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Vishay General Semiconductor - Diodes Division SMAJ12A-E3/5A
- Part No.:
- SMAJ12A-E3/5A
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ12A-E3/5A.pdf
- Description:
- TVS DIODE 12VWM 19.9VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:6,425
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Product details
Overview
SMAJ12A-E3/5A 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, clamps transients to ≤19.9 V at 20.1 A peak pulse current (10/1000 μs), and delivers 400 W peak pulse power - used in automotive body control modules to protect CAN transceiver inputs against load dump and ISO 7637-2 pulses.
For engineers reviewing the SMAJ12A-E3/5A datasheet, SMAJ12A-E3/5A pinout, SMAJ12A-E3/5A application, or SMAJ12A-E3/5A equivalent, key selection criteria include unidirectional polarity, SMA (DO-214AC) package compatibility with automated SMT placement, AEC-Q101 qualification status, thermal resistance (RθJA = 120 °C/W), and clamping performance under repetitive surge conditions.
Technical Context
This TVS diode operates as a voltage-clamped crowbar device: when reverse voltage exceeds VBR, it avalanches into low-impedance conduction, diverting surge current away from protected ICs. Its glass-passivated junction ensures stable breakdown characteristics and long-term reliability under repeated transient stress.
The SMAJ12A-E3/5A is rated for -55 °C to +150 °C operating junction temperature, supports 40 A non-repetitive forward surge (8.3 ms half-sine), and exhibits 0.083 %/°C temperature coefficient of VBR - enabling predictable clamping behavior across automotive thermal environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 12 V - maximum continuous reverse operating voltage before leakage exceeds 1 μA; defines safe DC rail margin for 12 V systems. |
| VBR @ IT=1 mA | 13.3–14.7 V - guaranteed avalanche initiation range; ensures consistent turn-on across production lots and temperature. |
| VC @ IPPM=20.1 A | ≤19.9 V - clamped voltage during 10/1000 μs surge; determines maximum stress on downstream MOSFET gate or MCU I/O. |
| PPPM | 400 W - peak pulse power handling (10/1000 μs); sufficient for ISO 16750-2 Pulse 5a (load dump) suppression in 12 V vehicle networks. |
| RθJA | 120 °C/W - junction-to-ambient thermal resistance on standard 0.2" × 0.2" copper pads; informs derating above 25 °C ambient. |
| IFSM | 40 A - single half-sine surge rating (8.3 ms); validates robustness against motor commutation spikes in BLDC drivers. |
| Junction Temp | -55 to +150 °C - qualified operating range; meets automotive under-hood and industrial control cabinet requirements. |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, molded plastic case with matte tin-plated leads; meets UL 94 V-0, MSL Level 1 (260 °C reflow peak), and JESD201 Class 2 whisker resistance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (banded end) | Surge current sink node | Connected to protected line (e.g., CAN_H); conducts avalanche current to ground during overvoltage events. |
| Anode | Reference / return path | Typically tied to system ground or low-impedance return plane; completes surge current path during clamping. |
Key Features
| Feature | Design Value |
|---|---|
| 400 W peak pulse power (10/1000 μs) | Enables single-device protection against ISO 7637-2 Test 4 (alternator load dump) without parallel staging. |
| Low incremental surge resistance | Minimizes VC overshoot during fast-rising transients (<1 ns rise time), improving protection margin for high-speed interfaces. |
| Glass passivated junction | Ensures stable VBR and low leakage (<1 μA at VWM) over 15+ year automotive service life and thermal cycling. |
| AEC-Q101 qualified (HE3/HM3 variants) | Validates reliability for automotive electronics; SMAJ12A-E3/5A is RoHS-compliant commercial grade - upgrade path to HE3 available. |
| MSL Level 1 moisture sensitivity | Allows unlimited floor life and standard reflow profiles (peak 260 °C), eliminating bake requirements in high-volume SMT lines. |
Applications
| Automotive Body Control Module (BCM) | Industrial PLC Digital Input Protection |
|---|---|
|
Use Scenario: Protects 12 V supply input of BCM microcontroller from alternator load dump and relay coil flyback. IC Role / Device Role / Timing Role: Primary clamping device placed directly at connector entry point, upstream of LDO and MCU. Use Value: Limits transient voltage to ≤19.9 V at 20.1 A, preventing latch-up or gate oxide damage in 3.3 V/5 V logic supplies. |
Use Scenario: Shields 24 V digital input channel of PLC I/O module from field-wiring induced surges and ESD. IC Role / Device Role / Timing Role: First-line transient suppressor on terminal block side, before optocoupler or Schmitt trigger input stage. Use Value: Clamps 1 kV/50 Ω surge (IEC 61000-4-5) within 1 ns, maintaining <1 μA leakage at 24 V nominal to avoid false triggering. |
| Automotive Infotainment Power Rail | Consumer Appliance Motor Driver Stage |
|
Use Scenario: Safeguards USB-C PD controller and display interface power rails in head unit against battery reverse connection and jump-start transients. IC Role / Device Role / Timing Role: Unidirectional TVS on +12 V main rail, coordinated with upstream fuse and downstream ceramic filtering. Use Value: Withstands 40 A 8.3 ms forward surge (IFSM), surviving accidental 24 V jump-start events without degradation. |
Use Scenario: Suppresses inductive kickback from brushed DC motor commutation in smart home vacuum or power tool controllers. IC Role / Device Role / Timing Role: Parallel-mounted across H-bridge low-side MOSFET drain-source, clamping flyback energy. Use Value: Delivers 400 W pulse power at 12 V bus, reducing snubber capacitor size and PCB area versus RC solutions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ12A-M3/5A | Halogen-free, RoHS-compliant variant with identical electrical specs and SMA package. | No functional difference; selected where halogen-free BOM compliance is mandated (e.g., EU medical devices). | Direct material substitution if halogen-free certification is required; same footprint, thermal, and electrical behavior. |
| SMAJ12CA-E3/5A | Bidirectional version: symmetric VBR (13.3–14.7 V) in both polarities; no cathode marking. | Required for AC-coupled or differential signal lines (e.g., RS-485, CAN FD) where polarity reversal may occur. | Use only when bidirectional clamping is needed; not interchangeable in unidirectional DC rail protection due to lack of polarity reference. |
Compared with SMAJ12A-E3/5A, the M3/5A offers identical protection performance with halogen-free construction, while the SMAJ12CA-E3/5A enables symmetrical clamping but sacrifices cathode-defined polarity - making it unsuitable for DC rail applications requiring directional surge diversion.
Availability
SMAJ12A-E3/5A is available at Aetrix Electronics and suitable for automotive electronics, industrial PLCs, and consumer appliance designs requiring stable component supply, full traceability, and long-term lifecycle support.
Supply support for SMAJ12A-E3/5A 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, TVS devices, and optoelectronics with emphasis on reliability, precision, and automotive-grade qualification.
The SMAJ series was developed specifically for robust, surface-mount transient suppression in harsh environments - targeting automotive, industrial, and telecom infrastructure where failure modes must be mitigated without adding complexity.
FAQ
What is the maximum clamping voltage of the SMAJ12A-E3/5A under a 10/1000 μs surge?
The SMAJ12A-E3/5A clamps to a maximum of 19.9 V when subjected to its rated peak pulse current of 20.1 A (10/1000 μs waveform). This value is measured per IEC 61000-4-5 test conditions and defines the upper voltage limit imposed on protected circuitry during transient events - critical for ensuring compatibility with 3.3 V or 5 V logic interfaces downstream of the device.
Is the SMAJ12A-E3/5A suitable for automotive applications requiring AEC-Q101 qualification?
The SMAJ12A-E3/5A itself is RoHS-compliant commercial-grade; however, Vishay offers the functionally identical SMAJ12A-HE3_X variant (e.g., SMAJ12AHE3_A) that is fully AEC-Q101 qualified. For production automotive use, specify the HE3 suffix to ensure qualification - the SMAJ12A-E3/5A serves as a drop-in compatible evaluation or non-automotive alternative.
How does the SMAJ12A-E3/5A differ from the SMAJ12CA-E3/5A?
The SMAJ12A-E3/5A is unidirectional with a marked cathode band and clamps only in reverse bias, whereas the SMAJ12CA-E3/5A is bidirectional - offering symmetric clamping in both polarities with no polarity marking. This makes the CA version appropriate for AC signals or differential buses like RS-485, but unsuitable for DC rail protection where directional surge current routing is required.
What is the thermal resistance and how does it affect layout design for the SMAJ12A-E3/5A?
The SMAJ12A-E3/5A has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W when mounted on 0.2" × 0.2" copper pads per terminal. To maintain safe operation at elevated ambient temperatures, PCB layout must provide adequate copper area and minimize thermal isolation - especially important in high-duty-cycle surge environments such as motor drive feedback paths.
Can the SMAJ12A-E3/5A be used to protect a 12 V CAN bus line?
Yes - the SMAJ12A-E3/5A is commonly deployed to protect CAN_H and CAN_L lines in 12 V automotive networks. Its 12 V standoff voltage aligns with nominal bus levels, and its ≤19.9 V clamping ensures transceivers (e.g., TJA1042, SN65HVD230) remain within absolute maximum ratings during ISO 7637-2 pulses. For bidirectional protection, SMAJ12CA-E3/5A is preferred; for unidirectional rail protection, SMAJ12A-E3/5A is optimal.
SMAJ12A-E3/5A 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-E3/5A FAQ
1.How can I place an order for SMAJ12A-E3/5A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ12A-E3/5A 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-E3/5A reliable?
The price and inventory of SMAJ12A-E3/5A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ12A-E3/5A is usually 5 days.
3.What payment methods are accepted for SMAJ12A-E3/5A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ12A-E3/5A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ12A-E3/5A?
SMAJ12A-E3/5A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ12A-E3/5A 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-E3/5A?
For technical support, including SMAJ12A-E3/5A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ12A-E3/5A requirements.
6.How does Aetrix verify that SMAJ12A-E3/5A is sourced from the original manufacturer or authorized distributors?
All SMAJ12A-E3/5A 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-E3/5A meets industry standards.
7.What is the process for return or replacement of SMAJ12A-E3/5A?
All SMAJ12A-E3/5A units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ12A-E3/5A, 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-E3/5A part is unused and in its original packaging.
Return procedure for SMAJ12A-E3/5A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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