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Vishay General Semiconductor - Diodes Division SMAJ18-E3/61
- Part No.:
- SMAJ18-E3/61
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ18-E3/61.pdf
- Description:
- TVS DIODE 18VWM 32.2VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:7,887
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Product details
Overview
SMAJ18-E3/61 from Vishay General Semiconductor is a unidirectional transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, designed for clamping inductive switching transients and ESD events on power and signal lines. It features 18 V stand-off voltage (VWM), 32.2 V maximum clamping voltage (VC) at 12.4 A peak pulse current (IPPM), 400 W peak pulse power (10/1000 µs), and operates from −55 °C to +150 °C - used in automotive sensor interface protection and industrial I/O line surge suppression.
For engineers reviewing the SMAJ18-E3/61 datasheet, SMAJ18-E3/61 pinout, SMAJ18-E3/61 application, or SMAJ18-E3/61 equivalent, this page delivers verified electrical parameters, JEDEC-compliant thermal resistance (RθJA = 120 °C/W), RoHS-compliant matte tin plating, MSL Level 1 moisture sensitivity, and exact unidirectional polarity marking per Vishay Document 88390 Rev. 29-Oct-08.
Technical Context
This unidirectional TVS diode uses a glass-passivated silicon junction optimized for fast response (<1 ps) and low incremental surge resistance. Its breakdown voltage (VBR) is specified at 20.0–24.4 V with 1 mA test current, ensuring reliable triggering above 18 V stand-off while maintaining <1 µA leakage at rated VWM.
Designed for surface-mount automated placement, it meets J-STD-020 MSL Level 1 and withstands solder reflow up to 260 °C for 40 s. The device supports repetitive surge duty cycles ≤0.01 % and derates linearly above 25 °C ambient per Fig. 2 in the datasheet.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - Maximum continuous reverse operating voltage before clamping begins; defines safe DC/AC working margin. |
| VC @ IPPM | 32.2 V at 12.4 A - Clamped voltage during 10/1000 µs surge; determines protected circuit's maximum transient exposure. |
| PPPM | 400 W - Peak pulse power handling capability; validates robustness against IEC 61000-4-5 Level 4 surges. |
| IFSM | 40 A - Single half-sine surge rating (8.3 ms); supports high-energy inductive kickback in relay/motor drive circuits. |
| TJ Range | −55 °C to +150 °C - Extended junction temperature range enables under-hood automotive and industrial control use. |
| RθJA | 120 °C/W - Thermal resistance from junction to ambient on 0.2 × 0.2″ copper pads; informs PCB thermal layout requirements. |
Pinout & Package
Package: DO-214AC (SMA), surface-mount, molded epoxy case meeting UL 94 V-0 flammability rating. Cathode indicated by band on one end; anode is unmarked terminal.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (banded end) | Transient current sink | Receives surge energy during reverse-biased clamping; connects to protected line. |
| Anode (unmarked end) | Reference node | Typically tied to ground or lower-potential rail; completes clamping path during overvoltage events. |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Ensures stable VBR and low leakage across temperature and lifetime; eliminates passivation-related drift. |
| MSL Level 1 compliance | Enables direct placement without baking; supports standard SMT reflow profiles including peak 260 °C. |
| RoHS-compliant matte tin plating | Guarantees solderability per J-STD-002 and whisker resistance per JESD201 Class 1A (E3 suffix). |
| Low incremental surge resistance | Minimizes VC overshoot during fast-rising transients (e.g., ESD >15 kV), improving protection margin. |
Applications
| Automotive Sensor Protection | Industrial PLC I/O Protection |
|---|---|
Use Scenario: Protecting CAN/LIN bus transceivers and analog sensor inputs (e.g., pressure, temperature) from load dump and ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Unidirectional clamping element placed between signal line and chassis ground. Use Value: Limits transient voltage to ≤32.2 V, preventing damage to 3.3 V/5 V interface ICs while surviving 40 A surge currents. |
Use Scenario: Safeguarding digital input modules from inductive kickback of solenoids, contactors, and motor starters. IC Role / Device Role / Timing Role: Standoff-rated TVS on 24 V DC input lines, triggered only during overvoltage events. Use Value: Withstands 400 W surges and maintains <1 µA leakage at 18 V, enabling low-power monitoring without false triggers. |
| Consumer Power Adapter Input | Telecom Line Interface |
Use Scenario: Secondary-side surge suppression in AC/DC adapters exposed to lightning-induced surges on DC output rails. IC Role / Device Role / Timing Role: Fast-clamping device parallel to DC output, shunting energy to ground during overvoltage. Use Value: Clamps within nanoseconds to 32.2 V, protecting downstream DC-DC converters and USB power delivery ICs. |
Use Scenario: Protecting Ethernet PHYs and RS-485 transceivers from induced surges on twisted-pair data lines. IC Role / Device Role / Timing Role: Unidirectional TVS on VCC-to-line or line-to-ground paths in isolated interfaces. Use Value: Delivers 400 W pulse handling with 120 °C/W thermal resistance, enabling compact board layouts without heatsinking. |
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 | Lower VBR (20.0–22.1 V vs. 20.0–24.4 V); tighter tolerance; 29.2 V clamping at 13.7 A. | Better suited for precision 18 V rail protection where tighter VBR distribution reduces false triggering risk. | Select SMAJ18A-E3/61 when clamping consistency across production lots is critical and 29.2 V VC is acceptable. |
| SMCJ18A-E3/57T | Higher power rating (1500 W vs. 400 W); same VWM/VC; larger DO-214AB (SMC) package. | Required for higher-energy threats (e.g., IEC 61000-4-5 Level 5) where 400 W is insufficient. | Choose SMCJ18A-E3/57T only if system-level testing confirms need for >400 W surge handling; requires PCB layout change. |
Compared with SMAJ18-E3/61, SMAJ18A-E3/61 offers improved VBR uniformity at identical footprint, while SMCJ18A-E3/57T trades package size for 3.75× higher pulse power - neither is pin-compatible, but both serve adjacent protection tiers in Vishay's TVS family.
Availability
SMAJ18-E3/61 is available at Aetrix Electronics and suitable for automotive sensor interfaces, industrial PLC I/O modules, and telecom line protection requiring stable component supply, full traceability, and long-term lifecycle support.
Supply support for SMAJ18-E3/61 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 and automotive qualification.
The SMAJ series is engineered for high-reliability transient suppression in harsh environments - targeting automotive, industrial, and telecom applications where robustness against ESD, lightning, and inductive switching is mandatory.
FAQ
What is the clamping voltage of SMAJ18-E3/61 under a 10/1000 µs surge?
The SMAJ18-E3/61 clamps to a maximum of 32.2 V when subjected to its rated peak pulse current of 12.4 A with a 10/1000 µs waveform. This value is measured per Figure 1 and Table 1 in Vishay Document 88390, and defines the upper voltage limit imposed on protected circuitry during standardized surge events. The SMAJ18-E3/61 maintains this clamping performance across its full operating temperature range.
Is SMAJ18-E3/61 unidirectional or bidirectional?
SMAJ18-E3/61 is a unidirectional transient voltage suppressor, indicated by the absence of "C" or "CA" suffix and confirmed by its single cathode band marking. It conducts only during reverse-bias overvoltage conditions and blocks forward current like a standard rectifier diode. The SMAJ18-E3/61 is not rated for bidirectional operation - for symmetrical protection, SMAJ18CA-E3/61 must be selected instead.
What does the "E3/61" suffix mean in SMAJ18-E3/61?
The "E3" suffix denotes RoHS-compliant, commercial-grade construction with matte tin-plated leads qualified to JESD201 Class 1A whisker resistance. The "/61" indicates packaging in 7-inch plastic tape-and-reel format with 1800 units per reel. This ordering code is explicitly listed in the "ORDERING INFORMATION" section of Vishay Document 88390 and ensures correct material compliance and logistics configuration for SMAJ18-E3/61.
Can SMAJ18-E3/61 replace SMAJ18A-E3/61 in existing designs?
No - SMAJ18-E3/61 and SMAJ18A-E3/61 are not interchangeable without validation. While both share the same VWM (18 V), SMAJ18A-E3/61 has a tighter VBR range (20.0–22.1 V) and lower clamping voltage (29.2 V vs. 32.2 V). Substituting SMAJ18-E3/61 may increase clamping stress on downstream ICs. The SMAJ18-E3/61 should only replace SMAJ18A-E3/61 after verifying system-level surge immunity with the higher VC.
What is the maximum junction temperature rating for SMAJ18-E3/61?
The SMAJ18-E3/61 has a maximum junction temperature (TJ) rating of +150 °C, as specified in the "MAXIMUM RATINGS" table of Vishay Document 88390. This allows operation in under-hood automotive environments and industrial enclosures with elevated ambient temperatures. Derating of peak pulse power begins above 25 °C ambient per Figure 2, and thermal design must ensure RθJA = 120 °C/W is achieved using the recommended 0.2 × 0.2 inch copper pads.
SMAJ18-E3/61 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:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ18-E3/61 FAQ
1.How can I place an order for SMAJ18-E3/61 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ18-E3/61 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 SMAJ18-E3/61 reliable?
The price and inventory of SMAJ18-E3/61 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ18-E3/61 is usually 5 days.
3.What payment methods are accepted for SMAJ18-E3/61?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ18-E3/61 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ18-E3/61?
SMAJ18-E3/61 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ18-E3/61 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 SMAJ18-E3/61?
For technical support, including SMAJ18-E3/61 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ18-E3/61 requirements.
6.How does Aetrix verify that SMAJ18-E3/61 is sourced from the original manufacturer or authorized distributors?
All SMAJ18-E3/61 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 SMAJ18-E3/61 meets industry standards.
7.What is the process for return or replacement of SMAJ18-E3/61?
All SMAJ18-E3/61 units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ18-E3/61, 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 SMAJ18-E3/61 part is unused and in its original packaging.
Return procedure for SMAJ18-E3/61:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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