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Taiwan Semiconductor Corporation SMAJ15
- Part No.:
- SMAJ15
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ15.pdf
- Description:
- 400W, 18.6V, 10%, UNIDIRECTIONAL
- Quantity:
- Payment:
- Shipping:
Inventory:8,570
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Product details
Overview
SMAJ15 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 15 V working stand-off voltage (VWM), 16.7–20.4 V breakdown voltage (VBR) at 1 mA test current, and clamps to ≤26.9 V at 14.9 A peak impulse current under 10/1000 µs waveform - delivering 400 W peak pulse power for automotive and industrial power supply protection.
For engineers reviewing the SMAJ15 datasheet, SMAJ15 pinout, SMAJ15 application, or SMAJ15 equivalent, key selection criteria include its unidirectional polarity, 1 µA max reverse leakage at 15 V, -55°C to +150°C operating junction temperature, ISO 7637-2 Pulse 1/2a/2b/3a/3b compliance, and suitability for automated SMT placement in high-reliability DC/DC converters and adapters.
Technical Context
The SMAJ15 operates as a unidirectional avalanche diode, triggered when reverse voltage exceeds its specified VBR range (16.7–20.4 V). Its glass-passivated junction ensures stable breakdown behavior and low leakage (<1 µA at VWM), while sub-1 ps response time enables effective suppression of ESD and load-dump transients before sensitive downstream circuitry is damaged.
It is rated for 400 W peak pulse power (10/1000 µs), derated linearly above 25°C ambient per Fig.2, with steady-state power dissipation limited to 1 W. The device meets JESD201 Class 2 whisker resistance and UL 94V-0 flammability requirements, supporting robust deployment in automotive-grade and industrial power modules.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 15 V - maximum continuous reverse voltage before conduction begins; defines safe operating margin in 12 V nominal systems. |
| VBR min/max | 16.7 V / 20.4 V at 1 mA - guaranteed avalanche initiation window; ensures consistent clamping across production lots. |
| VC @ IPPM | ≤26.9 V at 14.9 A - clamped voltage during 10/1000 µs surge; limits stress on protected ICs like PMICs or microcontrollers. |
| PPPM | 400 W (10/1000 µs) - peak transient energy handling capacity; sufficient for ISO 7637-2 Pulse 2b (load dump) in 12 V vehicle networks. |
| IR @ VWM | ≤1 µA - ultra-low reverse leakage at stand-off voltage; prevents parasitic drain in battery-backed or low-power circuits. |
| TJ max | +150 °C - maximum junction temperature; supports operation in under-hood automotive environments and enclosed industrial enclosures. |
| Package | DO-214AC (SMA) - industry-standard surface-mount outline with cathode band marking; compatible with standard reflow profiles and AOI inspection. |
Pinout & Package
DO-214AC (SMA) package: molded plastic case with matte tin-plated leads, cathode indicated by a band on the body. Leads are solderable per J-STD-002; polarity must be observed during PCB layout to ensure correct unidirectional clamping orientation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to ground or low-voltage rail; forms return path during transient clamp event. |
| Cathode | High-side input terminal | Connected to protected line (e.g., 12 V rail); conducts avalanche current when voltage exceeds VBR. |
Key Features
| Feature | Design Value |
|---|---|
| Glass passivated junction | Ensures stable, repeatable breakdown voltage and long-term reliability under thermal cycling and humidity exposure. |
| Fast response time <1 ps | Enables clamping before transient energy couples into downstream logic or analog circuitry - critical for protecting CAN transceivers and MCU I/O. |
| ISO 7637-2 compliance | Validated for Pulse 1 (inductive switch-off), Pulse 2a/2b (battery disconnect/load dump), and Pulse 3a/3b (capacitive coupling), meeting automotive OEM requirements. |
| Moisture sensitivity level 1 | Zero bake requirement prior to reflow; simplifies manufacturing flow and reduces risk of popcorning during assembly. |
| Halogen-free & RoHS compliant | Meets IEC 61249-2-21 and EU RoHS Directive 2011/65/EU - required for export to EU, China, and other regulated markets. |
Applications
| Switching Mode Power Supply (SMPS) | Automotive On-Board DC/DC Converter |
|---|---|
Use Scenario: Protection of primary-side MOSFET gate drivers and secondary-side synchronous rectifiers against switching-induced voltage spikes and cross-talk. IC Role / Device Role / Timing Role: Unidirectional TVS placed across input bus or output rail to clamp overshoots exceeding 15 V stand-off threshold. Use Value: Prevents cumulative gate oxide damage and latch-up in power ICs by limiting transient voltage to ≤26.9 V during 400 W surges. | Use Scenario: Input rail protection in 12 V-to-3.3 V/5 V DC/DC modules used in ADAS camera modules and infotainment head units. IC Role / Device Role / Timing Role: Standoff-clamp TVS on 12 V input to absorb load-dump transients (Pulse 2b) up to 35 V for 400 ms without failure. Use Value: Maintains system uptime by preventing brownout resets or permanent damage to buck controller ICs during vehicle battery disconnection events. |
| Industrial Adapter Input Stage | LED Driver Power Input |
Use Scenario: Surge protection on AC/DC adapter outputs feeding PLC I/O modules or sensor signal conditioners. IC Role / Device Role / Timing Role: Unidirectional clamping device placed between rectified DC output and downstream filter capacitor to limit overvoltage from line transients. Use Value: Extends MTBF by eliminating premature electrolytic capacitor degradation caused by repeated 26.9 V clamping events. | Use Scenario: Input protection for constant-current LED drivers in streetlight and architectural lighting systems exposed to lightning-induced surges. IC Role / Device Role / Timing Role: Primary-line TVS suppressing induced surges from nearby AC mains switching or indirect lightning strikes on outdoor wiring. Use Value: Ensures driver IC survival during 1 kV/0.5 µs common-mode surges by clamping within 1 ps and dissipating 400 W peak energy. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ15A | Narrower VBR range (16.7–18.5 V) and lower clamping voltage (24.4 V at 16.4 A); tighter tolerance improves predictability in precision clamping designs. | Better suited for systems requiring tighter voltage margins around 15 V rails, such as low-dropout LDO inputs or USB PD power paths. | Select SMAJ15A when clamping consistency and reduced VC are prioritized over absolute peak current rating. |
| P6SMB15A | Same DO-214AA package (slightly smaller than DO-214AC), 15 V VWM, but rated for 600 W peak power (10/1000 µs); higher IPPM (38.9 A) and VC (24.4 V). | Preferred in higher-energy surge environments (e.g., telecom power feeds) where 600 W capability provides additional safety margin beyond ISO 7637-2 requirements. | Choose P6SMB15A only if board space allows DO-214AA footprint and system-level testing confirms need for >400 W rating. |
Compared with SMAJ15, SMAJ15A offers tighter VBR control and lower clamping voltage at the cost of slightly reduced peak current handling, while P6SMB15A delivers higher surge capacity in a physically smaller package - making SMAJ15 the balanced choice for cost-sensitive, ISO-compliant automotive and industrial DC/DC applications.
Availability
SMAJ15 is available at Aetrix Electronics and suitable for switching mode power supplies, automotive DC/DC converters, and industrial adapters requiring stable component supply, full traceability, and long-term lifecycle support.
Supply support for SMAJ15 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 automotive, industrial, and consumer applications.
The SMAJ series was developed specifically for surface-mount transient suppression in harsh electromagnetic environments - emphasizing fast response, high reliability, and compliance with automotive EMC standards including ISO 7637-2.
FAQ
What is the polarity configuration of the SMAJ15?
The SMAJ15 is a unidirectional TVS diode, with cathode marked by a band on the DO-214AC package body. It conducts only when reverse-biased beyond its breakdown voltage (16.7–20.4 V), making it suitable for DC line protection where polarity is fixed - unlike bidirectional variants (e.g., SMAJ15CA) used in AC-coupled or differential signal paths. This polarity must be correctly oriented during PCB layout to ensure proper clamping function in the SMAJ15 application.
Does the SMAJ15 meet automotive qualification standards?
Yes, the SMAJ15 meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b test requirements for transient immunity in 12 V vehicle electrical systems. It is not AEC-Q200 qualified as a standalone component, but its construction - including glass-passivated junction, JESD201 Class 2 whisker resistance, and -55°C to +150°C operating range - aligns with automotive-grade reliability expectations. System-level validation per ISO 16750-2 remains the responsibility of the end designer using the SMAJ15.
What is the maximum clamping voltage of the SMAJ15 under surge conditions?
The SMAJ15 has a maximum clamping voltage (VC) of 26.9 V when subjected to its rated peak impulse current (IPPM) of 14.9 A under the standardized 10/1000 µs waveform. This value is measured at the device terminals and represents the upper bound of voltage seen by downstream circuitry during worst-case transient events - a critical parameter for ensuring compatibility with 3.3 V or 5 V logic interfaces protected by the SMAJ15.
Can the SMAJ15 be used in bidirectional signal lines?
No, the SMAJ15 is strictly unidirectional and must not be used on bidirectional or AC-coupled signal lines. For such applications, Taiwan Semiconductor offers the SMAJ15CA variant (bidirectional, same VWM), which provides symmetrical clamping in both polarities. Using the SMAJ15 in reverse-biased signal paths risks forward conduction and unintended loading - always verify polarity and signal swing range before selecting the SMAJ15 for any circuit node.
What is the moisture sensitivity level (MSL) of the SMAJ15 and how does it affect assembly?
The SMAJ15 has a moisture sensitivity level (MSL) of Level 1 per J-STD-020, meaning it may be stored indefinitely at ≤30°C/60% RH without baking prior to reflow soldering. This eliminates pre-bake steps in SMT assembly, reduces process complexity, and avoids thermal stress on the device - a key advantage for high-volume manufacturing of power supplies and adapters where the SMAJ15 is commonly deployed.
SMAJ15 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):
- 15V
- Voltage - Breakdown (Min):
- 16.7V
- Voltage - Clamping (Max) @ Ipp:
- 26.9V
- Current - Peak Pulse (10/1000µs):
- 14.9A
- 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)
SMAJ15 FAQ
1.How can I place an order for SMAJ15 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ15 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 SMAJ15 reliable?
The price and inventory of SMAJ15 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ15 is usually 5 days.
3.What payment methods are accepted for SMAJ15?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ15 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ15?
SMAJ15 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ15 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 SMAJ15?
For technical support, including SMAJ15 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ15 requirements.
6.How does Aetrix verify that SMAJ15 is sourced from the original manufacturer or authorized distributors?
All SMAJ15 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 SMAJ15 meets industry standards.
7.What is the process for return or replacement of SMAJ15?
All SMAJ15 units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ15, 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 SMAJ15 part is unused and in its original packaging.
Return procedure for SMAJ15:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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