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Vishay General Semiconductor - Diodes Division SMCJ18A-E3/9AT
- Part No.:
- SMCJ18A-E3/9AT
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SMCJ18A-E3/9AT.pdf
- Description:
- TVS DIODE 18VWM 29.2VC DO214AB
- Quantity:
- Payment:
- Shipping:
Inventory:10,235
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Product details
Overview
SMCJ18A-E3/9AT from Vishay General Semiconductor is a unidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMC (DO-214AB) package, designed for robust overvoltage protection of DC power rails and signal lines. It features a 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) with 10/1000 μs waveform - deployed in automotive power supply inputs and industrial sensor interfaces.
For engineers reviewing the SMCJ18A-E3/9AT datasheet, SMCJ18A-E3/9AT pinout, SMCJ18A-E3/9AT application, or SMCJ18A-E3/9AT equivalent, this page delivers verified electrical parameters, thermal derating behavior, junction-to-ambient thermal resistance (75 °C/W), AEC-Q101 qualification status, and RoHS-compliant commercial-grade construction - all critical for ESD/surge hardening in high-reliability embedded systems.
Technical Context
The SMCJ18A-E3/9AT operates as a unidirectional avalanche-clamping device, triggered when reverse voltage exceeds its 20.0–22.1 V breakdown range. Its glass-passivated junction ensures stable VBR tolerance and low leakage (<1.0 μA at 18 V), while low incremental surge resistance enables rapid energy diversion during transients.
Thermally, it sustains 150 °C maximum junction temperature with 75 °C/W junction-to-ambient resistance on standard 8.0 mm × 8.0 mm copper pads, and supports 200 A non-repetitive forward surge current (IFSM) per 8.3 ms half-sine wave - confirming suitability for automotive load-dump and inductive-switching event suppression.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - Maximum continuous reverse operating voltage before clamping begins; defines safe DC rail margin for 24 V nominal systems. |
| VBR (min/max) | 20.0 V / 22.1 V at 1 mA - Confirmed breakdown threshold range; ensures predictable turn-on under transient overvoltage conditions. |
| VC @ IPPM | 29.2 V at 51.4 A - Clamped voltage during 10/1000 μs surge; limits downstream IC stress to sub-30 V during 1500 W events. |
| PPPM | 1500 W - Peak pulse power handling capability; meets ISO 7637-2 Pulse 1/2/5a requirements for automotive electronics. |
| TJ max. | +150 °C - Maximum junction temperature rating; supports operation in engine-bay or industrial control cabinet environments. |
| RθJA | 75 °C/W - Thermal resistance junction-to-ambient on recommended pad layout; informs heatsinking needs for sustained surge duty cycles. |
| ID @ VWM | <1.0 μA - Reverse leakage at stand-off voltage; minimizes quiescent power loss in battery-powered sensor nodes. |
Pinout & Package
Package: SMC (DO-214AB), surface-mount, matte tin-plated leads, RoHS-compliant, MSL Level 1 (260 °C reflow peak). Cathode indicated by band marking; anode is unmarked end.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (banded end) | Transient current sink node | Connected to protected line; conducts surge current to ground when Vreverse > VBR. |
| Anode (unbanded end) | Reference/ground return path | Typically tied to system ground or low-impedance return plane; completes clamping loop during overvoltage events. |
Key Features
| Feature | Design Value |
|---|---|
| 1500 W peak pulse power (10/1000 μs) | Enables single-device protection against severe ISO 7637-2 load-dump transients in 24 V automotive systems without external series impedance. |
| 29.2 V clamping voltage at 51.4 A | Keeps protected 3.3 V/5 V logic rails and MCU I/O within safe absolute maximum ratings during surge events. |
| Glass-passivated junction | Ensures long-term VBR stability and low parameter drift across temperature (-55 °C to +150 °C) and lifetime cycling. |
| AEC-Q101 qualified option available | HE3/HM3 variants meet automotive reliability standards; SMCJ18A-E3/9AT is commercial-grade but shares identical die and package construction. |
| Low 75 °C/W RθJA on standard pads | Permits direct PCB-level thermal management without dedicated heatsinks in space-constrained industrial modules. |
Applications
| Automotive Power Input Protection | Industrial Sensor Signal Line Guarding |
|---|---|
|
Use Scenario: Protecting 24 V power input of body control module (BCM) against ISO 7637-2 Pulse 5a load-dump transients up to 60 V/100 ms. IC Role / Device Role / Timing Role: Unidirectional TVS clamp placed between input rail and chassis ground, activated within <1 ns of overvoltage onset. Use Value: Limits rail voltage to ≤29.2 V during 1500 W surges, preventing damage to upstream DC/DC converters and downstream microcontrollers. |
Use Scenario: Shielding analog output (4–20 mA) and CAN bus lines of pressure sensors in factory automation PLC I/O modules. IC Role / Device Role / Timing Role: Standby-mode transient suppressor on signal lines, absorbing ESD (IEC 61000-4-2 ±8 kV contact) and fast switching noise. Use Value: Maintains signal integrity with <1.0 μA leakage at 18 V, while clamping ESD-induced spikes to sub-30 V before they reach precision ADC front-ends. |
| Consumer Appliance Motor Drive Protection | Telecom Power Supply Surge Hardening |
|
Use Scenario: Safeguarding H-bridge gate drivers in smart HVAC blower units subjected to inductive kickback from brushed DC motors. IC Role / Device Role / Timing Role: Rail-to-ground TVS on motor supply rail, conducting flyback energy away from MOSFET source/drain terminals. Use Value: Withstands 200 A 8.3 ms surge (IFSM), eliminating need for redundant clamping or oversized FETs in cost-sensitive white-goods designs. |
Use Scenario: Front-end overvoltage protection for 48 V PoE-powered telecom access points exposed to lightning-induced surges on outdoor Ethernet runs. IC Role / Device Role / Timing Role: Primary clamping element on DC input, coordinated with MOV and gas discharge tube in multi-stage protection network. Use Value: Provides precise 18 V stand-off and sharp 29.2 V clamping to prevent premature triggering of downstream crowbar circuits while absorbing 1500 W 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 |
|---|---|---|---|
| SMBJ18A-E3/52T | Lower PPPM (600 W), smaller SMB (DO-214AA) package, same VWM/VBR/VC specs. | Reduced surge capacity suits consumer-grade 12 V systems; not rated for automotive load-dump. | Select when board space is constrained and peak surge energy is ≤600 W - verify thermal margin with RθJA = 110 °C/W. |
| SMCJ18CA-E3/9AT | Bidirectional variant; identical VWM (18 V), VBR (20.0–22.1 V), VC (29.2 V), and PPPM (1500 W). | Required for AC-coupled or differential signal lines (e.g., RS-485, CAN FD) where polarity reversal occurs. | Choose only if bidirectional clamping is needed; unidirectional SMCJ18A-E3/9AT offers lower leakage and avoids unnecessary complexity in DC rail protection. |
Compared with SMBJ18A-E3/52T, SMCJ18A-E3/9AT delivers 2.5× higher surge power handling and superior thermal performance; versus SMCJ18CA-E3/9AT, it provides tighter leakage control and simpler grounding in unidirectional DC applications - making it optimal for automotive and industrial 24 V rail protection.
Availability
SMCJ18A-E3/9AT is available at Aetrix Electronics and suitable for automotive electronic control units, industrial sensor interface modules, and telecom power supply designs requiring stable component supply, full traceability, and long-term lifecycle support.
Supply support for SMCJ18A-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, MOSFETs, and protection devices with emphasis on reliability, efficiency, and application-specific optimization.
The SMCJ series is engineered for high-energy transient suppression in harsh environments - targeting automotive, industrial, and telecom systems where robustness against load dump, ESD, and inductive switching is mission-critical.
FAQ
What is the clamping voltage of the SMCJ18A-E3/9AT under a 10/1000 μs surge?
The SMCJ18A-E3/9AT clamps to 29.2 V at its rated peak pulse current of 51.4 A under a 10/1000 μs waveform. This value is measured per ANSI/IEEE C62.35 and confirmed in Vishay's datasheet revision 09-Jan-2024. The clamping voltage directly determines the maximum stress imposed on downstream components during surge events, making it a key parameter for validating protection margins in 24 V systems using the SMCJ18A-E3/9AT.
Is the SMCJ18A-E3/9AT AEC-Q101 qualified?
No, the SMCJ18A-E3/9AT is RoHS-compliant commercial-grade with base P/N-E3 suffix. AEC-Q101 qualification applies only to variants with HE3 or HM3 suffixes (e.g., SMCJ18AHE3_A/I). While the SMCJ18A-E3/9AT shares identical die, package, and electrical characteristics with qualified versions, it lacks the extended reliability testing required for automotive under-hood applications - confirm qualification status via ordering code before deployment in AEC-Q101–mandated designs.
What is the maximum operating temperature for the SMCJ18A-E3/9AT?
The SMCJ18A-E3/9AT has a maximum junction temperature (TJ max.) of +150 °C and an operating junction/storage temperature range of -55 °C to +150 °C. This rating is validated per JEDEC standards and supports use in engine compartments, industrial enclosures, and telecom base stations. Derating curves in the datasheet show that at 100 °C ambient, the device maintains full 1500 W surge capability only with adequate PCB copper area - always reference Fig. 2 for thermal design with the SMCJ18A-E3/9AT.
How does the SMCJ18A-E3/9AT differ from the SMCJ18CA-E3/9AT?
The SMCJ18A-E3/9AT is unidirectional, with cathode marked and optimized for DC rail protection; the SMCJ18CA-E3/9AT is bidirectional, unmarked, and suited for AC or differential lines like RS-485. Both share identical VWM (18 V), VBR (20.0–22.1 V), VC (29.2 V), and PPPM (1500 W), but the unidirectional SMCJ18A-E3/9AT exhibits lower reverse leakage (<1.0 μA vs. ≤2.0 μA for CA version), making it preferable for low-power standby circuits where leakage current impacts battery life.
What is the thermal resistance junction-to-ambient for the SMCJ18A-E3/9AT?
The SMCJ18A-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 - as specified in Vishay document 88394. This value assumes standard FR-4 PCB with no internal copper planes; adding inner-layer thermal vias or larger copper pours reduces effective RθJA. Accurate thermal modeling using this RθJA is essential to avoid junction overheating during repetitive surge events involving the SMCJ18A-E3/9AT.
SMCJ18A-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:
- 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 (SMCJ)
SMCJ18A-E3/9AT FAQ
1.How can I place an order for SMCJ18A-E3/9AT through Aetrix?
Please submit a Request for Quotation (RFQ) for SMCJ18A-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 SMCJ18A-E3/9AT reliable?
The price and inventory of SMCJ18A-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 SMCJ18A-E3/9AT is usually 5 days.
3.What payment methods are accepted for SMCJ18A-E3/9AT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMCJ18A-E3/9AT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMCJ18A-E3/9AT?
SMCJ18A-E3/9AT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMCJ18A-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 SMCJ18A-E3/9AT?
For technical support, including SMCJ18A-E3/9AT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMCJ18A-E3/9AT requirements.
6.How does Aetrix verify that SMCJ18A-E3/9AT is sourced from the original manufacturer or authorized distributors?
All SMCJ18A-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 SMCJ18A-E3/9AT meets industry standards.
7.What is the process for return or replacement of SMCJ18A-E3/9AT?
All SMCJ18A-E3/9AT units undergo pre-shipment inspection (PSI). If there is an issue with SMCJ18A-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 SMCJ18A-E3/9AT part is unused and in its original packaging.
Return procedure for SMCJ18A-E3/9AT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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