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Vishay General Semiconductor - Diodes Division SMCJ18-E3/9AT
- Part No.:
- SMCJ18-E3/9AT
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SMCJ18-E3/9AT.pdf
- Description:
- TVS DIODE 18VWM 32.2VC DO214AB
- Quantity:
- Payment:
- Shipping:
Inventory:7,818
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Product details
Overview
SMCJ18-E3/9AT from Vishay General Semiconductor is a unidirectional transient voltage suppressor (TVS) diode in DO-214AB (SMCJ) package, designed for robust overvoltage protection of sensitive electronics. It features a 18 V standoff voltage (VWM), 20.0–22.1 V breakdown range (VBR at 1.0 mA), 29.2 V clamping voltage (VC) at 51.4 A peak pulse current, and 1500 W peak pulse power rating with 10/1000 µs waveform.
For engineers reviewing the SMCJ18-E3/9AT datasheet, SMCJ18-E3/9AT pinout, SMCJ18-E3/9AT application, or SMCJ18-E3/9AT equivalent, key selection criteria include clamping performance under automotive load-dump transients, thermal resistance (RθJA = 75 °C/W), AEC-Q101 qualification, RoHS compliance, and compatibility with automated SMT placement on 8.0 mm × 8.0 mm copper pads.
Technical Context
The SMCJ18-E3/9AT operates as a silicon avalanche diode, leveraging glass-passivated junction technology for stable, repeatable clamping behavior. Its unidirectional polarity-marked with a cathode band-enables integration into DC-biased signal or power lines where reverse conduction must be blocked.
It delivers fast response time (<1 ps) to transient events such as inductive switching spikes and ESD, with low incremental surge resistance ensuring minimal voltage overshoot during 1500 W surges. Thermal derating follows JESD22-A104 curves, maintaining safe operation up to TJ = 150 °C when mounted per recommended pad layout.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - Maximum continuous reverse operating voltage before clamping begins; sets upper limit for normal circuit operation. |
| VBR (min/max) | 20.0 V / 22.1 V at 1.0 mA - Confirmed breakdown threshold range; ensures reliable turn-on within defined tolerance under standardized test conditions. |
| VC @ IPPM | 29.2 V at 51.4 A - Clamped voltage during 1500 W transient; defines worst-case overvoltage seen by protected IC or MOSFET. |
| PPPM | 1500 W - Peak pulse power handling with 10/1000 µs waveform; validates suitability for ISO 7637-2 Pulse 5a/b automotive load-dump suppression. |
| TJ max | +150 °C - Maximum junction temperature; supports operation in under-hood automotive environments with proper PCB thermal design. |
| RθJA | 75 °C/W - Junction-to-ambient thermal resistance on standard 8.0 mm × 8.0 mm pads; enables thermal budget calculation for sustained surge duty cycles. |
Pinout & Package
Package: DO-214AB (SMCJ), surface-mount, low-profile case with matte tin-plated leads solderable per J-STD-002 and JESD22-B102. Cathode identified by molded band.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential side of protected line (e.g., ground or return path); conducts during forward surge only in uni-directional configuration. |
| Cathode (banded end) | Reverse-blocking & clamping terminal | Connected to higher-potential side (e.g., supply rail or signal line); avalanches into conduction when reverse voltage exceeds VBR, shunting surge current to ground. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, humidity bias, and mechanical shock per JESD47. |
| Glass-passivated junction | Ensures stable VBR tolerance and long-term parameter stability across life cycle and environmental stress. |
| MSL Level 1 (260 °C peak) | Compatible with standard lead-free reflow profiles without moisture sensitivity concerns or baking requirements. |
| Low incremental surge resistance | Minimizes dynamic impedance during transient clamping, reducing overshoot and improving protection margin for downstream components. |
Applications
| Automotive Power Rail Protection | Industrial Sensor Signal Line Protection |
|---|---|
Use Scenario: Protecting 12 V battery-fed ECUs against ISO 7637-2 Pulse 5a (load dump) transients up to 60 V/100 ms. IC Role / Device Role: Primary clamping element placed between battery input and upstream DC-DC converter input. Use Value: Limits voltage seen by converter IC to ≤29.2 V during 1500 W surge, preventing latch-up or permanent damage while meeting AEC-Q101 requirements. | Use Scenario: Safeguarding analog outputs of pressure or temperature sensors connected to PLC I/O modules exposed to field wiring transients. IC Role / Device Role: Unidirectional TVS placed across sensor output and ground to clamp induced surges from relay switching or lightning coupling. Use Value: Maintains signal integrity below 29.2 V clamping level, preserving ADC accuracy and avoiding false readings during 10/1000 µs transients. |
| Consumer Device USB Port Protection | Telecom Base Station DC Feed Protection |
Use Scenario: Adding secondary overvoltage protection on VBUS line of USB 2.0 host ports subjected to hot-plug and ESD events. IC Role / Device Role: Standoff-rated TVS (18 V) placed after primary ESD array to handle higher-energy surges beyond ±15 kV contact discharge. Use Value: Provides 1500 W surge capacity with 29.2 V clamping-well below USB 2.0 VBUS absolute maximum rating of 6.8 V-when used in conjunction with series impedance. | Use Scenario: Protecting -48 V DC feed inputs of remote radio units from induced surges due to nearby lightning strikes on tower cabling. IC Role / Device Role: Reverse-polarity configured SMCJ18-E3/9AT (cathode to -48 V rail) clamps positive-going transients toward ground. Use Value: Withstands 1500 W pulses and maintains clamping at 29.2 V, enabling robust front-end protection without derating for negative-rail applications. |
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-E3/61T | Lower PPPM (400 W), smaller SMA package (DO-214AC), higher RθJA (110 °C/W), same VWM/VC specs. | Not suitable for automotive load-dump; limited to lower-energy transients like ESD or relay bounce. | Select when board space is constrained and surge energy is ≤400 W; verify thermal margin with reduced pad area. |
| SMCJ18AHE3/9AT | Identical electrical specs but AEC-Q101 qualified (HE3 suffix), same DO-214AB package and marking code BET. | No functional difference; intended for automotive OEMs requiring formal qualification documentation and traceability. | Choose for Tier-1 automotive programs requiring full AEC-Q101 certification evidence and extended reliability testing records. |
Compared with SMCJ18-E3/9AT, SMAJ18A-E3/61T offers footprint savings at the cost of 73 % lower surge power handling, while SMCJ18AHE3/9AT provides identical protection performance with certified automotive qualification-making it the preferred choice where formal AEC-Q101 compliance is contractually mandated.
Availability
SMCJ18-E3/9AT is available at Aetrix Electronics and suitable for automotive electronic control units, industrial sensor interfaces, consumer USB power delivery circuits, and telecom DC feed protection requiring stable component supply and consistent surge performance.
Supply support for SMCJ18-E3/9AT 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, rectifiers, TVS devices, and optoelectronics with emphasis on high-reliability, automotive-qualified, and industry-standard solutions.
The SMCJ series belongs to Vishay's TRANSZORB® family of transient voltage suppressors, engineered specifically for high-power, fast-response overvoltage protection in harsh environments including automotive, industrial, and telecom infrastructure.
FAQ
What is the clamping voltage of the SMCJ18-E3/9AT and how is it measured?
The SMCJ18-E3/9AT has a maximum clamping voltage (VC) of 29.2 V, measured at its peak pulse current (IPPM) of 51.4 A using a 10/1000 µs double-exponential transient waveform. This value is guaranteed per Vishay's datasheet Document Number 88394 and reflects the worst-case voltage imposed on protected circuitry during a 1500 W surge event. The SMCJ18-E3/9AT maintains this clamping performance across its rated junction temperature range.
Is the SMCJ18-E3/9AT suitable for automotive applications?
Yes, the SMCJ18-E3/9AT is AEC-Q101 qualified and explicitly rated for automotive use per Vishay's documentation. It meets requirements for temperature cycling, mechanical shock, and humidity bias, and is designed to suppress load-dump transients (ISO 7637-2 Pulse 5a/b) in 12 V systems. Its DO-214AB package, MSL Level 1 rating, and 150 °C TJ max make the SMCJ18-E3/9AT appropriate for under-hood and body-control module deployments.
How does the SMCJ18-E3/9AT differ from bi-directional variants like SMCJ18CA?
The SMCJ18-E3/9AT is unidirectional, featuring a cathode band and blocking reverse current until breakdown occurs-ideal for DC-biased lines. In contrast, SMCJ18CA is bi-directional with no polarity marking and symmetrical clamping in both directions, suited for AC or floating signal lines. Their VWM (18 V), VBR, and VC values differ slightly due to test methodology; the SMCJ18-E3/9AT is not interchangeable with SMCJ18CA without circuit review.
What is the thermal resistance of the SMCJ18-E3/9AT and how does it affect layout?
The SMCJ18-E3/9AT has a typical junction-to-ambient thermal resistance (RθJA) of 75 °C/W when mounted on 0.31" × 0.31" (8.0 mm × 8.0 mm) copper pads per terminal. This value assumes minimum recommended pad layout per Vishay's datasheet; reducing pad size increases RθJA, risking thermal runaway during repetitive surges. For reliable operation, maintain full copper exposure and avoid thermal vias that compromise pad area unless validated per JEDEC standards.
Does the SMCJ18-E3/9AT require external series impedance for effective protection?
The SMCJ18-E3/9AT functions as a shunt protector and does not require series impedance to clamp transients-but adding a current-limiting resistor or ferrite bead upstream improves system-level robustness by limiting total surge current and reducing stress on the diode. For example, in USB VBUS protection, a 5 Ω resistor combined with the SMCJ18-E3/9AT lowers peak current into the TVS, extending lifetime and lowering clamped voltage. Layout and system impedance must be co-optimized for the target threat profile.
SMCJ18-E3/9AT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AB, SMC
- 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):
- 46.6A
- Power - Peak Pulse:
- 1500W (1.5kW)
- 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-214AB (SMCJ)
SMCJ18-E3/9AT FAQ
1.How can I place an order for SMCJ18-E3/9AT through Aetrix?
Please submit a Request for Quotation (RFQ) for SMCJ18-E3/9AT 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 SMCJ18-E3/9AT reliable?
The price and inventory of SMCJ18-E3/9AT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMCJ18-E3/9AT is usually 5 days.
3.What payment methods are accepted for SMCJ18-E3/9AT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMCJ18-E3/9AT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMCJ18-E3/9AT?
SMCJ18-E3/9AT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMCJ18-E3/9AT 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 SMCJ18-E3/9AT?
For technical support, including SMCJ18-E3/9AT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMCJ18-E3/9AT requirements.
6.How does Aetrix verify that SMCJ18-E3/9AT is sourced from the original manufacturer or authorized distributors?
All SMCJ18-E3/9AT 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 SMCJ18-E3/9AT meets industry standards.
7.What is the process for return or replacement of SMCJ18-E3/9AT?
All SMCJ18-E3/9AT units undergo pre-shipment inspection (PSI). If there is an issue with SMCJ18-E3/9AT, 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 SMCJ18-E3/9AT part is unused and in its original packaging.
Return procedure for SMCJ18-E3/9AT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMCJ18-E3/9AT Tags
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