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Vishay General Semiconductor - Diodes Division SMAJ18AHE3_A/H
- Part No.:
- SMAJ18AHE3_A/H
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ18AHE3_A/H.pdf
- Description:
- TVS DIODE 18VWM 29.2VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:4,121
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Product details
Overview
SMAJ18AHE3_A/H from Vishay General Semiconductor is a unidirectional transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, designed for robust overvoltage protection of sensitive electronics. It features a 18 V stand-off 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 (10/1000 μs waveform), commonly deployed on power rails and I/O lines of automotive ECUs and industrial sensor interfaces.
For engineers reviewing the SMAJ18AHE3_A/H datasheet, SMAJ18AHE3_A/H pinout, SMAJ18AHE3_A/H application, or SMAJ18AHE3_A/H equivalent, key selection criteria include clamping performance under 10/1000 μs transients, AEC-Q101 qualification status, unidirectional polarity marking, thermal resistance (RθJA = 120 °C/W), and compatibility with automated SMT placement on standard PCB pad layouts.
Technical Context
This TVS diode operates as a voltage-clamping device triggered by reverse-biased avalanche breakdown, providing low-impedance shunt path during ESD or lightning-induced surges. Its glass-passivated junction ensures stable VBR tolerance and long-term reliability, while the unidirectional configuration enables cathode-referenced protection on positive-rail circuits.
The SMAJ18AHE3_A/H is rated for 40 A non-repetitive forward surge current (IFSM, 8.3 ms half-sine), supports operating junction temperatures from –55 °C to +150 °C, and meets MSL Level 1 per J-STD-020 with 260 °C peak reflow profile - confirming suitability for high-volume automotive and industrial reflow assembly.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM (Stand-off Voltage) | 18 V - Maximum continuous reverse voltage before significant leakage; defines safe operating margin below clamping threshold. |
| VBR (Breakdown Voltage) | 20.0–22.1 V at 1 mA - Avalanche onset range; ensures predictable turn-on during transients without premature conduction. |
| VC (Clamping Voltage) | 29.2 V at IPPM = 13.7 A - Peak voltage seen by protected circuit during 10/1000 μs surge; critical for IC-level survivability. |
| PPPM (Peak Pulse Power) | 400 W (10/1000 μs) - Surge energy handling capacity; derates to 300 W above 78 V, but SMAJ18AHE3_A/H remains at full 400 W rating. |
| ID (Reverse Leakage) | 1.0 μA at VWM - Ultra-low leakage preserves system power integrity in battery-powered or low-quiescent-current designs. |
| TJ max. | +150 °C - Enables operation in under-hood automotive environments and thermally constrained industrial enclosures. |
| AEC-Q101 Qualified | Yes - Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD testing per AEC specification. |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, low-profile case with matte tin-plated leads solderable per J-STD-002 and JESD 22-B102. Polarity marked by cathode band on unidirectional devices.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward current entry / Surge return path | Connected to ground or lower-potential rail; completes clamping loop during transient events. |
| Cathode | Protected line connection / Surge sink | Connected to line being protected (e.g., 12 V supply); avalanche conduction occurs when voltage exceeds VBR. |
Key Features
| Feature | Design Value |
|---|---|
| 400 W peak pulse power (10/1000 μs) | Enables protection against ISO 7637-2 Pulse 1/2a/5a and IEC 61000-4-5 Level 4 surges without derating. |
| AEC-Q101 qualified (HE3 suffix) | Confirms automotive-grade qualification including HTOL, TC, and ESD robustness - required for Tier-1 ECU designs. |
| Low incremental surge resistance | Minimizes voltage overshoot during fast-rising transients (<1 ns response), improving protection fidelity for high-speed interfaces. |
| MSL Level 1, 260 °C peak reflow | Eliminates moisture sensitivity concerns and allows direct placement into standard lead-free reflow profiles without baking. |
| Glass passivated junction | Ensures stable VBR over lifetime and immunity to humidity-induced parameter drift in harsh environments. |
Applications
| Automotive Body Control Module (BCM) | Industrial PLC Digital Input Card |
|---|---|
|
Use Scenario: Protects 12 V supply rail and LIN bus interface from load-dump and inductive switching transients in vehicle body electronics. IC Role / Device Role / Timing Role: Unidirectional TVS clamp placed between power rail and chassis ground to limit voltage excursions during ISO 7637-2 Pulse 5a events. Use Value: Clamps to ≤29.2 V at 13.7 A, ensuring downstream LDOs and microcontrollers remain within absolute maximum ratings during 12 V system surges. |
Use Scenario: Shields 24 V digital input channels from field-wiring induced surges in factory automation control cabinets. IC Role / Device Role / Timing Role: Standoff-rated TVS on each optocoupler input leg to absorb repetitive 1 kV/500 A transients per IEC 61000-4-5. Use Value: 1.0 μA leakage at 18 V prevents false triggering of high-impedance input comparators during normal operation. |
| Automotive Infotainment Power Supply | Consumer IoT Sensor Hub |
|
Use Scenario: Guards USB-C PD controller VBUS line against hot-plug and ESD events in head-unit power management. IC Role / Device Role / Timing Role: Fast-response unidirectional clamp referenced to system ground, placed upstream of buck converter input capacitor. Use Value: 29.2 V clamping voltage ensures USB PD PHY ICs (rated to 30 V abs max) survive repeated 8 kV contact ESD per IEC 61000-4-2. |
Use Scenario: Safeguards battery-fed environmental sensor nodes (temperature/humidity) from electrostatic discharge during handling and installation. IC Role / Device Role / Timing Role: Low-leakage TVS on coin-cell supply line to prevent ESD-induced brownout resets in ultra-low-power MCUs. Use Value: RθJA = 120 °C/W and 150 °C TJ max enable reliable operation inside sealed plastic enclosures with no forced airflow. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ18A-E3/61 | Commercial-grade (non-AEC-Q101), same VWM/VBR/VC specs, identical SMA package and pinout. | Lacks automotive qualification; suitable for consumer/industrial use where AEC compliance is not mandated. | Select SMAJ18AHE3_A/H when automotive qualification, traceable sourcing, or extended temperature validation is required. |
| SMBJ18AHE3_A/H | Same AEC-Q101 qualification and electrical specs, but SMB (DO-214AA) package - 2.5 mm wider, higher thermal mass. | Higher 600 W PPPM rating and lower RθJA (90 °C/W); preferred where surge energy exceeds 400 W or board space permits larger footprint. | Choose SMAJ18AHE3_A/H for space-constrained layouts requiring 400 W protection; select SMBJ18AHE3_A/H for enhanced thermal margin or higher-energy transients. |
Compared with SMAJ18A-E3/61, SMAJ18AHE3_A/H adds AEC-Q101 qualification and automotive traceability; compared with SMBJ18AHE3_A/H, it trades 200 W pulse power headroom and thermal performance for 30 % smaller PCB area in the SMA footprint.
Availability
SMAJ18AHE3_A/H is available at Aetrix Electronics and suitable for automotive electronic control units, industrial programmable logic controllers, and consumer IoT sensor hubs requiring stable component supply across multi-year production cycles.
Supply support for SMAJ18AHE3_A/H 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 automotive, industrial, and telecom infrastructure - delivering consistent clamping behavior and AEC-Q101 validation for mission-critical power and signal line protection.
FAQ
What is the clamping voltage of SMAJ18AHE3_A/H at its rated peak pulse current?
The SMAJ18AHE3_A/H has a maximum clamping voltage (VC) of 29.2 V at 13.7 A peak pulse current (IPPM), measured under the standardized 10/1000 μs double-exponential surge waveform. This value is guaranteed across the full operating temperature range and confirms that protected circuitry remains within safe voltage limits during transient events. The SMAJ18AHE3_A/H achieves this clamping performance while maintaining low leakage and fast response.
Is SMAJ18AHE3_A/H qualified for automotive applications?
Yes, SMAJ18AHE3_A/H is AEC-Q101 qualified, as indicated by the "HE3" suffix in its part number. This certification covers stress tests including high-temperature operating life, temperature cycling, and ESD robustness - validating its suitability for under-hood and cabin electronics in passenger vehicles and commercial vehicles. The SMAJ18AHE3_A/H is explicitly listed in Vishay's AEC-Q101 qualified devices table.
What does the "A/H" suffix in SMAJ18AHE3_A/H signify?
The "A/H" suffix in SMAJ18AHE3_A/H denotes the packaging configuration: "H" indicates a 7-inch diameter plastic tape-and-reel format with 1800 units per reel, and "A" specifies the revision code per Vishay's internal documentation. This ordering code aligns with Vishay's preferred package code system shown in the datasheet's Ordering Information table, ensuring correct logistics and assembly handling for SMAJ18AHE3_A/H.
How does SMAJ18AHE3_A/H compare to bidirectional TVS diodes like SMAJ18CA?
SMAJ18AHE3_A/H is unidirectional and features a cathode band for polarity identification, whereas SMAJ18CA is bidirectional with no polarity marking and symmetrical breakdown in both directions. The SMAJ18AHE3_A/H offers tighter leakage control (1.0 μA at 18 V) versus SMAJ18CA's higher ID limit, making it preferable for DC rail protection. SMAJ18AHE3_A/H cannot replace SMAJ18CA in AC-coupled or floating signal line applications without circuit redesign.
What is the thermal resistance of SMAJ18AHE3_A/H, and how does it affect PCB layout?
The SMAJ18AHE3_A/H has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W when mounted on the minimum recommended 0.2" × 0.2" copper pads per terminal. This value assumes standard FR-4 PCB construction without additional thermal vias or heatsinking. To maintain junction temperature below 150 °C during repetitive surges, designers should adhere to Vishay's specified pad layout and avoid excessive trace length or narrow routing near the SMAJ18AHE3_A/H terminals.
SMAJ18AHE3_A/H 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:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ18AHE3_A/H FAQ
1.How can I place an order for SMAJ18AHE3_A/H through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ18AHE3_A/H 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 SMAJ18AHE3_A/H reliable?
The price and inventory of SMAJ18AHE3_A/H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ18AHE3_A/H is usually 5 days.
3.What payment methods are accepted for SMAJ18AHE3_A/H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ18AHE3_A/H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ18AHE3_A/H?
SMAJ18AHE3_A/H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ18AHE3_A/H 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 SMAJ18AHE3_A/H?
For technical support, including SMAJ18AHE3_A/H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ18AHE3_A/H requirements.
6.How does Aetrix verify that SMAJ18AHE3_A/H is sourced from the original manufacturer or authorized distributors?
All SMAJ18AHE3_A/H 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 SMAJ18AHE3_A/H meets industry standards.
7.What is the process for return or replacement of SMAJ18AHE3_A/H?
All SMAJ18AHE3_A/H units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ18AHE3_A/H, 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 SMAJ18AHE3_A/H part is unused and in its original packaging.
Return procedure for SMAJ18AHE3_A/H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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