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Vishay General Semiconductor - Diodes Division SMAJ18AHE3/61
- Part No.:
- SMAJ18AHE3/61
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ18AHE3/61.pdf
- Description:
- TVS DIODE 18VWM 29.2VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:9,356
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Product details
Overview
SMAJ18AHE3/61 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, and 400 W peak pulse power rating with 10/1000 μs waveform - deployed on power rails and signal lines in automotive ECUs and industrial sensor interfaces.
For engineers reviewing the SMAJ18AHE3/61 datasheet, SMAJ18AHE3/61 pinout, SMAJ18AHE3/61 application, or SMAJ18AHE3/61 equivalent, key selection criteria include its AEC-Q101 qualification, low clamping ratio (VC/VBR ≈ 1.35), 1.0 μA max reverse leakage at VWM, and compatibility with automated SMT placement on 0.2" × 0.2" copper pads.
Technical Context
This unidirectional TVS diode operates as a voltage-clamped shunt protector: under normal conditions it presents high impedance (<1.0 μA leakage at 18 V), then rapidly avalanches to clamp transients above ~20 V. Its glass-passivated junction ensures stable breakdown and low incremental surge resistance, enabling consistent clamping performance across repetitive 10/1000 μs surges at 0.01% duty cycle.
Thermally, it exhibits RθJA = 120 °C/W (on recommended pad layout) and RθJL = 30 °C/W, supporting reliable operation up to TJ = +150 °C. The cathode-band-marked SMA package meets MSL Level 1 and JESD 201 Class 2 whisker resistance, with matte tin-plated leads solderable per J-STD-002.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - Maximum continuous reverse operating voltage before significant leakage; defines safe DC/AC working range. |
| VBR (min/max) | 20.0 V / 22.1 V at IT = 1 mA - Ensures predictable avalanche initiation within tight tolerance for precise protection thresholding. |
| VC @ IPPM | 29.2 V at 13.7 A - Clamping voltage during 400 W transient; limits downstream voltage stress to ≤29.2 V under worst-case surge. |
| IPPM | 13.7 A - Peak pulse current capability with 10/1000 μs waveform; determines survivability against IEC 61000-4-5 Level 4 surges. |
| PPPM | 400 W - Peak pulse power rating; enables protection of 12 V/24 V systems against lightning-induced and inductive-switching transients. |
| TJ max. | +150 °C - Maximum junction temperature; supports under-hood automotive use and high-ambient industrial environments. |
| Leakage ID | ≤1.0 μA at VWM - Minimal standby power loss and negligible loading on protected circuits during normal operation. |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, low-profile case with molded epoxy body meeting UL 94 V-0; cathode identified by a single band on the case end.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry terminal during forward conduction (unidirectional only) | Connected to system ground or lower-potential rail; forms shunt path when transient exceeds VBR. |
| Cathode | Current exit terminal during avalanche clamping | Connected to protected line (e.g., 12 V supply or CAN_H); polarity marking critical for correct installation. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD testing - suitable for engine control, ADAS, and infotainment modules. |
| 400 W peak pulse power (10/1000 μs) | Withstands IEC 61000-4-5 combination wave surges up to 4 kV (open-circuit)/2 kA (short-circuit) without degradation. |
| Low clamping ratio (VC/VBR ≈ 1.35) | Minimizes overvoltage overshoot during clamping - protects downstream ICs with 30 V absolute maximum ratings. |
| MSL Level 1, 260 °C reflow compatible | Enables standard lead-free SMT assembly without moisture sensitivity concerns or baking requirements. |
| Glass-passivated junction | Provides stable VBR tolerance, low leakage drift over time, and immunity to humidity-induced parameter shift. |
Applications
| Automotive Power Rail Protection | Industrial Sensor Signal Line Protection |
|---|---|
Use Scenario: 12 V battery-supplied microcontroller power input in vehicle body control module exposed to load-dump and jump-start transients. IC Role / Device Role / Timing Role: Unidirectional shunt TVS placed between VIN and GND to clamp surges >20 V while maintaining <1 μA leakage during nominal operation. Use Value: Limits transient voltage to ≤29.2 V, preventing damage to 3.3 V/5 V LDOs and MCU I/O pins rated to 30 V absolute maximum. |
Use Scenario: Analog output line (0–10 V) from pressure sensor in factory automation PLC, subject to EFT bursts and cable coupling noise. IC Role / Device Role / Timing Role: TVS connected across signal and ground to absorb fast-rising transients before they reach ADC input stage. Use Value: Sub-1 ns response time and 29.2 V clamping protect 12-bit SAR ADC front-end from latch-up or parametric shift during 1 kV EFT events. |
| Consumer USB Port ESD Protection | Telecom DC Power Input Protection |
Use Scenario: VBUS line of USB 2.0 port in smart home hub, requiring IEC 61000-4-2 ±15 kV contact ESD suppression. IC Role / Device Role / Timing Role: Primary shunt protector upstream of USB switch IC, leveraging low capacitance (<100 pF) and fast avalanche turn-on. Use Value: Clamps ESD pulses to <30 V within <1 ns, preserving signal integrity and preventing gate oxide rupture in USB transceivers. |
Use Scenario: -48 V DC input of telecom base station power supply subjected to lightning-induced surges on outdoor cabling. IC Role / Device Role / Timing Role: Secondary protection device after gas discharge tube (GDT), providing precise low-voltage clamping for downstream DC/DC converters. Use Value: 400 W pulse rating and 29.2 V clamping enable coordination with upstream GDT to limit let-through energy to <10 mJ. |
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), identical electrical specs and SMA package | Lacks automotive qualification; unsuitable for under-hood or safety-critical ECUs | Select when cost-sensitive industrial or consumer designs do not require automotive reliability validation. |
| SMBJ18AHE3/61 | Same VWM/VBR/VC, but SMB (DO-214AA) package - 25% larger footprint, 50% higher PPPM (600 W) | Higher surge margin and thermal mass; requires PCB area increase and different pad layout | Choose when system-level surge testing exceeds 400 W or board space allows larger package for enhanced ruggedness. |
Compared with SMAJ18AHE3/61, SMAJ18A-E3/61 offers identical protection performance at lower cost but no automotive qualification, while SMBJ18AHE3/61 provides 50% higher surge capacity in a physically larger package - enabling trade-offs between qualification, board area, and surge margin.
Availability
SMAJ18AHE3/61 is available at Aetrix Electronics and suitable for automotive electronic control units, industrial sensor interfaces, and telecom power input stages requiring stable component supply with AEC-Q101 assurance and full traceability.
Supply support for SMAJ18AHE3/61 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 diodes, MOSFETs, optoelectronics, and passive components with emphasis on reliability, efficiency, and application-specific optimization.
The SMAJ series is engineered for high-reliability transient suppression in harsh environments - targeting automotive, industrial, and telecom applications where robustness against ESD, EFT, and lightning surges is mandatory.
FAQ
What is the clamping voltage of SMAJ18AHE3/61 at its rated peak pulse current?
The SMAJ18AHE3/61 has a maximum clamping voltage (VC) of 29.2 V at its rated peak pulse current (IPPM) of 13.7 A, measured with a 10/1000 μs waveform. This value ensures protected circuits remain below critical voltage thresholds during surge events. The clamping performance is guaranteed across the full operating temperature range and is validated per AEC-Q101 stress tests for SMAJ18AHE3/61.
Is SMAJ18AHE3/61 suitable for automotive applications?
Yes, SMAJ18AHE3/61 is AEC-Q101 qualified and specifically intended for automotive use - including engine control units, body electronics, and ADAS sensors. Its construction includes glass-passivated junctions, MSL Level 1 reflow compatibility, and extended temperature operation from –55 °C to +150 °C. The "HE3" suffix denotes RoHS-compliant and AEC-Q101 qualified version of SMAJ18AHE3/61.
How does the leakage current of SMAJ18AHE3/61 compare to similar TVS diodes?
SMAJ18AHE3/61 specifies a maximum reverse leakage current (ID) of 1.0 μA at its 18 V stand-off voltage (VWM), which is typical for high-reliability unidirectional TVS diodes in the SMAJ family. This low leakage avoids unnecessary power drain in always-on automotive modules and prevents signal distortion on precision analog lines - a key differentiator versus older-generation TVS devices with >5 μA leakage at same VWM.
What is the thermal resistance of SMAJ18AHE3/61, and how does it affect PCB layout?
SMAJ18AHE3/61 has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W when mounted on the recommended 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal. To maintain TJ ≤ 150 °C under 3.3 W steady-state dissipation, designers must ensure adequate copper area and avoid excessive trace length. The RθJL of 30 °C/W confirms efficient heat transfer to PCB copper, making SMAJ18AHE3/61 suitable for compact layouts with moderate thermal loads.
Can SMAJ18AHE3/61 be used in bidirectional configurations?
No, SMAJ18AHE3/61 is a unidirectional TVS diode, indicated by the "A" suffix and cathode band marking. For bidirectional protection, Vishay offers the SMAJ18CA series (e.g., SMAJ18CAHE3/61), which provides symmetrical clamping in both polarities. Using SMAJ18AHE3/61 in reverse-biased configuration risks permanent damage due to lack of reverse breakdown specification - always verify polarity during placement of SMAJ18AHE3/61.
SMAJ18AHE3/61 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AC, SMA
- Series:
- TransZorb®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- 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)
SMAJ18AHE3/61 FAQ
1.How can I place an order for SMAJ18AHE3/61 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ18AHE3/61 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 SMAJ18AHE3/61 reliable?
The price and inventory of SMAJ18AHE3/61 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ18AHE3/61 is usually 5 days.
3.What payment methods are accepted for SMAJ18AHE3/61?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ18AHE3/61 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ18AHE3/61?
SMAJ18AHE3/61 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ18AHE3/61 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 SMAJ18AHE3/61?
For technical support, including SMAJ18AHE3/61 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ18AHE3/61 requirements.
6.How does Aetrix verify that SMAJ18AHE3/61 is sourced from the original manufacturer or authorized distributors?
All SMAJ18AHE3/61 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 SMAJ18AHE3/61 meets industry standards.
7.What is the process for return or replacement of SMAJ18AHE3/61?
All SMAJ18AHE3/61 units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ18AHE3/61, 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 SMAJ18AHE3/61 part is unused and in its original packaging.
Return procedure for SMAJ18AHE3/61:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ18AHE3/61 Tags
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