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Vishay General Semiconductor - Diodes Division SMAJ12AHM3/I
- Part No.:
- SMAJ12AHM3/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ12AHM3/I.pdf
- Description:
- TVS DIODE 12VWM 19.9VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:5,840
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Product details
Overview
SMAJ12AHM3/I from Vishay General Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, designed to protect sensitive electronics against voltage transients induced by inductive load switching and lightning surges. 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 (10/1000 μs waveform).
For engineers reviewing the SMAJ12AHM3/I datasheet, SMAJ12AHM3/I pinout, SMAJ12AHM3/I application, or SMAJ12AHM3/I equivalent, key selection criteria include clamping performance under 20.1 A surge, thermal resistance (RθJA = 120 °C/W), AEC-Q101 qualification status, halogen-free RoHS compliance (HM3 suffix), and compatibility with automated SMT placement on 5.0 mm × 5.0 mm copper pads.
Technical Context
The SMAJ12AHM3/I operates as a unidirectional avalanche diode, conducting only when reverse voltage exceeds its breakdown threshold (VBR), thereby shunting transient energy to ground. Its glass-passivated junction ensures stable leakage (<1.0 μA at VWM) and fast response time (<1.0 ps), critical for protecting MOSFET gates and IC signal lines.
Designed for surface-mount use on PCBs with minimum recommended pad layout, it delivers 400 W peak pulse power up to 78 V and derates to 300 W above that level. The device meets MSL Level 1 per J-STD-020 and supports peak reflow temperatures up to 260 °C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 12 V - Maximum continuous reverse operating voltage before clamping begins; defines safe signal line operating margin. |
| VBR min/max | 13.3 V / 14.7 V at 1 mA - Confirmed avalanche onset range; ensures predictable turn-on during transients. |
| VC @ IPPM | 19.9 V at 20.1 A - Clamped voltage during 10/1000 μs surge; determines maximum stress on protected downstream circuitry. |
| PPPM | 400 W (≤78 V), 300 W (>78 V) - Peak transient energy absorption capability; defines protection robustness for automotive/industrial environments. |
| RθJA | 120 °C/W - Junction-to-ambient thermal resistance; requires ≥5.0 mm × 5.0 mm copper pads for rated power dissipation. |
| IFSM | 40 A - Non-repetitive forward surge rating (8.3 ms half-sine); supports inrush tolerance in power rail applications. |
| TJ max | +150 °C - Maximum junction temperature; enables operation in under-hood automotive or industrial enclosures. |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, low-profile case with matte tin-plated leads solderable per J-STD-002. Cathode indicated by band marking on unidirectional variant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to system ground or lower-potential node; completes current path during transient clamping. |
| Cathode | Reverse-biased clamping terminal | Connected to protected line (e.g., 12 V rail or signal trace); initiates avalanche conduction when VAK > VBR. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD testing per JEDEC standards. |
| Halogen-free & RoHS-compliant (HM3) | Meets environmental compliance requirements for Tier-1 automotive and industrial OEM supply chains. |
| 400 W peak pulse power (10/1000 μs) | Provides robust protection against ISO 7637-2 Pulse 1/2a/5a and IEC 61000-4-5 surge events. |
| Low incremental surge resistance | Minimizes voltage overshoot during fast-rising transients (e.g., relay coil flyback), enhancing protection fidelity. |
| MSL Level 1, 260 °C peak reflow | Enables single-pass lead-free reflow assembly without moisture-related popcorn failure risk. |
Applications
| Automotive Power Rail Protection | Industrial Sensor Signal Line Protection |
|---|---|
Use Scenario: Protecting 12 V battery-fed ECUs from load dump and alternator ripple transients. IC Role / Device Role / Timing Role: Unidirectional TVS placed between power rail and chassis ground to clamp surges exceeding 12 V. Use Value: Limits clamped voltage to ≤19.9 V at 20.1 A, preventing damage to downstream regulators and microcontrollers. | Use Scenario: Shielding analog sensor outputs (e.g., pressure, temperature) from ESD and cable discharge events. IC Role / Device Role / Timing Role: TVS connected between signal line and ground, leveraging sub-nanosecond response to suppress <15 kV HBM ESD. Use Value: Maintains signal integrity with <1.0 μA leakage at 12 V, avoiding DC offset errors in precision measurement circuits. |
| Consumer Power Adapter Input Stage | MOSFET Gate Driver Protection |
Use Scenario: Safeguarding AC-DC adapter primary-side controllers from surge coupling via mains input. IC Role / Device Role / Timing Role: Unidirectional TVS across bulk capacitor terminals to absorb line-to-ground transients. Use Value: Withstands 400 W pulses without degradation, supporting UL 497B recognition for surge protector classification. | Use Scenario: Preventing gate oxide rupture in high-side N-channel MOSFETs due to Miller-induced voltage spikes. IC Role / Device Role / Timing Role: TVS placed between gate and source to clamp dv/dt-induced overvoltage during switching transitions. Use Value: Fast avalanche response (<1 ns) limits gate-source voltage to ≤19.9 V, ensuring reliable FET operation under hard-switching conditions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ12AHE3/I | RoHS-compliant but not halogen-free; lacks AEC-Q101 qualification. | Suitable for commercial-grade consumer or industrial equipment where automotive qualification is unnecessary. | Select when halogen-free content and automotive reliability are not required; lower cost alternative. |
| SMAJ12A-M3/5A | Same electrical specs and halogen-free construction, but supplied in 13" tape-and-reel (7500 pcs) vs. SMAJ12AHM3/I's 13" reel with I-packaging code. | Identical performance; differs only in packaging logistics and traceability coding. | Choose based on procurement volume and factory line feed requirements-not functional differentiation. |
Compared with SMAJ12AHM3/I, SMAJ12AHE3/I trades AEC-Q101 and halogen-free compliance for cost efficiency in non-automotive designs, while SMAJ12A-M3/5A offers identical specifications with alternate reel packaging-neither is pin-compatible in the sense of drop-in replacement across all qualification tiers, but both serve overlapping protection functions in appropriate contexts.
Availability
SMAJ12AHM3/I is available at Aetrix Electronics and suitable for automotive ECU power rail protection, industrial sensor interface hardening, and consumer power adapter surge suppression requiring stable component supply, full traceability, and long-term lifecycle support.
Supply support for SMAJ12AHM3/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, power efficiency, and automotive-grade qualification.
The SMAJ series is part of Vishay's TRANSZORB® TVS platform, engineered specifically for high-energy transient suppression in harsh environments-including under-hood automotive, industrial motor drives, and telecom infrastructure-where consistent clamping and long-term stability are mandatory.
FAQ
What is the clamping voltage of the SMAJ12AHM3/I at its rated peak pulse current?
The SMAJ12AHM3/I has a maximum clamping voltage (VC) of 19.9 V at its rated peak pulse current (IPPM) of 20.1 A under a 10/1000 μs waveform. This value is measured per standard test conditions and defines the upper voltage limit imposed on protected circuitry during surge events. The SMAJ12AHM3/I maintains this clamping performance across its specified operating temperature range and is validated for repetitive surge duty cycles up to 0.01 %.
Is the SMAJ12AHM3/I qualified for automotive applications?
Yes, the SMAJ12AHM3/I is AEC-Q101 qualified, as confirmed by Vishay's ordering code structure (HM3 suffix denotes halogen-free, RoHS-compliant, and AEC-Q101 qualified). This qualification covers stress tests including temperature cycling, high-temperature reverse bias, and ESD, making the SMAJ12AHM3/I suitable for use in automotive electronic control units, body electronics, and infotainment systems where reliability under extreme thermal and electrical conditions is required.
What does the "HM3" suffix mean in SMAJ12AHM3/I?
The "HM3" suffix in SMAJ12AHM3/I indicates halogen-free, RoHS-compliant construction with AEC-Q101 qualification. Specifically, "H" denotes AEC-Q101 qualification, "M" signifies halogen-free molding compound and plating, and "3" confirms RoHS compliance per EU Directive 2011/65/EU. The trailing "I" specifies packaging in 13-inch tape-and-reel format with I-packaging code for traceability. This distinguishes it from E3 (RoHS only) or HE3 (AEC-Q101 + RoHS, not halogen-free) variants.
Can SMAJ12AHM3/I be used in bidirectional configurations?
No, SMAJ12AHM3/I is a unidirectional TVS diode, as indicated by the "A" (not "CA") suffix and presence of cathode band marking. Bidirectional operation requires the "CA" suffix (e.g., SMAJ12CA). Using SMAJ12AHM3/I in reverse-biased signal paths without proper polarity alignment will result in forward conduction and potential failure. For symmetric transient protection on AC lines or differential pairs, select a CA-series part instead.
What is the thermal resistance and recommended PCB layout for SMAJ12AHM3/I?
The SMAJ12AHM3/I has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W, measured with 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal. To achieve rated power dissipation and avoid thermal runaway, the PCB must implement these minimum pad dimensions with adequate copper pour and thermal vias if ambient temperatures exceed 50 °C. The device is rated for MSL Level 1 and withstands peak reflow temperatures up to 260 °C, compatible with standard lead-free SMT processes.
SMAJ12AHM3/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:
- Discontinued at Digi-Key
- 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:
- 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)
SMAJ12AHM3/I FAQ
1.How can I place an order for SMAJ12AHM3/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ12AHM3/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 SMAJ12AHM3/I reliable?
The price and inventory of SMAJ12AHM3/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ12AHM3/I is usually 5 days.
3.What payment methods are accepted for SMAJ12AHM3/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ12AHM3/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ12AHM3/I?
SMAJ12AHM3/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ12AHM3/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 SMAJ12AHM3/I?
For technical support, including SMAJ12AHM3/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ12AHM3/I requirements.
6.How does Aetrix verify that SMAJ12AHM3/I is sourced from the original manufacturer or authorized distributors?
All SMAJ12AHM3/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 SMAJ12AHM3/I meets industry standards.
7.What is the process for return or replacement of SMAJ12AHM3/I?
All SMAJ12AHM3/I units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ12AHM3/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 SMAJ12AHM3/I part is unused and in its original packaging.
Return procedure for SMAJ12AHM3/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ12AHM3/I Tags
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