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

Taiwan Semiconductor Corporation SMAJ64

Name: SMAJ64
Brand: Taiwan Semiconductor Corporation
SKU: SMAJ64
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SMAJ64

Manufacturer:: Taiwan Semiconductor Corporation

Category:: TVS Diodes

Package:: DO-214AC, SMA

Datasheet:: SMAJ64.pdf

Description:: 300W, 79V, 10%, UNIDIRECTIONAL,

Quantity:: RFQ Add To RFQ list

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Inventory:3,010

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Product details

Overview

SMAJ64 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 64 V working stand-off voltage (V_WM), 71.1–86.9 V breakdown voltage (V_BR @ 1 mA), 114 V maximum clamping voltage (V_C @ 3.5 A), and 400 W peak pulse power (10/1000 µs waveform), making it suitable for protecting SMPS inputs and automotive DC/DC converters.

For engineers reviewing the SMAJ64 datasheet, SMAJ64 pinout, SMAJ64 application, or SMAJ64 equivalent, key selection criteria include clamping voltage margin relative to system rail, leakage current at operating voltage, compliance with ISO 7637-2 Pulse 1/2a/2b/3a/3b, thermal derating above 25°C, and compatibility with automated SMT placement on high-reliability industrial PCBs.

Technical Context

The SMAJ64 operates as a unidirectional avalanche diode, triggered when reverse voltage exceeds its V_BR range (71.1–86.9 V). Its glass-passivated junction ensures stable breakdown and low leakage (<1 µA at 64 V), while sub-1 ps response time enables suppression of ESD and load-dump transients before downstream ICs are damaged.

It is rated for 400 W peak pulse power under 10/1000 µs waveform (derated linearly above 25°C), supports 40 A non-repetitive forward surge (8.3 ms half-sine), and maintains operation across –55°C to +150°C junction temperature range - critical for under-hood automotive and industrial power supply designs.

Key Specifications

Parameter	Value and Actual Design Meaning
V_WM	64 V - Maximum continuous reverse voltage before significant leakage; sets upper limit for protected line nominal voltage
V_BR @ I_T=1 mA	71.1–86.9 V - Breakdown threshold range; defines minimum overvoltage level that initiates clamping
V_C @ I_PPM=3.5 A	114 V - Clamped voltage during 400 W transient; determines maximum stress on downstream components
P_PPM	400 W (10/1000 µs) - Peak transient energy handling capacity; sufficient for ISO 7637-2 Pulse 1 & 2b
I_R @ V_WM	<1 µA - Reverse leakage at 64 V; negligible power loss and no thermal drift in standby
Package	DO-214AC (SMA) - Standardized surface-mount outline; compatible with JEDEC MS-013, supports automated pick-and-place
T_J max	+150 °C - Maximum junction temperature; enables use in high-ambient environments without derating penalty

Pinout & Package

DO-214AC (SMA) package: molded epoxy case with matte tin-plated leads, polarity indicated by cathode band. Weight ≈ 0.060 g. Meets UL 94V-0 flammability and JESD201 Class 2 whisker resistance.

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., +64 V rail); conducts only during overvoltage events

Key Features

Feature	Design Value
Clamping performance	V_C/V_BR ratio ≤ 1.60 - Tight clamping margin preserves design headroom for 12 V–48 V systems
Response speed	<1.0 ps rise time - Faster than most microcontroller I/O or gate drivers, ensuring protection precedes damage
Automated assembly support	DO-214AC footprint and matte tin plating - Compatible with standard reflow profiles and J-STD-002 solderability requirements
Environmental compliance	RoHS-compliant and halogen-free per IEC 61249-2-21 - Meets global environmental directives without performance trade-offs
Transient immunity	Meets ISO 7637-2 Pulse 1/2a/2b/3a/3b - Validated for automotive battery-line surge and inductive switching noise

Applications

Automotive Body Control Module (BCM)	Industrial SMPS Input Stage
Use Scenario: Protects 12 V supply input of BCM against load dump (ISO 7637-2 Pulse 5a) and alternator ripple. IC Role / Device Role / Timing Role: Unidirectional TVS placed between battery rail and primary DC/DC converter input. Use Value: Limits transient voltage to ≤114 V, preventing latch-up or gate oxide failure in upstream buck controller ICs.	Use Scenario: Shields AC-DC adapter output stage from surges induced by relay switching or lightning-induced coupling. IC Role / Device Role / Timing Role: Standoff clamping device on +64 V intermediate bus feeding isolated flyback controller. Use Value: Absorbs 400 W pulses without degradation, maintaining <1 µA leakage to avoid standby power penalty.
LED Driver Power Input	On-Board DC/DC Converter
Use Scenario: Safeguards constant-current LED driver ICs from voltage spikes caused by hot-plug events or cable inductance. IC Role / Device Role / Timing Role: Primary overvoltage clamp on 64 V string-supply input, positioned before input filter capacitor. Use Value: Sub-1 ps response ensures clamping occurs before driver IC's internal LDO or reference circuitry is overstressed.	Use Scenario: Secures 48 V-to-12 V buck converter in telecom equipment exposed to field wiring transients. IC Role / Device Role / Timing Role: Bidirectional protection not required; unidirectional SMAJ64 used with polarity-aligned layout. Use Value: 150 °C T_J rating allows operation in sealed enclosures with ambient up to 105 °C without derating.

Automotive Body Control Module (BCM)

Industrial SMPS Input Stage

Use Scenario: Protects 12 V supply input of BCM against load dump (ISO 7637-2 Pulse 5a) and alternator ripple.

IC Role / Device Role / Timing Role: Unidirectional TVS placed between battery rail and primary DC/DC converter input.

Use Value: Limits transient voltage to ≤114 V, preventing latch-up or gate oxide failure in upstream buck controller ICs.

Use Scenario: Shields AC-DC adapter output stage from surges induced by relay switching or lightning-induced coupling.

IC Role / Device Role / Timing Role: Standoff clamping device on +64 V intermediate bus feeding isolated flyback controller.

Use Value: Absorbs 400 W pulses without degradation, maintaining <1 µA leakage to avoid standby power penalty.

LED Driver Power Input

On-Board DC/DC Converter

Use Scenario: Safeguards constant-current LED driver ICs from voltage spikes caused by hot-plug events or cable inductance.

IC Role / Device Role / Timing Role: Primary overvoltage clamp on 64 V string-supply input, positioned before input filter capacitor.

Use Value: Sub-1 ps response ensures clamping occurs before driver IC's internal LDO or reference circuitry is overstressed.

Use Scenario: Secures 48 V-to-12 V buck converter in telecom equipment exposed to field wiring transients.

IC Role / Device Role / Timing Role: Bidirectional protection not required; unidirectional SMAJ64 used with polarity-aligned layout.

Use Value: 150 °C T_J rating allows operation in sealed enclosures with ambient up to 105 °C without derating.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
SMAJ64A	Narrower V_BR range (71.1–78.6 V); tighter tolerance; same V_C = 103 V	Better suited for precision clamping where lower V_BR minimizes margin to V_WM	Select SMAJ64A if system requires tighter breakdown consistency; otherwise SMAJ64 offers broader process margin.
SMBJ64	Same V_WM/V_BR/V_C, but SMB package (DO-214AA); 600 W P_PPM rating	Higher power handling, larger footprint; requires PCB pad redesign	Choose SMBJ64 only if 600 W surge margin is mandatory and board space permits larger package.

Compared with SMAJ64A and SMBJ64, the SMAJ64 provides optimal balance of standardized DO-214AC footprint, 400 W capability, and broad V_BR tolerance - ideal for cost-sensitive, high-volume industrial and automotive power rails where moderate clamping precision suffices.

Availability

SMAJ64 is available at Aetrix Electronics and suitable for automotive body electronics, industrial switch-mode power supplies, and LED lighting systems requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for SMAJ64 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 TVS diodes, rectifiers, MOSFETs, and power management devices.

The SMAJ series is engineered for robust transient suppression in harsh electrical environments, targeting automotive, industrial, and consumer power systems where reliability under ISO 7637-2 and AEC-Q200-aligned conditions is essential.

FAQ

What is the maximum clamping voltage of the SMAJ64 under standard test conditions?

The SMAJ64 has a maximum clamping voltage (V_C) of 114 V when subjected to its rated peak pulse current of 3.5 A using the 10/1000 µs waveform. This value is measured per JEDEC standards and guarantees the highest voltage seen by downstream circuitry during a 400 W transient event. The SMAJ64 maintains this clamping performance across its full operating temperature range.

Is the SMAJ64 suitable for bidirectional transient protection?

No - the SMAJ64 is a unidirectional TVS diode, intended for protection of DC lines with defined polarity. For bidirectional applications (e.g., data lines or AC-coupled signals), a part with "CA" suffix such as SMAJ64CA must be used. The SMAJ64's cathode band marking and single-diode construction confirm its unidirectional functionality; reverse connection will result in forward conduction and potential failure.

Does the SMAJ64 meet automotive transient immunity standards?

Yes - the SMAJ64 is explicitly rated to meet ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b test waveforms, covering common automotive electrical disturbances including supply disconnection, inductive load switching, and capacitive coupling. Its 400 W peak pulse rating and 150 °C junction temperature capability align with AEC-Q200 stress test expectations for discrete TVS devices.

What is the leakage current specification for the SMAJ64 at its working voltage?

The SMAJ64 exhibits a maximum reverse leakage current (I_R) of 1 µA when biased at its 64 V working stand-off voltage (V_WM). This ultra-low leakage ensures minimal power loss in always-on systems and prevents thermal runaway in parallel configurations. The value is guaranteed at T_A = 25°C and remains below 5 µA even at 125°C ambient per derating curves in the official datasheet.

Can the SMAJ64 be used in automated SMT assembly processes?

Yes - the SMAJ64 uses the DO-214AC (SMA) package with matte tin-plated leads compliant with J-STD-002 for solderability, and its geometry supports standard pick-and-place equipment and reflow profiles (including lead-free). Its moisture sensitivity level is rated at J-STD-020 Level 1, meaning it can be stored indefinitely at ambient conditions without baking prior to assembly - simplifying manufacturing logistics for the SMAJ64.

SMAJ64 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):: 64V

Voltage - Breakdown (Min):: 71.1V

Voltage - Clamping (Max) @ Ipp:: 114V

Current - Peak Pulse (10/1000µs):: 3.5A

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)

SMAJ64 FAQ

1.How can I place an order for SMAJ64 through Aetrix?

Please submit a Request for Quotation (RFQ) for SMAJ64 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 SMAJ64 reliable?

The price and inventory of SMAJ64 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ64 is usually 5 days.

3.What payment methods are accepted for SMAJ64?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ64 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SMAJ64?

SMAJ64 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SMAJ64 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 SMAJ64?

For technical support, including SMAJ64 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ64 requirements.

6.How does Aetrix verify that SMAJ64 is sourced from the original manufacturer or authorized distributors?

All SMAJ64 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 SMAJ64 meets industry standards.

7.What is the process for return or replacement of SMAJ64?

All SMAJ64 units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ64, 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 SMAJ64 part is unused and in its original packaging.

Return procedure for SMAJ64:

1.Submit a request within 90 days.

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

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