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Alpha & Omega Semiconductor Inc. SMDJ12A
- Part No.:
- SMDJ12A
- Manufacturer:
- Alpha & Omega Semiconductor Inc.
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SMDJ12A.pdf
- Description:
- 1CH 12V UNIDIRECTIONAL 3000W SMD
- Quantity:
- Payment:
- Shipping:
Inventory:5,734
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Product details
Overview
SMDJ12A from Alpha & Omega Semiconductor is a unidirectional transient voltage suppressor diode (TVS) designed for robust overvoltage protection in DC power rails and signal lines. It features a 12.0 V reverse stand-off voltage (VRWM), 13.3–14.7 V breakdown voltage (VBR) at 1 mA, 19.9 V maximum clamping voltage (VC) at 150.8 A peak pulse current, and 3000 W peak pulse power dissipation on a 10/1000 µs waveform - deployed in industrial motor drives and telecom power supplies.
For engineers reviewing the SMDJ12A datasheet, pinout, applications, or equivalent options, key selection criteria include clamping performance under 150 A surge, thermal resistance (RθJA = 75 °C/W), unidirectional polarity with cathode band marking, and DO-214AB package compatibility with high-density PCB layouts.
Technical Context
The SMDJ12A operates as a silicon avalanche diode optimized for fast transient suppression. Its glass-passivated junction enables sub-nanosecond response time (<1.0 ps), while its low-profile DO-214AB package supports surface-mount assembly and meets MSL Level 1 reflow requirements (260 °C peak).
Designed for single-polarity DC protection, it delivers stable clamping with a temperature coefficient of ΔVBR = 0.1% × VBR per °C change from 25 °C, and sustains repetitive surges at ≤0.01% duty cycle when mounted on 8.0 mm × 8.0 mm copper pads.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 12.0 V - Maximum continuous reverse operating voltage before clamping begins |
| VBR @ IT=1 mA | 13.3–14.7 V - Confirmed avalanche conduction threshold under standardized test current |
| VC @ IPPM | 19.9 V - Clamped voltage during 150.8 A 10/1000 µs surge, defining protected circuit stress level |
| PPPM | 3000 W - Peak transient energy handling capacity on standard lightning/surge waveform |
| TJ max | +150 °C - Maximum junction temperature enabling operation in high-ambient industrial environments |
| RθJA | 75 °C/W - Thermal resistance to ambient, guiding heatsinking requirements on standard FR-4 PCB |
| IR @ VRWM | 2.0 µA - Reverse leakage at rated stand-off, ensuring minimal standby power loss |
Pinout & Package
DO-214AB (SMC J-Bend) surface-mount package with molded plastic case, matte tin lead-free plating, and cathode indicated by a color band on the unidirectional SMDJ12A.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry point during forward conduction | Connected to lower-potential side of protected line; not used in normal TVS operation |
| Cathode (banded end) | Clamping node for reverse transients | Connected to higher-potential rail (e.g., +12 V supply); conducts avalanche current to ground during overvoltage |
Key Features
| Feature | Design Value |
|---|---|
| Fast response time | <1.0 ps - Enables suppression of ESD and fast-rising lightning-induced transients before IC damage occurs |
| Glass-passivated junction | Enhanced reliability and stable VBR over lifetime vs. non-passivated alternatives |
| MSL Level 1 rating | Compatible with standard Pb-free reflow profiles up to 260 °C peak without moisture-induced failure |
| UL 94V-0 flammability | Self-extinguishing plastic housing meeting safety standards for enclosed power systems |
| Built-in strain relief | Reduces mechanical stress at solder joints during thermal cycling or board flexure |
Applications
| Industrial Motor Drives | Telecom Power Supplies |
|---|---|
Use Scenario: Protection of 12 V control logic inputs against back-EMF spikes from relay coils and H-bridge switching. IC Role / Device Role: Unidirectional TVS placed between microcontroller I/O pin and chassis ground. Use Value: Limits transient voltage to ≤19.9 V during 150 A surges, preventing latch-up or gate oxide rupture in 3.3 V/5 V logic interfaces. | Use Scenario: Input-stage surge protection on 12 V DC-DC converter front-end exposed to PoE or battery backup lines. IC Role / Device Role: Primary clamping device across input rail and ground, upstream of EMI filter. Use Value: Absorbs 3000 W transient energy without degradation, maintaining system uptime during AC-line coupling events. |
| Automotive Body Control Modules | Programmable Logic Controllers |
Use Scenario: Guarding LIN bus transceivers and sensor supply lines against load-dump and jump-start transients. IC Role / Device Role: Unidirectional TVS connected from 12 V sensor rail to ground, adjacent to connector interface. Use Value: Withstands 300 A peak forward surge (IFSM = 300 A, 8.3 ms) and clamps within spec across -40 °C to +125 °C operating range. | Use Scenario: Protecting 24 V digital I/O modules from field-wiring induced surges in factory automation cabinets. IC Role / Device Role: Rail-to-ground TVS on PLC input/output terminal blocks. Use Value: Delivers repeatable clamping performance at 0.01% duty cycle, supporting long-term reliability in cyclic industrial environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SAC12 | Lower PPPM (1500 W), higher VC (23.2 V at 100 A), same DO-214AB package | Less robust clamping margin for 12 V systems under high-current surges | Select when cost sensitivity outweighs need for 3000 W surge headroom |
| SMCJ12A | Identical electrical specs and DO-214AB footprint; manufactured by Vishay with same VRWM/VBR/VC ratings | No functional or layout impact; validated alternative for dual-sourcing | Choose for supply chain diversification without design revision |
Compared with SAC12 and SMCJ12A, the SMDJ12A provides superior 3000 W surge capability and tighter 13.3–14.7 V VBR tolerance, making it preferred for mission-critical 12 V rail protection where clamping consistency and energy absorption are prioritized.
Availability
SMDJ12A is available at Aetrix Electronics and suitable for industrial motor drives, telecom power supplies, and automotive body control modules requiring stable component supply and long-lifecycle support.
Supply support for SMDJ12A 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
Alpha & Omega Semiconductor (AOS) is a fabless power semiconductor company specializing in MOSFETs, TVS diodes, and power ICs for efficiency-critical applications.
The SMDJ series is engineered for high-energy transient suppression in harsh environments, targeting industrial, telecom, and automotive power systems where reliability under repeated surge stress is mandatory.
FAQ
What is the clamping voltage of the SMDJ12A under maximum rated surge current?
The SMDJ12A exhibits a maximum clamping voltage (VC) of 19.9 V when subjected to its rated peak pulse current (IPPM) of 150.8 A on a 10/1000 µs waveform. This value defines the upper voltage limit imposed on the protected circuit during transient events and is measured with the device mounted on 8.0 mm × 8.0 mm copper pads per terminal, as specified in the AOS datasheet Rev. 1.2.
Is the SMDJ12A suitable for bidirectional transient protection?
No, the SMDJ12A is a unidirectional TVS diode, identified by the "A" suffix and marked with a cathode band. For bidirectional operation, the SMDJ12CA variant must be used - it provides symmetrical clamping in both polarities and is marked with "DEE" code. The SMDJ12A's internal structure and polarity marking confirm its single-direction functionality.
What is the thermal resistance of the SMDJ12A, and how does it affect PCB layout?
The SMDJ12A has a typical junction-to-ambient thermal resistance (RθJA) of 75 °C/W when mounted on standard FR-4 with no additional copper. To maintain TJ ≤ 150 °C under sustained surge conditions, PCB layout must include ≥8.0 mm × 8.0 mm copper pads per terminal, as specified in the datasheet - this reduces RθJA and prevents thermal runaway during repetitive transients.
Does the SMDJ12A meet RoHS and halogen-free compliance standards?
Yes, the SMDJ12A is an AOS Green Product: it is Pb-free, RoHS compliant, and halogen-free per AOS' Green Policy. This is confirmed in the datasheet Rev. 1.2 (Page 4), which states all AOS Green Products use reduced halogen levels and comply with EU RoHS Directive 2011/65/EU and related amendments.
What is the maximum surge current the SMDJ12A can withstand without degradation?
The SMDJ12A is rated for a peak pulse current (IPPM) of 150.8 A on a 10/1000 µs waveform and a non-repetitive forward surge current (IFSM) of 300 A for an 8.3 ms half-sine wave. These values are validated under JEDEC test conditions and define the absolute limits for single-event robustness; exceeding them risks permanent parametric shift or catastrophic failure of the SMDJ12A.
SMDJ12A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Alpha & Omega Semiconductor Inc.
- Package/Case:
- DO-214AB, SMC
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 12V
- Voltage - Breakdown (Min):
- 13.3V
- Voltage - Clamping (Max) @ Ipp:
- 19.9V
- Current - Peak Pulse (10/1000µs):
- 150.8A
- Power - Peak Pulse:
- 3000W (3kW)
- 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-214AB
SMDJ12A FAQ
1.How can I place an order for SMDJ12A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMDJ12A 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 SMDJ12A reliable?
The price and inventory of SMDJ12A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMDJ12A is usually 5 days.
3.What payment methods are accepted for SMDJ12A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMDJ12A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMDJ12A?
SMDJ12A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMDJ12A 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 SMDJ12A?
For technical support, including SMDJ12A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMDJ12A requirements.
6.How does Aetrix verify that SMDJ12A is sourced from the original manufacturer or authorized distributors?
All SMDJ12A 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 SMDJ12A meets industry standards.
7.What is the process for return or replacement of SMDJ12A?
All SMDJ12A units undergo pre-shipment inspection (PSI). If there is an issue with SMDJ12A, 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 SMDJ12A part is unused and in its original packaging.
Return procedure for SMDJ12A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMDJ12A Tags
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