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Vishay General Semiconductor - Diodes Division SMAJ12A-M3/5A
- Part No.:
- SMAJ12A-M3/5A
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ12A-M3/5A.pdf
- Description:
- TVS DIODE 12VWM 19.9VC DO214AC
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
SMAJ12A-M3/5A from Vishay General Semiconductor is a unidirectional surface-mount Transient Voltage Suppressor (TVS) diode designed for primary overvoltage protection of DC power rails and signal lines. It features a 12 V standoff voltage (VWM), 13.3–14.7 V breakdown range at 1 mA, 19.9 V clamping voltage at 20.1 A peak pulse current, and 400 W peak pulse power rating with 10/1000 μs waveform - deployed in automotive infotainment power inputs, industrial sensor I/O protection, and USB VBUS line surge suppression.
For engineers reviewing the SMAJ12A-M3/5A datasheet, SMAJ12A-M3/5A pinout, SMAJ12A-M3/5A application, or SMAJ12A-M3/5A equivalent, key selection criteria include clamping voltage margin vs. protected IC's absolute maximum rating, thermal resistance (RθJA = 120 °C/W), unidirectional polarity marking, and halogen-free RoHS compliance per M3 suffix.
Technical Context
This TVS operates as a voltage-clamped shunt device: under normal conditions it presents high impedance (<1 μA leakage at 12 V), then avalanches rapidly (<1 ps response) when transient voltage exceeds VBR, diverting surge current to ground while limiting downstream voltage to ≤19.9 V. Its glass-passivated junction ensures stable breakdown and low incremental surge resistance.
Designed for PCB-level protection, SMAJ12A-M3/5A mounts on 0.2" × 0.2" copper pads, supports automated placement in SMA (DO-214AC) package, and meets MSL Level 1 (260 °C reflow peak). It is rated for -55 °C to +150 °C operation and qualified to AEC-Q101 when ordered with HE3/HM3 suffixes - though SMAJ12A-M3/5A itself is commercial-grade.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 12 V - Maximum continuous reverse operating voltage before leakage exceeds 1 μA; sets upper limit for protected circuit's nominal rail. |
| VBR @ IT=1 mA | 13.3–14.7 V - Verified breakdown threshold defining turn-on onset; ensures reliable conduction before downstream IC damage. |
| VC @ IPPM=20.1 A | 19.9 V - Clamped voltage during 10/1000 μs surge; must stay below protected device's absolute max rating (e.g., 20 V). |
| PPPM | 400 W - Peak pulse power handling capability; defines maximum transient energy absorption without failure. |
| RθJA | 120 °C/W - Junction-to-ambient thermal resistance; determines temperature rise under sustained power dissipation (e.g., 3.3 W derated above 25 °C). |
| IFSM | 40 A - Non-repetitive forward surge current rating (8.3 ms half-sine); validates robustness against inrush or fault currents. |
| Package | SMA (DO-214AC) - Surface-mount outline with 2.54 mm lead pitch; compatible with standard SMT pick-and-place and reflow profiles. |
Pinout & Package
Package: SMA (DO-214AC), molded plastic case with matte tin-plated leads, UL 94 V-0 rated compound, cathode indicated by band on one end.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry point in forward bias; connected to protected line (e.g., VBUS or signal) | When used in unidirectional configuration, anode connects to lower-potential node (e.g., GND side of series resistor or directly to GND for clamp-to-rail). |
| Cathode | Current exit point in forward bias; marked with band | Connected to higher-potential node (e.g., VBUS or signal line); avalanche conduction occurs from cathode to anode during overvoltage events. |
Key Features
| Feature | Design Value |
|---|---|
| 400 W peak pulse power (10/1000 μs) | Enables protection against IEC 61000-4-5 Level 3 surges (1 kV/2 Ω) on 12 V systems without derating. |
| Low clamping ratio (VC/VBR ≈ 1.42) | Minimizes overvoltage stress on downstream components - critical for 13.3 V-rated microcontrollers or transceivers. |
| Halogen-free, RoHS-compliant (M3 suffix) | Meets environmental compliance requirements for automotive and industrial OEMs without compromising electrical performance. |
| MSL Level 1 moisture sensitivity | Allows unlimited floor life and standard reflow processing at 260 °C peak - eliminates baking requirements pre-assembly. |
| 150 °C maximum junction temperature | Supports operation in under-hood automotive environments and thermally constrained industrial enclosures. |
Applications
| Automotive Infotainment Power Input | Industrial Sensor Signal Line Protection |
|---|---|
Use Scenario: 12 V supply rail feeding head unit MCU and display driver ICs exposed to load dump transients up to 35 V. IC Role / Device Role / Timing Role: Unidirectional shunt TVS placed between VBAT and GND, upstream of DC-DC converter input. Use Value: Clamps transients to ≤19.9 V within nanoseconds, preventing latch-up or gate oxide damage in 20 V max-rated buck controllers. |
Use Scenario: 4–20 mA analog current loop interface in PLC I/O module subjected to ESD and inductive switching noise. IC Role / Device Role / Timing Role: TVS mounted across signal and return lines, referenced to local ground plane. Use Value: Limits induced voltage spikes to <20 V, preserving accuracy of 24-bit ADCs and preventing false triggering of current-sense comparators. |
| USB Type-A VBUS Line Protection | Telecom DSL Line Interface |
Use Scenario: VBUS line in host-side USB port experiencing hot-plug surges and contact bounce during cable insertion. IC Role / Device Role / Timing Role: Unidirectional TVS from VBUS to GND, placed immediately after USB connector. Use Value: Absorbs 30 A transient peaks without degradation, maintaining VBUS regulation within ±5% tolerance during 100 ns events. |
Use Scenario: Primary protection stage for ADSL/VDSL line interface ICs receiving lightning-induced surges on twisted-pair telecom lines. IC Role / Device Role / Timing Role: First-stage TVS across tip/ring differential pair, before gas discharge tube and secondary filtering. Use Value: Provides sub-20 ns response to fast-rising surges, reducing let-through energy to <10 mJ before secondary protectors activate. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ12A-E3/5A | Same electrical specs; RoHS-compliant but contains brominated flame retardants (non-halogen-free) | Acceptable for commercial-grade designs where halogen-free requirement is not mandated | Select when cost sensitivity outweighs halogen-free compliance; identical footprint and assembly process. |
| SMAJ12CA-M3/5A | Bidirectional variant; symmetric breakdown (13.3–14.7 V) in both polarities; no polarity marking | Required for AC-coupled or floating signal lines (e.g., RS-485, CAN bus) where reverse polarity transients occur | Choose only if bidirectional protection is needed; not a drop-in replacement due to polarity and layout implications. |
Compared with SMAJ12A-E3/5A, SMAJ12A-M3/5A adds halogen-free compliance without sacrificing surge rating or thermal performance; versus SMAJ12CA-M3/5A, it provides optimized unidirectional clamping for DC rails but requires correct polarity orientation during placement.
Availability
SMAJ12A-M3/5A is available at Aetrix Electronics and suitable for automotive infotainment power inputs, industrial sensor signal line protection, and USB VBUS line surge suppression requiring stable component supply, full traceability, and long-term lifecycle support.
Supply support for SMAJ12A-M3/5A 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
Vishay General Semiconductor is a global leader in discrete semiconductors, specializing in diodes, rectifiers, MOSFETs, and protection devices with emphasis on reliability, power efficiency, and automotive qualification.
The SMAJ series delivers standardized, high-power TVS diodes for board-level transient suppression across consumer, industrial, and automotive applications - engineered for consistent clamping, low leakage, and robust surge endurance in compact surface-mount packages.
FAQ
What is the maximum clamping voltage of SMAJ12A-M3/5A at its rated peak pulse current?
The SMAJ12A-M3/5A exhibits a maximum clamping voltage (VC) of 19.9 V when subjected to its rated peak pulse current (IPPM) of 20.1 A using the standard 10/1000 μs waveform. This value is measured per JEDEC test conditions and guarantees that downstream circuitry sees no more than 19.9 V during such transient events - a critical parameter for ensuring compatibility with 20 V absolute maximum-rated ICs. The SMAJ12A-M3/5A maintains this clamping performance across its specified operating temperature range.
Does SMAJ12A-M3/5A meet AEC-Q101 qualification for automotive use?
No, SMAJ12A-M3/5A is a commercial-grade part with halogen-free RoHS compliance (M3 suffix) but is not AEC-Q101 qualified. Vishay offers AEC-Q101 variants under ordering codes SMAJ12AHE3_X or SMAJ12AHM3_X (where "_X" denotes revision letter). These qualified versions undergo additional stress testing including temperature cycling, humidity bias, and accelerated life testing - required for under-hood or safety-critical automotive modules. The SMAJ12A-M3/5A remains suitable for non-safety automotive applications like infotainment power rails where qualification is not mandated.
How does the M3 suffix differ from E3 in SMAJ12A-M3/5A versus SMAJ12A-E3/5A?
The M3 suffix in SMAJ12A-M3/5A indicates halogen-free, RoHS-compliant construction using bromine- and chlorine-free flame retardants in the epoxy molding compound, whereas E3 denotes RoHS compliance without halogen-free assurance. Both share identical electrical characteristics, thermal ratings, and mechanical dimensions. The SMAJ12A-M3/5A satisfies stricter environmental mandates (e.g., JPCA-001, IEC 61249-2-21) for green electronics manufacturing, especially in EU and Japanese markets. Designers selecting SMAJ12A-M3/5A retain full drop-in compatibility with E3 variants in layout and assembly.
What is the recommended PCB pad layout for optimal thermal performance of SMAJ12A-M3/5A?
Vishay specifies a minimum 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pad area per terminal for SMAJ12A-M3/5A to achieve its rated 400 W peak pulse power and 3.3 W steady-state power dissipation. These pads must be connected to internal ground/power planes via multiple thermal vias (≥4 per pad, 0.3 mm diameter) to minimize RθJA and prevent localized overheating during repetitive surges. Deviating from this layout increases junction temperature - e.g., using 1.0 mm² pads may raise RθJA beyond 120 °C/W, derating power capability by >30%. The SMAJ12A-M3/5A datasheet provides exact dimensional drawings for DO-214AC mounting.
Can SMAJ12A-M3/5A be used in bidirectional signal protection applications?
No - SMAJ12A-M3/5A is strictly unidirectional and features a cathode band marking; applying reverse voltage beyond its 12 V standoff rating causes high leakage and potential failure. For bidirectional protection (e.g., RS-485, CAN, or AC-coupled audio), the SMAJ12CA-M3/5A variant must be used instead. That part has symmetric breakdown in both directions and no polarity marking. Substituting SMAJ12A-M3/5A in a bidirectional role risks catastrophic short-circuit during negative transients, invalidating system-level EMC and safety certifications. Always verify polarity alignment before placing SMAJ12A-M3/5A in circuit.
SMAJ12A-M3/5A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AC, SMA
- Series:
- TransZorb®
- 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):
- 20.1A
- 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)
SMAJ12A-M3/5A FAQ
1.How can I place an order for SMAJ12A-M3/5A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ12A-M3/5A 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 SMAJ12A-M3/5A reliable?
The price and inventory of SMAJ12A-M3/5A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ12A-M3/5A is usually 5 days.
3.What payment methods are accepted for SMAJ12A-M3/5A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ12A-M3/5A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ12A-M3/5A?
SMAJ12A-M3/5A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ12A-M3/5A 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 SMAJ12A-M3/5A?
For technical support, including SMAJ12A-M3/5A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ12A-M3/5A requirements.
6.How does Aetrix verify that SMAJ12A-M3/5A is sourced from the original manufacturer or authorized distributors?
All SMAJ12A-M3/5A 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 SMAJ12A-M3/5A meets industry standards.
7.What is the process for return or replacement of SMAJ12A-M3/5A?
All SMAJ12A-M3/5A units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ12A-M3/5A, 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 SMAJ12A-M3/5A part is unused and in its original packaging.
Return procedure for SMAJ12A-M3/5A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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