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Vishay General Semiconductor - Diodes Division SMAJ18HE3/61
- Part No.:
- SMAJ18HE3/61
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ18HE3/61.pdf
- Description:
- TVS DIODE 18VWM 32.2VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:3,212
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Product details
Overview
SMAJ18HE3/61 from Vishay General Semiconductor is a high-reliability, AEC-Q101-qualified unidirectional transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, designed for automotive and industrial overvoltage protection. It features 18 V stand-off voltage (VWM), 32.2 V maximum clamping voltage (VC) at 12.4 A peak pulse current (IPPM), and 400 W peak pulse power (10/1000 µs waveform). It protects MOSFETs, ICs, and sensor signal lines against inductive switching transients and ESD.
For engineers reviewing the SMAJ18HE3/61 datasheet, SMAJ18HE3/61 pinout, SMAJ18HE3/61 application, or SMAJ18HE3/61 equivalent, this page delivers verified electrical parameters, automotive-grade qualification status, thermal resistance values (RθJA = 120 °C/W), junction-to-lead thermal path, and precise clamping behavior under standardized surge conditions.
Technical Context
The SMAJ18HE3/61 operates as a unidirectional avalanche diode with cathode-band polarity marking, optimized for fast response (<1 ps) to transient events. Its glass-passivated junction ensures stable breakdown characteristics and low incremental surge resistance, enabling consistent clamping performance across repetitive 10/1000 µs surges at 0.01% duty cycle.
Rated for -55 °C to +150 °C operating junction temperature, it supports high-reliability automotive environments per AEC-Q101. The device is mounted on 0.2 × 0.2 inch copper pads, delivering 400 W peak pulse power below 78 V - derated linearly above 25 °C per Fig. 2 of document 88390.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - Maximum continuous reverse working voltage before clamping begins; defines safe operating margin for 15–18 V rail protection. |
| VC @ IPPM | 32.2 V - Clamped voltage at 12.4 A surge; limits downstream voltage stress during 400 W transient events. |
| IPPM | 12.4 A - Peak pulse current supported with 10/1000 µs waveform; determines minimum trace width and PCB layout robustness. |
| RθJA | 120 °C/W - Junction-to-ambient thermal resistance; requires adequate copper area (0.2 × 0.2") to maintain TJ ≤ 150 °C under full power. |
| TJ max. | +150 °C - Maximum junction temperature; enables operation in under-hood automotive environments without derating. |
| IFSM | 40 A - Non-repetitive forward surge rating (8.3 ms half-sine); supports inrush or fault-current handling in DC power paths. |
| Leakage @ VWM | 1.0 µA - Reverse leakage at 18 V; negligible loading on 18 V bias networks or high-impedance sensor interfaces. |
Pinout & Package
Package: DO-214AC (SMA), surface-mount, RoHS-compliant, matte tin-plated leads, MSL Level 1 (260 °C reflow).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential side (e.g., GND or return path); conducts during forward surge events (e.g., reverse-battery protection). |
| Cathode (banded end) | Avalanche clamping terminal | Connected to protected line (e.g., 12 V supply or CAN bus); initiates clamping when reverse voltage exceeds VWM. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive applications including engine control units and body electronics - no additional qualification testing required. |
| Glass-passivated junction | Ensures stable VBR tolerance (min 20.0 V, max 24.4 V) and long-term reliability under thermal cycling and humidity exposure. |
| Low incremental surge resistance | Minimizes VC overshoot during fast-rising transients (e.g., ISO 7637-2 Pulse 1/2a), improving system-level immunity margin. |
| MSL Level 1 compliance | Supports standard SMT reflow profiles up to 260 °C peak without preconditioning - simplifies manufacturing integration. |
| 400 W peak pulse power (≤78 V) | Provides robust protection against load-dump and inductive kick events in 12 V systems without external series impedance. |
Applications
| Automotive Power Rail Protection | Industrial Sensor Interface Protection |
|---|---|
|
Use Scenario: Protecting 12 V power distribution networks in ECUs against load dump (ISO 16750-2) and alternator transients. IC Role / Device Role / Timing Role: Unidirectional TVS placed between battery rail and point-of-load regulator input. Use Value: Clamps to 32.2 V at 12.4 A, limiting downstream voltage stress below 36 V - within absolute maximum ratings of most automotive LDOs and microcontrollers. |
Use Scenario: Safeguarding analog outputs (e.g., 4–20 mA transmitter lines) from field-induced surges in factory automation. IC Role / Device Role / Timing Role: Bidirectional-capable unidirectional TVS (cathode to signal, anode to ground) on current-loop output stage. Use Value: 1.0 µA leakage at 18 V avoids calibration drift; 32.2 V clamping prevents op-amp saturation and ADC overrange in connected PLC inputs. |
| Motor Drive Gate Driver Protection | Automotive Lighting Module Protection |
|
Use Scenario: Shielding high-side N-channel MOSFET gate drivers from Miller-induced voltage spikes during fast switching. IC Role / Device Role / Timing Role: TVS placed between gate and source, referenced to local driver ground. Use Value: Sub-nanosecond response time ensures clamping activation before gate oxide breakdown; 40 A IFSM withstands repeated gate ringing energy. |
Use Scenario: Suppressing transients generated by relay-controlled headlamp or foglight circuits in vehicle lighting modules. IC Role / Device Role / Timing Role: Unidirectional TVS on switched 12 V feed to LED driver ICs. Use Value: AEC-Q101 qualification guarantees lifetime reliability under thermal shock and vibration; 32.2 V clamping prevents LED driver latch-up during 200 V/100 ms load dump pulses. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ18A-E3/61 | Commercial-grade (non-AEC-Q101), same VWM/VC/IPPM, identical DO-214AC package and pinout. | Lacks automotive qualification; suitable for industrial/commercial designs where AEC compliance is not mandated. | Select SMAJ18A-E3/61 only if automotive qualification is unnecessary and cost sensitivity outweighs long-term reliability requirements. |
| SMBJ18HE3/61 | Same AEC-Q101 grade, but SMB package (DO-214AA); 600 W peak pulse power (10/1000 µs), higher IPPM (21.3 A), larger footprint. | Higher power handling enables use in 24 V systems or where longer surge duration must be absorbed without degradation. | Choose SMBJ18HE3/61 when system-level surge testing exceeds 400 W or when board space allows larger SMB footprint for enhanced thermal margin. |
Compared with SMAJ18HE3/61, SMAJ18A-E3/61 offers identical electrical protection but lacks automotive qualification, while SMBJ18HE3/61 provides 50% higher surge power rating in a physically larger package - enabling extended lifetime in harsher transient environments without changing circuit topology.
Availability
SMAJ18HE3/61 is available at Aetrix Electronics and suitable for automotive ECU design, industrial sensor interface development, and motor drive gate protection requiring stable component supply and guaranteed AEC-Q101 compliance.
Supply support for SMAJ18HE3/61 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 high-reliability diodes, MOSFETs, and passive components for automotive, industrial, and computing markets.
The SMAJ family targets high-volume, space-constrained transient protection in automotive power systems and industrial control - emphasizing AEC-Q101 qualification, tight parametric consistency, and robust thermal performance in DO-214AC packaging.
FAQ
What is the breakdown voltage range of the SMAJ18HE3/61?
The SMAJ18HE3/61 has a minimum breakdown voltage (VBR) of 20.0 V and a maximum of 24.4 V at 1.0 mA test current, per Vishay document 88390. This 20–24.4 V range ensures reliable avalanche initiation above its 18 V stand-off voltage while maintaining margin against false triggering during normal operation. The SMAJ18HE3/61's specified VBR window is validated per AEC-Q101 stress testing.
Is SMAJ18HE3/61 suitable for bi-directional transient protection?
No - SMAJ18HE3/61 is a unidirectional TVS diode, indicated by the absence of "C" or "CA" suffix and confirmed by its cathode band marking. For bi-directional protection at 18 V, use SMAJ18CA-E3/61 or SMAJ18C-E3/61. The SMAJ18HE3/61 clamps only in reverse bias; forward conduction occurs above ~3.5 V (VF at 25 A), making it unsuitable for AC-coupled or symmetrical surge scenarios.
What does the "HE3" suffix signify in SMAJ18HE3/61?
The "HE3" suffix denotes high-reliability, automotive-grade construction: "H" indicates AEC-Q101 qualification and enhanced process controls; "E3" specifies RoHS-compliant, matte tin-plated leads meeting JESD201 Class 2 whisker resistance. This distinguishes SMAJ18HE3/61 from commercial "E3" variants (e.g., SMAJ18A-E3/61) and confirms its suitability for under-hood automotive applications.
How does the thermal resistance of SMAJ18HE3/61 affect PCB layout?
The SMAJ18HE3/61 has RθJA = 120 °C/W and RθJL = 30 °C/W. To prevent junction overheating during 400 W surges, Vishay mandates mounting on 0.2 × 0.2 inch (5.0 × 5.0 mm) copper pads per terminal. Reducing pad area increases thermal impedance, risking TJ > 150 °C and permanent degradation. The SMAJ18HE3/61's thermal design requires strict adherence to this pad layout for rated performance.
Can SMAJ18HE3/61 replace SMAJ18A-E3/61 in an existing design?
Yes - SMAJ18HE3/61 is a direct drop-in replacement for SMAJ18A-E3/61 in terms of pinout, package (DO-214AC), and electrical specs (VWM, VC, IPPM). The only functional difference is AEC-Q101 qualification: SMAJ18HE3/61 adds automotive reliability validation without altering circuit behavior. Using SMAJ18HE3/61 improves field failure resilience in automotive deployments while maintaining full compatibility with SMAJ18A-E3/61 layouts.
SMAJ18HE3/61 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AC, SMA
- Series:
- TransZorb®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 18V
- Voltage - Breakdown (Min):
- 20V
- Voltage - Clamping (Max) @ Ipp:
- 32.2V
- Current - Peak Pulse (10/1000µs):
- 12.4A
- 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)
SMAJ18HE3/61 FAQ
1.How can I place an order for SMAJ18HE3/61 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ18HE3/61 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 SMAJ18HE3/61 reliable?
The price and inventory of SMAJ18HE3/61 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ18HE3/61 is usually 5 days.
3.What payment methods are accepted for SMAJ18HE3/61?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ18HE3/61 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ18HE3/61?
SMAJ18HE3/61 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ18HE3/61 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 SMAJ18HE3/61?
For technical support, including SMAJ18HE3/61 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ18HE3/61 requirements.
6.How does Aetrix verify that SMAJ18HE3/61 is sourced from the original manufacturer or authorized distributors?
All SMAJ18HE3/61 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 SMAJ18HE3/61 meets industry standards.
7.What is the process for return or replacement of SMAJ18HE3/61?
All SMAJ18HE3/61 units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ18HE3/61, 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 SMAJ18HE3/61 part is unused and in its original packaging.
Return procedure for SMAJ18HE3/61:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ18HE3/61 Tags
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