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Vishay General Semiconductor - Diodes Division SMBJ18A-E3/5B
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- Part No.:
- SMBJ18A-E3/5B
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ18A-E3/5B.pdf
- Description:
- TVS DIODE 18VWM 29.2VC DO214AA
- Quantity:
- Payment:
- Shipping:
Inventory:937
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Product details
Overview
SMBJ18A-E3/5B from Vishay General Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in SMB (DO-214AA) package, designed for clamping inductive switching transients and lightning-induced surges on power rails and signal lines. It features 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 20.5 A peak pulse current (IPPM), and 600 W peak pulse power (10/1000 µs waveform).
For engineers reviewing the SMBJ18A-E3/5B datasheet, SMBJ18A-E3/5B pinout, SMBJ18A-E3/5B application, or SMBJ18A-E3/5B equivalent, this page provides verified electrical parameters, thermal behavior, clamping performance under surge conditions, polarity marking convention, and RoHS-compliant commercial-grade sourcing context.
Technical Context
This unidirectional TVS diode operates as a voltage-clamping protection device across DC power inputs or low-voltage signal paths. Its glass-passivated junction ensures stable reverse leakage (<1.0 µA at 18 V) and fast response time (<1.0 ns), enabling effective suppression of ESD and fast-rising transients before downstream ICs or MOSFETs are damaged.
The SMBJ18A-E3/5B is rated for 150 °C maximum junction temperature and exhibits 0.092 %/°C temperature coefficient of VBR. Its thermal resistance is 100 °C/W (junction-to-ambient) on standard 0.2" × 0.2" copper pads, supporting reliable operation in industrial and automotive-adjacent environments without active cooling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - Maximum continuous reverse operating voltage before significant leakage begins; defines safe DC rail margin for 12–15 V systems. |
| VBR min/max | 20.0 V / 22.1 V at 1 mA - Confirmed breakdown range ensures predictable turn-on during overvoltage events without premature conduction. |
| VC @ IPPM | 29.2 V at 20.5 A - Clamping voltage under 10/1000 µs surge defines worst-case stress seen by protected circuitry. |
| PPPM | 600 W - Peak pulse power handling capacity determines survivability against IEC 61000-4-5 Level 3/4 surges. |
| ID @ VWM | ≤1.0 µA - Ultra-low reverse leakage preserves efficiency and avoids false triggering in high-impedance sensor interfaces. |
| TJ max | +150 °C - Enables deployment in under-hood automotive modules or enclosed industrial enclosures without derating. |
| RθJA | 100 °C/W - Thermal resistance measured on 0.2" × 0.2" copper pads; informs PCB layout requirements for sustained surge duty cycles. |
Pinout & Package
Package: SMB (DO-214AA), surface-mount, matte tin-plated leads, MSL Level 1 (260 °C reflow peak), RoHS-compliant (E3 suffix). Polarity marked with cathode band; anode and cathode terminals are axially oriented along the body.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (banded end) | High-side connection to protected line | Reverse-biased during normal operation; conducts when line voltage exceeds VBR to shunt surge current to ground. |
| Anode (non-banded end) | Low-side connection to reference (GND or return) | Provides low-impedance path for surge current; must be routed with minimal inductance to maintain clamping effectiveness. |
Key Features
| Feature | Design Value |
|---|---|
| 600 W peak pulse power (10/1000 µs) | Supports IEC 61000-4-5 4 kV surge immunity testing without degradation when properly mounted. |
| Glass passivated chip junction | Ensures long-term stability of VBR and leakage under thermal cycling and humidity exposure. |
| Low profile SMB package | Enables automated placement in space-constrained consumer and telecom PCBs while maintaining 600 W capability. |
| MSL Level 1 rating | Allows single-reflow assembly without baking; compatible with standard SMT production lines. |
| RoHS-compliant, commercial grade (E3) | Meets global environmental compliance requirements without halogen-free cost premium; suitable for non-automotive volume production. |
Applications
| Industrial Motor Drive Inputs | Automotive Body Control Module (BCM) Power Rails |
|---|---|
Use Scenario: Protection of 24 V DC input stage against load dump and inductive kickback from relay coils and solenoids. IC Role / Device Role / Timing Role: Unidirectional clamping TVS placed between VIN and GND, upstream of DC/DC converter input. Use Value: Limits transient voltage to ≤29.2 V, preventing damage to 36 V-rated input capacitors and controller ICs during 100 V/50 ms load dump events. |
Use Scenario: Surge suppression on 12 V battery-fed power bus feeding microcontrollers, CAN transceivers, and LED drivers. IC Role / Device Role / Timing Role: Standoff-rated TVS absorbing ISO 7637-2 Pulse 1 (−150 V) and Pulse 3a/b (±100 V) transients. Use Value: Maintains <1.0 µA leakage at 12 V nominal, avoiding battery drain while clamping to 29.2 V within nanoseconds. |
| Telecom PoE PD Interface | Consumer Appliance AC-DC Adapter Output |
Use Scenario: Secondary-side overvoltage protection on Powered Device (PD) interface after IEEE 802.3af/at isolation transformer. IC Role / Device Role / Timing Role: Unidirectional TVS connected across isolated 48–57 V DC output to protect PD controller and Ethernet PHY. Use Value: Withstands repetitive 10/1000 µs surges up to 600 W at 0.01% duty cycle, ensuring reliability in multi-port PoE switches. |
Use Scenario: Output rail protection in 5–19 V wall adapters for laptops, monitors, and smart home hubs. IC Role / Device Role / Timing Role: Final-stage TVS on regulated DC output to absorb capacitor discharge transients and ESD coupling from USB/USB-C ports. Use Value: 29.2 V clamping prevents latch-up in downstream USB PD controllers rated for ≤20 V absolute maximum. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ18CA-E3/5B | Bidirectional variant; symmetric VBR (20.0–22.1 V) in both polarities; same VC (29.2 V) and PPPM (600 W). | Required where AC-coupled signals or dual-polarity transients (e.g., RS-485, CAN bus) demand protection in both directions. | Select SMBJ18CA-E3/5B only if bidirectional clamping is needed; unidirectional SMBJ18A-E3/5B offers lower leakage in DC-only applications. |
| SMAJ18A-E3/52 | Same VWM (18 V), VBR (20.0–22.1 V), and VC (29.2 V), but lower PPPM (400 W); SMA (DO-214AC) package with smaller footprint and higher RθJA (140 °C/W). | Suitable for lower-energy transients (IEC 61000-4-2 ESD only) or space-constrained designs where 600 W surge margin is not required. | Choose SMAJ18A-E3/52 only when board area is critical and surge threat level is limited to ESD or low-duty-cycle spikes. |
Compared with SMBJ18CA-E3/5B, the SMBJ18A-E3/5B provides superior leakage performance in DC systems; compared with SMAJ18A-E3/52, it delivers 50% higher surge energy handling and better thermal dissipation-critical for industrial and automotive power rail protection.
Availability
SMBJ18A-E3/5B is available at Aetrix Electronics and suitable for industrial motor drives, automotive body control modules, telecom PoE powered devices, and consumer appliance power supplies requiring stable component supply and repeatable surge protection performance.
Supply support for SMBJ18A-E3/5B 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, power handling, and automotive qualification.
The SMBJ series was developed for robust, high-energy transient suppression in harsh environments-targeting industrial automation, transportation electronics, and infrastructure equipment where failure modes must be mitigated without adding complexity.
FAQ
What is the maximum clamping voltage of SMBJ18A-E3/5B under surge conditions?
The SMBJ18A-E3/5B has a maximum clamping voltage (VC) of 29.2 V when subjected to its rated peak pulse current (IPPM) of 20.5 A using the standardized 10/1000 µs waveform. This value is measured per JEDEC test conditions and defines the upper voltage limit imposed on protected circuitry during transient events. The SMBJ18A-E3/5B maintains this clamping performance across its full operating temperature range.
Is SMBJ18A-E3/5B suitable for automotive applications?
The SMBJ18A-E3/5B is a commercial-grade (E3 suffix), RoHS-compliant part-not AEC-Q101 qualified. For automotive use, Vishay offers the SMBJ18AHE3_B variant (HE3 suffix), which meets AEC-Q101 stress testing requirements. The SMBJ18A-E3/5B remains appropriate for non-safety-critical automotive-adjacent applications such as aftermarket infotainment or accessory modules where qualification is not mandated.
How does the SMBJ18A-E3/5B differ from the SMBJ18CA-E3/5B?
The SMBJ18A-E3/5B is unidirectional, with a cathode band marking and asymmetric conduction (conducts only when anode is negative relative to cathode). The SMBJ18CA-E3/5B is bidirectional, offering identical clamping in both polarities and no polarity marking. Both share identical VWM (18 V), VBR (20.0–22.1 V), VC (29.2 V), and PPPM (600 W), but SMBJ18A-E3/5B exhibits lower reverse leakage in DC applications.
What is the thermal resistance of SMBJ18A-E3/5B, and how does it affect PCB layout?
The SMBJ18A-E3/5B has a typical junction-to-ambient thermal resistance (RθJA) of 100 °C/W when mounted on 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal. To maintain safe junction temperatures during repetitive surges, PCB layout must provide adequate copper area and minimize trace inductance-especially on the anode (ground) path. Reducing pad size or using thinner copper increases RθJA and risks thermal runaway under sustained stress.
Does SMBJ18A-E3/5B meet lead-free soldering standards?
Yes, the SMBJ18A-E3/5B is RoHS-compliant and rated for lead-free reflow soldering per J-STD-020, with a maximum peak temperature of 260 °C (MSL Level 1). Its matte tin-plated leads are solderable per J-STD-002 and JESD 22-B102, and it passes JESD 201 Class 2 whisker testing. No pre-baking is required prior to reflow.
SMBJ18A-E3/5B Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AA, SMB
- 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):
- 20.5A
- Power - Peak Pulse:
- 600W
- 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-214AA (SMBJ)
SMBJ18A-E3/5B FAQ
1.How can I place an order for SMBJ18A-E3/5B through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ18A-E3/5B 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 SMBJ18A-E3/5B reliable?
The price and inventory of SMBJ18A-E3/5B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ18A-E3/5B is usually 5 days.
3.What payment methods are accepted for SMBJ18A-E3/5B?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ18A-E3/5B transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ18A-E3/5B?
SMBJ18A-E3/5B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ18A-E3/5B 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 SMBJ18A-E3/5B?
For technical support, including SMBJ18A-E3/5B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ18A-E3/5B requirements.
6.How does Aetrix verify that SMBJ18A-E3/5B is sourced from the original manufacturer or authorized distributors?
All SMBJ18A-E3/5B 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 SMBJ18A-E3/5B meets industry standards.
7.What is the process for return or replacement of SMBJ18A-E3/5B?
All SMBJ18A-E3/5B units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ18A-E3/5B, 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 SMBJ18A-E3/5B part is unused and in its original packaging.
Return procedure for SMBJ18A-E3/5B:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ18A-E3/5B Tags
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