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Vishay General Semiconductor - Diodes Division SMAJ18AHM3_A/I
- Part No.:
- SMAJ18AHM3_A/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ18AHM3_A/I.pdf
- Description:
- TVS DIODE 18VWM 29.2VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:2,569
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Product details
Overview
SMAJ18AHM3_A/I from Vishay General Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, designed for clamping fast-rising ESD and surge transients on power and signal lines. It features 18 V standoff voltage (VWM), 20.0–22.1 V breakdown voltage (VBR) at 1 mA, 29.2 V maximum clamping voltage (VC) at 13.7 A peak pulse current (IPPM), and 400 W peak pulse power rating with 10/1000 μs waveform - used to protect MOSFETs, ICs, and sensor interfaces in automotive and industrial control systems.
For engineers reviewing the SMAJ18AHM3_A/I datasheet, SMAJ18AHM3_A/I pinout, SMAJ18AHM3_A/I application, or SMAJ18AHM3_A/I equivalent, this device is selected for robust overvoltage protection where low clamping voltage, fast response (<1 ns), and AEC-Q101 qualification (via HM3 suffix) are required in space-constrained PCB layouts.
Technical Context
The SMAJ18AHM3_A/I operates as a unidirectional avalanche diode, conducting only when reverse voltage exceeds its breakdown threshold (VBR = 20.0–22.1 V), then clamping to ≤29.2 V at 13.7 A. Its glass-passivated junction ensures stable leakage (<1.0 μA at VWM) and repeatable surge performance under repetitive transients.
Thermally, it exhibits RθJA = 120 °C/W and RθJL = 30 °C/W, requiring minimum 5.0 mm × 5.0 mm copper pads per terminal for full 400 W rating. The HM3 suffix confirms halogen-free, RoHS-compliant, and AEC-Q101 qualified construction - validated for automotive-grade reliability per JESD22-B102 whisker testing and MSL Level 1 reflow (260 °C peak).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - maximum continuous reverse operating voltage before conduction begins; defines safe DC/AC working range. |
| VBR (min/max) | 20.0 V / 22.1 V at IT = 1 mA - guaranteed avalanche onset window; ensures consistent triggering across production lots. |
| VC @ IPPM | 29.2 V at 13.7 A - clamped voltage during 10/1000 μs surge; determines protected circuit's maximum transient stress level. |
| PPPM | 400 W - peak pulse power handling with 10/1000 μs waveform; enables protection against IEC 61000-4-5 Level 4 surges. |
| ID @ VWM | ≤1.0 μA - ultra-low reverse leakage at 18 V; minimizes standby power loss in battery-powered systems. |
| TJ max. | +150 °C - maximum junction temperature; supports operation in under-hood automotive environments. |
| Package | SMA (DO-214AC) - industry-standard surface-mount outline with 0.208" x 0.157" footprint; compatible with automated pick-and-place. |
Pinout & Package
Package: SMA (DO-214AC), molded plastic case with matte tin-plated leads; polarity indicated by cathode band on unidirectional devices.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward current entry / low-side reference | Connected to ground or lower-potential rail; forms return path during clamping. |
| Cathode | Reverse voltage sensing / clamping node | Connected to protected line (e.g., 12 V supply or CAN_H); conducts when Vline > VBR. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified (HM3 suffix) | Validated for automotive electronics per stress test requirements - enables use in ADAS, body control modules, and infotainment without additional qualification. |
| 400 W peak pulse power (10/1000 μs) | Withstands high-energy transients such as load dump (ISO 7637-2 Pulse 5a) and EFT bursts without degradation. |
| Low clamping ratio (VC/VBR ≈ 1.4) | Minimizes voltage overshoot during clamping - critical for protecting 24 V-rated logic inputs and gate drivers. |
| MSL Level 1, 260 °C peak reflow | Supports standard lead-free SMT assembly without moisture sensitivity concerns or baking requirements. |
| Halogen-free & RoHS-compliant | Meets environmental compliance mandates for global automotive and industrial OEMs without compromising surge performance. |
Applications
| Automotive Power Rail Protection | Industrial Sensor Interface Protection |
|---|---|
|
Use Scenario: Protecting 12 V/24 V power distribution networks in vehicle ECUs from load dump and alternator transients. IC Role / Device Role / Timing Role: Unidirectional TVS placed between power rail and chassis ground to clamp surges above 22.1 V. Use Value: Limits peak rail voltage to ≤29.2 V during ISO 7637-2 Pulse 5a events, preventing damage to downstream PMICs and microcontrollers. |
Use Scenario: Shielding analog input pins of industrial temperature/pressure sensors from ESD and field-induced transients. IC Role / Device Role / Timing Role: Low-capacitance TVS mounted directly at connector entry point to shunt fast transients before reaching ADC front-end. Use Value: Sub-1 ns response time and <1.0 μA leakage preserve signal integrity and measurement accuracy in 4–20 mA loop systems. |
| Motor Drive Gate Driver Protection | Telecom Line Card Surge Suppression |
|
Use Scenario: Safeguarding high-side N-channel MOSFET gate drivers in BLDC motor controllers from Miller-induced voltage spikes. IC Role / Device Role / Timing Role: TVS connected between gate and source to clamp dv/dt-induced overshoot exceeding VGS(max). Use Value: 29.2 V clamping voltage ensures gate oxide remains within 20 V absolute maximum rating, extending FET lifetime. |
Use Scenario: Front-end protection of Ethernet PHY or RS-485 transceivers in telecom base station line cards exposed to lightning-induced surges. IC Role / Device Role / Timing Role: Unidirectional TVS on VCC rail and bidirectional variants on data lines (e.g., SMAJ18CA) for comprehensive coverage. Use Value: 400 W rating meets IEC 61000-4-5 Level 4 (4 kV/2 Ω) requirements while maintaining low system-level capacitance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ18AHE3_A/I | Same electrical specs, but RoHS-compliant without halogen-free certification; no AEC-Q101 qualification. | Suitable for commercial/industrial use only; not approved for automotive under-hood deployment. | Select SMAJ18AHM3_A/I when halogen-free content and AEC-Q101 validation are mandatory per OEM spec. |
| SMBJ18A-M3/5A | Same VWM/VBR/VC, but SMB (DO-214AA) package - 25 % larger footprint and higher RθJA (140 °C/W). | Requires more PCB area and derating above 75 °C ambient; less suitable for dense automotive modules. | Choose SMAJ18AHM3_A/I for space-constrained designs needing identical protection in smaller SMA outline. |
Compared with SMAJ18AHE3_A/I and SMBJ18A-M3/5A, the SMAJ18AHM3_A/I uniquely combines halogen-free materials, AEC-Q101 qualification, and compact SMA packaging - making it the only option meeting Tier-1 automotive BOM requirements without layout or thermal compromise.
Availability
SMAJ18AHM3_A/I is available at Aetrix Electronics and suitable for automotive power rail protection, industrial sensor interface hardening, motor drive gate driver safeguarding, and telecom line card surge suppression requiring stable component supply across multi-year production cycles.
Supply support for SMAJ18AHM3_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, MOSFETs, optoelectronics, and passive components with emphasis on reliability and application-specific performance.
The SMAJ series is engineered for high-reliability transient suppression in harsh environments - targeting automotive, industrial, and telecom applications where surge immunity, long-term stability, and qualification compliance are non-negotiable.
FAQ
What is the clamping voltage of the SMAJ18AHM3_A/I under a 10/1000 μs surge?
The SMAJ18AHM3_A/I has a maximum clamping voltage (VC) of 29.2 V at 13.7 A peak pulse current (IPPM) with a 10/1000 μs waveform. This value is measured per IEC 61000-4-5 test conditions and ensures protected circuits experience minimal overvoltage stress during standardized surge events. The SMAJ18AHM3_A/I maintains this clamping performance across its rated temperature range and lifetime.
Is the SMAJ18AHM3_A/I suitable for automotive applications?
Yes - the SMAJ18AHM3_A/I carries the HM3 suffix, confirming it is halogen-free, RoHS-compliant, and AEC-Q101 qualified. It has passed stress tests including high-temperature operating life, temperature cycling, and unbiased highly accelerated stress testing (uHAST), making it approved for under-hood and chassis-mounted automotive electronics such as body control modules and ADAS power supplies.
How does the SMAJ18AHM3_A/I differ from the SMAJ18A-E3/61?
The SMAJ18AHM3_A/I differs from SMAJ18A-E3/61 in three key ways: it uses halogen-free molding compound (HM3 vs. E3), is AEC-Q101 qualified (not just commercial grade), and ships in 13" tape-and-reel (I-pack) versus 7" (61-pack). Electrically and dimensionally, both share identical VWM, VBR, VC, and SMA package - but only SMAJ18AHM3_A/I meets Tier-1 automotive material and reliability requirements.
What is the maximum reverse leakage current for the SMAJ18AHM3_A/I at its standoff voltage?
The SMAJ18AHM3_A/I specifies a maximum reverse leakage current (ID) of 1.0 μA at its 18 V standoff voltage (VWM), tested at TA = 25 °C. This ultra-low leakage preserves battery life in always-on automotive modules and avoids false triggering in high-impedance sensor bias networks. Leakage remains below 5 μA up to +125 °C per characterization data.
Can the SMAJ18AHM3_A/I be used in bidirectional configurations?
No - the SMAJ18AHM3_A/I is a unidirectional TVS diode, indicated by the "A" suffix and cathode band marking. For bidirectional protection, Vishay offers the SMAJ18CA variant, which provides symmetrical clamping in both polarities. Using SMAJ18AHM3_A/I in reverse-biased configurations risks permanent damage due to forward conduction beyond its 40 A IFSM rating.
SMAJ18AHM3_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:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 18V
- Voltage - Breakdown (Min):
- 20V
- Voltage - Clamping (Max) @ Ipp:
- 29.2V
- Current - Peak Pulse (10/1000µs):
- 13.7A
- 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)
SMAJ18AHM3_A/I FAQ
1.How can I place an order for SMAJ18AHM3_A/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ18AHM3_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 SMAJ18AHM3_A/I reliable?
The price and inventory of SMAJ18AHM3_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 SMAJ18AHM3_A/I is usually 5 days.
3.What payment methods are accepted for SMAJ18AHM3_A/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ18AHM3_A/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ18AHM3_A/I?
SMAJ18AHM3_A/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ18AHM3_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 SMAJ18AHM3_A/I?
For technical support, including SMAJ18AHM3_A/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ18AHM3_A/I requirements.
6.How does Aetrix verify that SMAJ18AHM3_A/I is sourced from the original manufacturer or authorized distributors?
All SMAJ18AHM3_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 SMAJ18AHM3_A/I meets industry standards.
7.What is the process for return or replacement of SMAJ18AHM3_A/I?
All SMAJ18AHM3_A/I units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ18AHM3_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 SMAJ18AHM3_A/I part is unused and in its original packaging.
Return procedure for SMAJ18AHM3_A/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ18AHM3_A/I Tags
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