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Vishay General Semiconductor - Diodes Division SMCJ18A-M3/9AT
- Part No.:
- SMCJ18A-M3/9AT
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SMCJ18A-M3/9AT.pdf
- Description:
- TVS DIODE 18VWM 29.2VC DO214AB
- Quantity:
- Payment:
- Shipping:
Inventory:8,269
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Product details
Overview
SMCJ18A-M3/9AT from Vishay General Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in SMC (DO-214AB) package, with 18 V stand-off voltage (VWM), 20.0–22.1 V breakdown voltage (VBR) at 1 mA, 29.2 V clamping voltage (VC) at 51.4 A peak pulse current (IPPM), and 1500 W peak pulse power (PPPM) rating for 10/1000 µs transients. It protects MOSFETs, ICs, and sensor signal lines against inductive switching surges and ESD in automotive and industrial power rails.
For engineers reviewing the SMCJ18A-M3/9AT datasheet, SMCJ18A-M3/9AT pinout, SMCJ18A-M3/9AT application, or SMCJ18A-M3/9AT equivalent, this device is selected for robust overvoltage protection where low clamping ratio, fast response (<1 ns), and AEC-Q101 qualification readiness (via HM3 suffix variants) are critical - especially in 24 V DC systems with high surge immunity requirements.
Technical Context
The SMCJ18A-M3/9AT uses a glass-passivated silicon junction optimized for low incremental surge resistance and stable clamping under repetitive 10/1000 µs transients. Its unidirectional polarity features a cathode band marking and exhibits 1.0 µA maximum reverse leakage at 18 V, enabling low-power standby compatibility.
Thermally, it delivers 75 °C/W junction-to-ambient thermal resistance on standard 8.0 mm × 8.0 mm copper pads and supports continuous operation up to +150 °C junction temperature, with derating above 25 °C ambient per Figure 2 of the datasheet.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - Maximum continuous reverse operating voltage before clamping begins; defines safe DC bias margin for 24 V rail protection. |
| VBR (min/max) | 20.0 V / 22.1 V at 1 mA - Confirmed breakdown range ensures reliable turn-on without premature conduction during normal operation. |
| VC @ IPPM | 29.2 V at 51.4 A - Clamping voltage limits downstream voltage stress during 1500 W transient events, yielding 1.62× VWM clamping ratio. |
| PPPM | 1500 W - Peak pulse power handling for standardized 10/1000 µs waveform; enables IEC 61000-4-5 Level 4 compliance when properly laid out. |
| TJ max. | +150 °C - Maximum junction temperature rating supports under-hood automotive and industrial environments without thermal shutdown. |
| Package | SMC (DO-214AB) - Surface-mount package with 7.75 mm × 6.22 mm footprint, compatible with automated placement and reflow soldering per J-STD-020 MSL level 1. |
Pinout & Package
SMCJ18A-M3/9AT is housed in an SMC (DO-214AB) package with two terminals: anode and cathode. The cathode is marked by a visible band on the body. No internal pins - leads are formed as molded-in terminals suitable for PCB soldering.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (banded end) | Transient current sink | Connected to protected line; conducts surge current to ground during overvoltage, requiring low-inductance grounding path. |
| Anode | Reference/ground return | Typically tied to system ground plane; must maintain minimal trace inductance to preserve clamping speed and effectiveness. |
Key Features
| Feature | Design Value |
|---|---|
| Low incremental surge resistance | Enables tighter clamping voltage control across varying surge currents, reducing voltage overshoot on sensitive loads. |
| Very fast response time (<1 ns) | Clamps transients before they propagate through circuitry, protecting high-speed logic and analog front-ends. |
| Halogen-free, RoHS-compliant (M3 suffix) | Meets environmental compliance requirements for industrial and automotive supply chains without compromising surge performance. |
| MSL level 1 moisture sensitivity | Allows unlimited floor life before reflow, eliminating bake-out steps and supporting just-in-time manufacturing flow. |
Applications
| Automotive Power Distribution | Industrial PLC I/O Protection |
|---|---|
Use Scenario: Protecting 24 V supply inputs in body control modules against load dump and alternator ripple. IC Role / Device Role / Timing Role: Unidirectional TVS placed between power rail and ground to clamp positive-going transients only. Use Value: Limits voltage excursion to ≤29.2 V during 1500 W surges, preventing damage to downstream DC-DC converters and microcontrollers. | Use Scenario: Shielding digital input channels of programmable logic controllers from field-wiring induced surges. IC Role / Device Role / Timing Role: Standoff-rated TVS on each isolated input channel, absorbing ±1 kV EFT bursts per IEC 61000-4-4. Use Value: Maintains signal integrity with <1.0 µA leakage at 18 V, avoiding false triggering while surviving repeated 51.4 A pulses. |
| Motor Drive Gate Protection | Telecom DC Power Interface |
Use Scenario: Safeguarding high-side MOSFET gate drivers in brushed DC motor controllers from inductive kickback. IC Role / Device Role / Timing Role: TVS connected between gate and source to clamp negative-going spikes during switch-off. Use Value: Fast sub-ns response prevents gate oxide breakdown; 29.2 V VC ensures driver IC remains within absolute maximum ratings. | Use Scenario: Front-end protection for 48 V telecom power feeds exposed to lightning-induced surges on outdoor plant equipment. IC Role / Device Role / Timing Role: Primary unidirectional clamping device upstream of DC-DC stage, rated for 10/1000 µs threat waveforms. Use Value: 1500 W PPPM capacity meets GR-1089-CORE Level 3 requirements when paired with appropriate series impedance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ18A-E3/61T | Lower PPPM (400 W), SMA package (smaller footprint, higher RθJA = 110 °C/W), same VWM/VBR/VC specs. | Restricted to lower-energy transients; unsuitable for IEC 61000-4-5 Level 4 or automotive load dump. | Select only for space-constrained consumer-grade designs with <500 W surge exposure. |
| SMCJ18CA-M3/9AT | Bidirectional variant with identical VWM (18 V), VBR (20.0–22.1 V), VC (29.2 V), and PPPM (1500 W); no polarity marking. | Required for AC-coupled or dual-polarity signal lines (e.g., RS-485, CAN bus) where symmetric clamping is mandatory. | Choose when protecting bidirectional data lines or floating references - not a drop-in replacement due to polarity and marking differences. |
Compared with SMAJ18A-E3/61T and SMCJ18CA-M3/9AT, the SMCJ18A-M3/9AT uniquely balances high-energy 1500 W clamping, unidirectional polarity for DC rail use, and SMC package thermal performance - making it optimal for automotive and industrial 24 V power protection where both energy handling and thermal reliability are non-negotiable.
Availability
SMCJ18A-M3/9AT is available at Aetrix Electronics and suitable for automotive power distribution, industrial PLC I/O protection, motor drive gate circuits, and telecom DC power interfaces requiring stable component supply, halogen-free compliance, and long-term lifecycle continuity.
Supply support for SMCJ18A-M3/9AT 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 reliability, ruggedness, and application-specific qualification.
The SMCJ series was engineered for high-energy transient suppression in harsh environments - targeting automotive, industrial, and telecom infrastructure where failure modes must be mitigated via proven clamping performance and AEC-Q101-ready construction.
FAQ
What is the clamping voltage of the SMCJ18A-M3/9AT under maximum rated surge current?
The SMCJ18A-M3/9AT has a maximum clamping voltage (VC) of 29.2 V when subjected to its rated peak pulse current (IPPM) of 51.4 A using the 10/1000 µs waveform. This value is measured per ANSI/IEEE C62.35 standards and confirmed in the Vishay datasheet revision 09-Jan-2024. The SMCJ18A-M3/9AT maintains this clamping performance across its full operating temperature range, ensuring predictable protection behavior in real-world conditions.
Is the SMCJ18A-M3/9AT suitable for automotive applications?
The SMCJ18A-M3/9AT itself is commercial-grade (M3 suffix), but Vishay offers AEC-Q101 qualified versions under HM3 suffixes (e.g., SMCJ18A-HM3/9AT). While the SMCJ18A-M3/9AT shares identical electrical characteristics and SMC package construction, formal automotive qualification requires the HM3 variant. Engineers deploying the SMCJ18A-M3/9AT in automotive prototypes should verify qualification status with Vishay documentation before final design release.
How does the SMCJ18A-M3/9AT differ from the bidirectional SMCJ18CA-M3/9AT?
The SMCJ18A-M3/9AT is unidirectional with a cathode band marking and blocks reverse current until breakdown, whereas the SMCJ18CA-M3/9AT is bidirectional with no polarity marking and clamps in both directions. Both share identical VWM (18 V), VBR (20.0–22.1 V), VC (29.2 V), and PPPM (1500 W), but the SMCJ18A-M3/9AT is intended for DC power rail protection, while the CA version serves AC or differential signal lines like RS-485. They are not interchangeable without circuit review.
What is the thermal resistance of the SMCJ18A-M3/9AT, and how does it affect layout?
The SMCJ18A-M3/9AT has a typical junction-to-ambient thermal resistance (RθJA) of 75 °C/W when mounted on 8.0 mm × 8.0 mm copper pads per terminal. This value assumes minimum recommended pad layout per Vishay's DO-214AB outline. To avoid thermal runaway during repetitive surges, PCB layout must provide adequate copper area and minimize trace length to ground - undersized pads increase RθJA and reduce safe surge repetition rate. The SMCJ18A-M3/9AT's RθJL of 15 °C/W further emphasizes the need for short, wide thermal paths to internal ground planes.
Does the SMCJ18A-M3/9AT meet any industry surge immunity standards?
The SMCJ18A-M3/9AT is designed to support compliance with IEC 61000-4-5 (surge immunity) and IEC 61000-4-4 (EFT) when implemented with proper board-level design - including series impedance, grounding strategy, and layout per Vishay Application Note AN8001. Its 1500 W PPPM rating aligns with Level 4 (4 kV line-earth, 2 kV line-line) testing requirements for industrial equipment. However, system-level certification depends on full implementation; the SMCJ18A-M3/9AT alone does not constitute full compliance.
SMCJ18A-M3/9AT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AB, SMC
- Series:
- TransZorb®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- 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):
- 51.4A
- 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 (SMC)
SMCJ18A-M3/9AT FAQ
1.How can I place an order for SMCJ18A-M3/9AT through Aetrix?
Please submit a Request for Quotation (RFQ) for SMCJ18A-M3/9AT 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 SMCJ18A-M3/9AT reliable?
The price and inventory of SMCJ18A-M3/9AT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMCJ18A-M3/9AT is usually 5 days.
3.What payment methods are accepted for SMCJ18A-M3/9AT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMCJ18A-M3/9AT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMCJ18A-M3/9AT?
SMCJ18A-M3/9AT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMCJ18A-M3/9AT 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 SMCJ18A-M3/9AT?
For technical support, including SMCJ18A-M3/9AT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMCJ18A-M3/9AT requirements.
6.How does Aetrix verify that SMCJ18A-M3/9AT is sourced from the original manufacturer or authorized distributors?
All SMCJ18A-M3/9AT 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 SMCJ18A-M3/9AT meets industry standards.
7.What is the process for return or replacement of SMCJ18A-M3/9AT?
All SMCJ18A-M3/9AT units undergo pre-shipment inspection (PSI). If there is an issue with SMCJ18A-M3/9AT, 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 SMCJ18A-M3/9AT part is unused and in its original packaging.
Return procedure for SMCJ18A-M3/9AT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMCJ18A-M3/9AT Tags
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