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Vishay General Semiconductor - Diodes Division SMAJ12CAHM3_A/I
- Part No.:
- SMAJ12CAHM3_A/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ12CAHM3_A/I.pdf
- Description:
- TVS DIODE 12VWM 19.9VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:5,745
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Product details
Overview
SMAJ12CAHM3_A/I from Vishay General Semiconductor is a bidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMA (DO-214AC) package, designed for clamping voltage transients on signal or power lines. It features a 12 V stand-off voltage (VWM), 13.3–14.7 V breakdown voltage (VBR) at 1 mA, 19.9 V maximum clamping voltage (VC) at 20.1 A peak pulse current (IPPM), and 400 W peak pulse power rating with 10/1000 μs waveform - used to protect MOSFETs, ICs, and sensor signal lines in automotive and industrial control systems.
For engineers reviewing the SMAJ12CAHM3_A/I datasheet, SMAJ12CAHM3_A/I pinout, SMAJ12CAHM3_A/I application, or SMAJ12CAHM3_A/I equivalent, key selection criteria include bidirectional clamping capability, AEC-Q101 qualification, low clamping ratio (VC/VBR ≈ 1.45), MSL Level 1 moisture sensitivity, and halogen-free RoHS compliance per HM3 suffix.
Technical Context
This device operates as a voltage-clamping protector with symmetrical avalanche breakdown in both directions, enabling transient suppression without polarity constraints on AC-coupled or differential signal paths. Its glass-passivated junction ensures stable leakage (<1 μA at VWM) and fast response time (<1 ns), critical for protecting sensitive analog front-ends and high-speed digital interfaces.
The SMAJ12CAHM3_A/I delivers 400 W peak pulse power up to 78 V and derates to 300 W above that threshold, with thermal resistance RθJA = 120 °C/W and RθJL = 30 °C/W - confirming suitability for PCB-mounted operation on 5.0 mm × 5.0 mm copper pads without forced cooling in ambient temperatures up to +125 °C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 12 V - maximum continuous reverse operating voltage before clamping initiates; defines safe DC/AC signal swing margin. |
| VBR min/max | 13.3 V / 14.7 V at IT = 1 mA - guaranteed avalanche onset range; ensures predictable turn-on across temperature and unit variation. |
| VC @ IPPM | 19.9 V at 20.1 A - clamped voltage during 10/1000 μs surge; limits downstream stress to <20 V under worst-case 400 W transient. |
| PPPM | 400 W - peak pulse power handling with 10/1000 μs waveform; supports IEC 61000-4-5 Level 4 surge immunity testing. |
| ID @ VWM | <1 μA - ultra-low reverse leakage at rated stand-off; preserves signal integrity in high-impedance sensor or reference circuits. |
| TJ max. | +150 °C - maximum junction temperature; enables use in under-hood automotive environments and sealed industrial enclosures. |
| MSL Level | Level 1 (J-STD-020) - no floor life limitation; supports standard SMT reflow without dry-pack or baking requirements. |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, molded plastic case with matte tin-plated leads; dimensions 4.50 mm × 2.79 mm × 2.29 mm (L × W × H); meets UL 94 V-0 flammability rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Transient current entry (bidirectional) | Acts as cathode during positive half-cycle and anode during negative half-cycle; no polarity marking on device body. |
| Cathode | Transient current exit (bidirectional) | Functions symmetrically with Anode; bidirectional conduction eliminates need for orientation-aware layout. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables single-device protection of AC signals, differential buses (e.g., RS-485), or ungrounded power rails without polarity concerns. |
| AEC-Q101 qualified | Validated for automotive applications including engine control units, ADAS sensors, and infotainment power supplies per stress test requirements. |
| Halogen-free & RoHS-compliant (HM3) | Meets EU RoHS Directive 2011/65/EU and JEDEC J-STD-20E; supports green manufacturing and end-of-life recycling compliance. |
| 400 W peak pulse power | Withstands 10/1000 μs surges up to 20.1 A - sufficient for ISO 7637-2 Pulse 1/2a/5a and IEC 61000-4-5 Combination Wave (1.2/50 μs + 8/20 μs). |
| Low clamping ratio (VC/VBR ≈ 1.45) | Minimizes overvoltage exposure to protected ICs - critical for 3.3 V or 5 V logic interfaces where clamp overshoot must stay below absolute maximum ratings. |
Applications
| Automotive Sensor Protection | Industrial PLC I/O Protection |
|---|---|
|
Use Scenario: Protecting CAN bus transceivers and analog sensor inputs (e.g., pressure, temperature) from load dump and ESD events in vehicle ECUs. IC Role / Device Role / Timing Role: Bidirectional voltage clamp placed directly at connector interface to shunt transients before reaching PHY layer. Use Value: Maintains signal fidelity under ISO 16750-2 load dump (up to 120 V/1 s) while limiting clamped voltage to ≤19.9 V - within 3.3 V transceiver absolute max rating. |
Use Scenario: Safeguarding 24 V digital input modules in programmable logic controllers against field-wiring induced surges and relay coil flyback. IC Role / Device Role / Timing Role: Parallel-connected TVS on each channel's input line to clamp transients before optocoupler or Schmitt trigger input stage. Use Value: Withstands repetitive 400 W pulses at 0.01% duty cycle - enables reliable operation in factory automation environments with frequent inductive switching. |
| Consumer USB Port Protection | Telecom Line Interface Protection |
|
Use Scenario: Shielding USB 2.0 D+/D− lines in portable devices from human-body-model (HBM) ESD and cable discharge events. IC Role / Device Role / Timing Role: Low-capacitance bidirectional TVS placed adjacent to USB connector to divert >8 kV contact ESD per IEC 61000-4-2. Use Value: Sub-1 μA leakage at 12 V VWM prevents signal attenuation; fast <1 ns response ensures ESD energy is clamped before reaching USB PHY. |
Use Scenario: Protecting Ethernet PHY or xDSL line drivers from lightning-induced surges entering via RJ-45 or modular telephone jacks. IC Role / Device Role / Timing Role: Primary-level TVS on tip/ring pairs upstream of isolation transformers and common-mode chokes. Use Value: 400 W rating supports IEC 61000-4-5 Level 3 (2 kV line-earth) surge immunity; bidirectional symmetry matches balanced telecom signaling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ12CAHE3_A/I | Same electrical specs, but RoHS-compliant commercial grade (E3) without halogen-free certification; not AEC-Q101 qualified. | Limited to non-automotive industrial or consumer use where halogen-free and automotive qualification are not required. | Select when cost sensitivity outweighs halogen-free or automotive qualification needs; identical footprint and soldering profile. |
| SMBJ12CAHM3_A/I | Same VWM/VBR/VC specs but in larger SMB (DO-214AA) package; 600 W peak pulse power (vs. 400 W); higher thermal mass. | Better suited for higher-energy surge environments (e.g., outdoor telecom cabinets) where PCB space allows larger footprint. | Choose when system-level surge testing exceeds IEC 61000-4-5 Level 4 or when thermal derating margin is critical under sustained ambient >105 °C. |
Compared with SMAJ12CAHE3_A/I, the SMAJ12CAHM3_A/I adds halogen-free construction and AEC-Q101 qualification for automotive use; compared with SMBJ12CAHM3_A/I, it trades 200 W pulse power headroom for 30% smaller board area and lower parasitic inductance - optimizing for space-constrained, high-reliability embedded nodes.
Availability
SMAJ12CAHM3_A/I is available at Aetrix Electronics and suitable for automotive sensor modules, industrial PLC I/O cards, and telecom line interface designs requiring stable component supply, long-term lifecycle support, and traceable halogen-free sourcing.
Supply support for SMAJ12CAHM3_A/I 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, precision, and application-specific optimization.
The SMAJ series is engineered for robust transient suppression in harsh environments - targeting automotive, industrial, and telecom applications where failure due to voltage surges must be eliminated through proven clamping performance and qualification rigor.
FAQ
What is the clamping voltage of SMAJ12CAHM3_A/I at its rated peak pulse current?
The SMAJ12CAHM3_A/I has a maximum clamping voltage (VC) of 19.9 V at 20.1 A peak pulse current (IPPM) with a 10/1000 μs waveform. This value is measured per ANSI/IEEE C62.35 and guarantees that downstream circuitry sees no more than 19.9 V during a standardized surge event - a critical parameter for ensuring compatibility with 3.3 V or 5 V logic interfaces in the protected system.
Is SMAJ12CAHM3_A/I suitable for automotive applications?
Yes, SMAJ12CAHM3_A/I is AEC-Q101 qualified, as confirmed by Vishay's ordering code suffix "HM3_X" (where "X" denotes revision A). It undergoes stress testing for temperature cycling, humidity bias, mechanical shock, and high-temperature operating life - making it suitable for under-hood and cabin ECU applications including ADAS sensors, body control modules, and infotainment power rails.
How does the HM3 suffix differ from E3 or HE3 in the SMAJ12CA family?
The HM3 suffix on SMAJ12CAHM3_A/I indicates halogen-free, RoHS-compliant, and AEC-Q101 qualified construction. In contrast, E3 is RoHS-compliant commercial grade only, and HE3 adds AEC-Q101 qualification but lacks halogen-free certification. All three share identical electrical specs and SMA package, but HM3 satisfies strict automotive material compliance (e.g., JESD201 Class 2 whisker resistance) and green manufacturing mandates.
What is the maximum reverse leakage current for SMAJ12CAHM3_A/I at its stand-off voltage?
The SMAJ12CAHM3_A/I exhibits a maximum reverse leakage current (ID) of 1.0 μA at its 12 V stand-off voltage (VWM), tested at TA = 25 °C. This ultra-low leakage preserves signal integrity in high-impedance circuits such as sensor bias networks or precision reference dividers - a key advantage over higher-leakage alternatives in battery-powered or low-power IoT endpoints.
Does SMAJ12CAHM3_A/I require special PCB layout considerations?
Yes - for optimal surge performance, Vishay specifies mounting SMAJ12CAHM3_A/I on minimum 5.0 mm × 5.0 mm copper pads per terminal to achieve rated 400 W pulse power. Short, wide traces to ground/power planes minimize inductance; avoid vias in series with TVS terminals. The device's bidirectional symmetry eliminates orientation constraints, simplifying automated placement on dense PCBs.
SMAJ12CAHM3_A/I 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:
- -
- Bidirectional Channels:
- 1
- 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:
- Telecom
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ12CAHM3_A/I FAQ
1.How can I place an order for SMAJ12CAHM3_A/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ12CAHM3_A/I 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 SMAJ12CAHM3_A/I reliable?
The price and inventory of SMAJ12CAHM3_A/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ12CAHM3_A/I is usually 5 days.
3.What payment methods are accepted for SMAJ12CAHM3_A/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ12CAHM3_A/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ12CAHM3_A/I?
SMAJ12CAHM3_A/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ12CAHM3_A/I 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 SMAJ12CAHM3_A/I?
For technical support, including SMAJ12CAHM3_A/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ12CAHM3_A/I requirements.
6.How does Aetrix verify that SMAJ12CAHM3_A/I is sourced from the original manufacturer or authorized distributors?
All SMAJ12CAHM3_A/I 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 SMAJ12CAHM3_A/I meets industry standards.
7.What is the process for return or replacement of SMAJ12CAHM3_A/I?
All SMAJ12CAHM3_A/I units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ12CAHM3_A/I, 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 SMAJ12CAHM3_A/I part is unused and in its original packaging.
Return procedure for SMAJ12CAHM3_A/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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