductor Corporation

Category:: TVS Diodes

Package:: DO-214AC, SMA

Datasheet:: SMAJ33.pdf

Description:: 400W, 40.8V, 10%, UNIDIRECTIONAL

Quantity:: RFQ Add To RFQ list

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Inventory:6,510

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Product details

Overview

SMAJ33 from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode designed for robust overvoltage protection in DC power rails and signal lines. It features a 33 V working stand-off voltage (V_WM), 36.7–44.9 V breakdown voltage (V_BR), 59.0 V maximum clamping voltage (V_C) at 6.8 A peak impulse current, and 400 W peak pulse power rating with 10/1000 µs waveform-ideal for protecting SMPS inputs and automotive DC/DC converters.

For engineers reviewing the SMAJ33 datasheet, SMAJ33 pinout, SMAJ33 application, or SMAJ33 equivalent, key selection criteria include its DO-214AC (SMA) package compatibility, bidirectional variant (SMAJ33A) availability, ISO 7637-2 Pulse 1/2a/2b/3a/3b compliance, and verified clamping performance under repetitive surge stress.

Technical Context

The SMAJ33 operates as a unidirectional avalanche diode, triggered when reverse voltage exceeds its specified V_BR range (36.7–44.9 V at 1 mA test current). Its glass-passivated junction ensures stable breakdown characteristics and low leakage (<1 µA at 33 V), while fast response time (<1.0 ps) enables effective suppression of ESD and lightning-induced transients.

Thermally rated for T_J = –55°C to +150°C and packaged in DO-214AC (SMA), the device supports automated placement and meets JESD201 Class 2 whisker resistance, UL 94V-0 flammability, and RoHS/halogen-free requirements-making it suitable for industrial and automotive-grade board-level protection.

Key Specifications

Parameter	Value and Actual Design Meaning
V_WM	33 V - Maximum continuous reverse operating voltage before clamping begins
V_BR @ I_T=1 mA	36.7–44.9 V - Verified avalanche breakdown threshold ensuring predictable turn-on
V_C @ I_PPM=6.8 A	59.0 V - Clamped voltage during 10/1000 µs surge, limiting downstream stress
P_PPM	400 W - Peak pulse power handling per single 10/1000 µs transient event
I_R @ V_WM	<1 µA - Minimal leakage current preserves efficiency in standby and low-power modes
Package	DO-214AC (SMA) - Standardized surface-mount outline enabling drop-in PCB integration

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 optimized for reflow soldering and automated assembly.

Pin/Terminal	Circuit Role	Design Meaning
Anode	Forward conduction terminal	Connected to lower-potential side (e.g., GND) in unidirectional configuration
Cathode	Reverse-biased clamping terminal	Connected to protected line (e.g., +33 V rail); marked by band on package 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 sub-nanosecond ESD events before IC damage occurs
ISO 7637-2 compliance (Pulse 1/2a/2b/3a/3b)	Validated for automotive load-dump and inductive-switching transient immunity
Moisture sensitivity level 1	Eliminates bake requirements prior to reflow, reducing manufacturing overhead

Applications

Switching Mode Power Supply (SMPS)	Automotive On-Board DC/DC Converter
Use Scenario: Input stage protection against line surges and load dump transients in AC/DC adapters and industrial SMPS units. IC Role / Device Role / Timing Role: Unidirectional TVS diode placed across input capacitor to clamp overvoltage spikes before they reach primary-side controller. Use Value: Limits peak voltage to 59.0 V during 400 W 10/1000 µs transients, preventing MOSFET gate oxide rupture and controller latch-up.	Use Scenario: Protection of 12 V or 24 V DC/DC converter inputs in automotive infotainment and ADAS modules. IC Role / Device Role / Timing Role: Standoff-rated TVS connected between battery rail and converter input to absorb ISO 7637-2 Pulse 1 (inductive switch-off) and Pulse 2b (battery disconnect). Use Value: Maintains system uptime by suppressing transients up to ±100 V without degradation, validated per automotive EMC standards.
LED Lighting Driver Input	Industrial PLC I/O Module Protection
Use Scenario: Surge protection on constant-current LED driver inputs exposed to mains-coupled transients in streetlight and commercial lighting systems. IC Role / Device Role / Timing Role: Primary-line TVS placed after bridge rectifier and before bulk capacitor to limit surge energy entering driver IC. Use Value: Withstands repeated 400 W pulses without parameter shift, extending driver lifetime in outdoor environments with high lightning exposure.	Use Scenario: Field-side protection for digital input channels in programmable logic controllers subjected to wiring-induced surges. IC Role / Device Role / Timing Role: Interface-level TVS mounted at connector entry point to shunt induced transients before signal conditioning circuitry. Use Value: Provides <1 µA leakage at 33 V, preserving input threshold accuracy while clamping to 59.0 V under 6.8 A surge.

Switching Mode Power Supply (SMPS)

Automotive On-Board DC/DC Converter

Use Scenario: Input stage protection against line surges and load dump transients in AC/DC adapters and industrial SMPS units.

IC Role / Device Role / Timing Role: Unidirectional TVS diode placed across input capacitor to clamp overvoltage spikes before they reach primary-side controller.

Use Value: Limits peak voltage to 59.0 V during 400 W 10/1000 µs transients, preventing MOSFET gate oxide rupture and controller latch-up.

Use Scenario: Protection of 12 V or 24 V DC/DC converter inputs in automotive infotainment and ADAS modules.

IC Role / Device Role / Timing Role: Standoff-rated TVS connected between battery rail and converter input to absorb ISO 7637-2 Pulse 1 (inductive switch-off) and Pulse 2b (battery disconnect).

Use Value: Maintains system uptime by suppressing transients up to ±100 V without degradation, validated per automotive EMC standards.

LED Lighting Driver Input

Industrial PLC I/O Module Protection

Use Scenario: Surge protection on constant-current LED driver inputs exposed to mains-coupled transients in streetlight and commercial lighting systems.

IC Role / Device Role / Timing Role: Primary-line TVS placed after bridge rectifier and before bulk capacitor to limit surge energy entering driver IC.

Use Value: Withstands repeated 400 W pulses without parameter shift, extending driver lifetime in outdoor environments with high lightning exposure.

Use Scenario: Field-side protection for digital input channels in programmable logic controllers subjected to wiring-induced surges.

IC Role / Device Role / Timing Role: Interface-level TVS mounted at connector entry point to shunt induced transients before signal conditioning circuitry.

Use Value: Provides <1 µA leakage at 33 V, preserving input threshold accuracy while clamping to 59.0 V under 6.8 A surge.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
SMAJ33A	Narrower V_BR range (36.7–40.6 V) and lower clamping voltage (53.3 V at 7.5 A); tighter tolerance due to A-suffix grading	Better suited for precision-clamp designs where lower V_C margin is critical, e.g., protecting 3.3 V logic with series impedance	Select SMAJ33A when clamping voltage headroom is constrained; SMAJ33 offers higher surge current margin at same V_WM
SMBJ33	Same V_WM/V_BR/V_C specs but in larger DO-214AA (SMB) package; 600 W P_PPM rating	Preferred for higher-reliability or thermally demanding layouts where PCB space allows larger footprint and enhanced thermal mass	Choose SMBJ33 for elevated ambient temperature operation (>105°C) or where derating headroom beyond 400 W is required

Compared with SMAJ33A and SMBJ33, the SMAJ33 balances compact DO-214AC packaging, industry-standard 400 W surge rating, and broad V_BR tolerance-making it optimal for cost-sensitive, space-constrained industrial and consumer power supplies requiring proven ISO 7637-2 immunity.

Availability

SMAJ33 is available at Aetrix Electronics and suitable for switching mode power supplies, automotive DC/DC converters, and LED lighting drivers requiring stable component supply with full traceability and lifecycle management.

Supply support for SMAJ33 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, serving global industrial, automotive, and consumer markets since 1979.

The SMAJ series is part of TSC's transient voltage suppressor portfolio, engineered specifically for high-reliability board-level surge protection in harsh electromagnetic environments-including automotive, industrial automation, and outdoor lighting systems.

FAQ

What is the maximum clamping voltage of SMAJ33 under standard test conditions?

The SMAJ33 has a maximum clamping voltage (V_C) of 59.0 V when subjected to a 10/1000 µs waveform with a peak impulse current (I_PPM) of 6.8 A. This value is measured per JEDEC standards and ensures downstream components see no more than 59.0 V during surge events. The SMAJ33 maintains this clamping performance across its full operating temperature range (–55°C to +150°C), making it reliable for use in thermally demanding applications.

Is SMAJ33 suitable for bidirectional transient protection?

No, SMAJ33 is a unidirectional TVS diode intended for DC line protection with defined polarity. For bidirectional applications-such as AC signal lines or differential buses-engineers must select the SMAJ33CA variant (if available) or use back-to-back SMAJ33 devices. The "A" suffix in SMAJ33A does not indicate bidirectionality; it denotes tighter V_BR tolerance. Always verify polarity marking (cathode band) during layout to ensure correct orientation of SMAJ33 in the circuit.

What is the leakage current specification for SMAJ33 at its working stand-off voltage?

The SMAJ33 exhibits a maximum reverse leakage current (I_R) of 1 µA when biased at its rated working stand-off voltage (V_WM) of 33 V, tested at 25°C. This ultra-low leakage preserves system efficiency in always-on or battery-powered applications and avoids false triggering in high-impedance sensing circuits. The SMAJ33 maintains <1 µA leakage up to 125°C, supporting operation in extended-temperature industrial environments.

Does SMAJ33 meet automotive EMC standards?

Yes, SMAJ33 is explicitly rated to meet ISO 7637-2 for automotive transient immunity, covering Pulse 1 (inductive load dump), Pulse 2a (sudden load interruption), Pulse 2b (battery disconnection), and Pulses 3a/3b (capacitive coupling and line impedance effects). Its 400 W peak pulse power rating and 59.0 V clamping voltage are validated under these waveforms, making SMAJ33 suitable for front-end protection in automotive DC/DC converters, body control modules, and infotainment power supplies.

What packaging and reel quantity is offered for SMAJ33?

SMAJ33 is supplied in DO-214AC (SMA) package format on 7,500-unit tape-and-reel carriers, compatible with standard SMT pick-and-place equipment. The package features matte tin-plated leads compliant with J-STD-002 solderability requirements and moisture sensitivity level (MSL) 1-meaning no baking is required prior to reflow. This packaging supports high-volume automated assembly while maintaining full traceability and RoHS/halogen-free compliance per IEC 61249-2-21.

SMAJ33 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):: 33V

Voltage - Breakdown (Min):: 36.7V

Voltage - Clamping (Max) @ Ipp:: 59V

Current - Peak Pulse (10/1000µs):: 6.8A

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)

SMAJ33 FAQ

1.How can I place an order for SMAJ33 through Aetrix?

Please submit a Request for Quotation (RFQ) for SMAJ33 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 SMAJ33 reliable?

The price and inventory of SMAJ33 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ33 is usually 5 days.

3.What payment methods are accepted for SMAJ33?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ33 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SMAJ33?

SMAJ33 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SMAJ33 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 SMAJ33?

For technical support, including SMAJ33 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ33 requirements.

6.How does Aetrix verify that SMAJ33 is sourced from the original manufacturer or authorized distributors?

All SMAJ33 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 SMAJ33 meets industry standards.

7.What is the process for return or replacement of SMAJ33?

All SMAJ33 units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ33, 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 SMAJ33 part is unused and in its original packaging.

Return procedure for SMAJ33:

1.Submit a request within 90 days.

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

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