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Vishay General Semiconductor - Diodes Division SMBJ18A-E3/52
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- Part No.:
- SMBJ18A-E3/52
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ18A-E3/52.pdf
- Description:
- TVS DIODE 18VWM 29.2VC DO214AA
- Quantity:
- Payment:
- Shipping:
Inventory:887
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Product details
Overview
SMBJ18A-E3/52 from Vishay General Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in SMB (DO-214AA) package, designed to protect sensitive electronics against voltage transients induced by inductive load switching and lightning surges. It features a 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, and 600 W peak pulse power rating with 10/1000 µs waveform.
For engineers reviewing the SMBJ18A-E3/52 datasheet, SMBJ18A-E3/52 pinout, SMBJ18A-E3/52 application, or SMBJ18A-E3/52 equivalent, this device is selected for robust overvoltage protection on DC power rails and low-voltage signal lines in industrial control, automotive subsystems, and sensor interfaces where fast response (<1 ps), low clamping ratio, and AEC-Q101-compliant reliability are required.
Technical Context
The SMBJ18A-E3/52 operates as a unidirectional avalanche diode, conducting only in reverse bias above its breakdown threshold to shunt surge energy to ground. Its glass-passivated junction ensures stable VBR tolerance (±5%) and low incremental surge resistance, enabling consistent clamping performance under repetitive 10/1000 µs transients at 0.01% duty cycle.
Thermally, it supports operation from –55 °C to +150 °C junction temperature, with RθJA = 100 °C/W and RθJL = 20 °C/W, and meets MSL Level 1 per J-STD-020 with 260 °C reflow peak. Polarity is marked by a cathode band; no marking on bidirectional variants.
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 systems. |
| VBR (min/max) | 20.0 V / 22.1 V at IT = 1 mA - Tight breakdown window ensures predictable turn-on without premature conduction. |
| VC @ IPPM | 29.2 V at 20.5 A - Clamping voltage limits downstream IC stress during 600 W surge events. |
| PPPM | 600 W - Peak pulse power handling capability with standardized 10/1000 µs waveform. |
| IPPM | 20.5 A - Peak surge current capacity derived from VC and PPPM; validates protection level for IEC 61000-4-5 Level 3. |
| TJ max. | +150 °C - Enables use in under-hood automotive and high-ambient industrial environments. |
| Package | SMB (DO-214AA) - Surface-mount footprint (5.21 mm × 4.06 mm) compatible with automated placement and IPC-7351B land patterns. |
Pinout & Package
Package: SMB (DO-214AA), molded plastic case with matte tin-plated leads, UL 94 V-0 rated. Cathode indicated by a band on the body; anode is unmarked end.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (banded end) | Surge return path | Connected to system ground or low-impedance reference; conducts reverse surge current to clamp voltage. |
| Anode (unbanded end) | Protected line input | Connected to the line being protected (e.g., 24 V supply rail or sensor output); blocks forward current under normal operation. |
Key Features
| Feature | Design Value |
|---|---|
| 600 W peak pulse power (10/1000 µs) | Supports IEC 61000-4-5 surge immunity up to 1 kV/2 Ω on 24 V DC lines without derating. |
| 29.2 V clamping voltage at 20.5 A | Clamping ratio (VC/VWM) = 1.62 - minimizes overvoltage stress on downstream 30 V-rated MOSFETs or regulators. |
| Glass passivated junction | Ensures long-term stability of VBR and leakage (<1 µA at 18 V), critical for battery-powered sensor nodes. |
| MSL Level 1, 260 °C reflow compatible | Enables single-pass lead-free assembly without moisture sensitivity concerns or baking requirements. |
| AEC-Q101 qualified option available | HE3 suffix variant meets automotive-grade reliability for engine control, ADAS camera power rails, and infotainment interfaces. |
Applications
| Industrial Motor Control | Automotive Body Electronics |
|---|---|
|
Use Scenario: Protection of gate drivers and microcontroller I/O pins against back-EMF spikes from solenoid valves and brushed DC motors. IC Role / Device Role / Timing Role: Unidirectional TVS placed between motor driver output and ground to clamp inductive kickback within 1 ns. Use Value: Limits transient voltage to ≤29.2 V, preventing latch-up or oxide breakdown in 3.3 V/5 V logic and 40 V-rated half-bridge drivers. |
Use Scenario: Overvoltage suppression on LIN bus transceiver power supply (VBAT line) in door modules and seat controllers. IC Role / Device Role / Timing Role: Standoff at 18 V allows operation across cold-crank (6 V) to load-dump (40 V) conditions while clamping surges >30 V. Use Value: Withstands 600 W pulses without degradation, meeting ISO 7637-2 Pulse 5a requirements for automotive 12 V systems. |
| Consumer Power Adapters | Industrial Sensor Interfaces |
|
Use Scenario: Secondary-side DC output protection in 24 V wall adapters against ESD and AC line transients coupled through transformer leakage. IC Role / Device Role / Timing Role: Fast-acting shunt element placed across output capacitor to divert surge energy before reaching USB-PD or PoE controller ICs. Use Value: 29.2 V clamping ensures downstream 24 V-rated LDOs and USB-C port controllers remain within absolute maximum ratings. |
Use Scenario: Protection of analog outputs (4–20 mA loop) and digital I/O (RS-485, CAN) in factory-floor pressure/temperature transmitters. IC Role / Device Role / Timing Role: Low-capacitance (≈100 pF) unidirectional TVS on signal lines to avoid signal integrity degradation at 1 Mbps. Use Value: Sub-1 ns response time prevents transient coupling into precision ADC front-ends, maintaining ±0.1% measurement accuracy. |
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-E3/52 | Bidirectional variant; symmetric VBR (20.0–22.1 V) in both polarities; same VC, PPPM, and package. | Required for AC-coupled or floating signal lines (e.g., RS-485, Ethernet PHY) where polarity reversal occurs. | Select SMBJ18CA-E3/52 only when protecting bidirectional signals; SMBJ18A-E3/52 is optimal for DC rails with defined ground reference. |
| SMCJ18A-E3/52 | Larger SMC (DO-214AB) package; identical electrical specs but higher thermal mass (RθJA = 40 °C/W vs. 100 °C/W) and 1500 W PPPM. | Suitable for higher-energy surge environments (e.g., outdoor telecom power inputs) where PCB space permits larger footprint. | Choose SMBJ18A-E3/52 for space-constrained designs needing 600 W protection; upgrade to SMCJ18A-E3/52 only if surge test levels exceed 600 W. |
Compared with SMBJ18CA-E3/52 and SMCJ18A-E3/52, the SMBJ18A-E3/52 provides optimal balance of compact SMB footprint, precise 18 V standoff, and verified 600 W surge handling for cost-sensitive DC power rail protection-without over-engineering package size or polarity capability.
Availability
SMBJ18A-E3/52 is available at Aetrix Electronics and suitable for industrial motor drives, automotive body control modules, and consumer power adapter designs requiring stable component supply and RoHS-compliant manufacturing.
Supply support for SMBJ18A-E3/52 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, and protection devices with emphasis on reliability, efficiency, and application-specific optimization.
The SMBJ series is engineered for high-reliability transient suppression in harsh environments-including automotive, industrial, and telecom-delivering consistent clamping performance across temperature and lifetime.
FAQ
What is the maximum clamping voltage of SMBJ18A-E3/52 at its rated peak pulse current?
The SMBJ18A-E3/52 has a maximum clamping voltage (VC) of 29.2 V at its rated peak pulse current (IPPM) of 20.5 A, measured under the standard 10/1000 µs waveform. This value is guaranteed per Vishay's datasheet revision 09-Jan-2024 (Document Number: 88392) and defines the upper voltage limit imposed on protected circuitry during surge events. The SMBJ18A-E3/52 maintains this clamping performance across its full operating temperature range.
Is SMBJ18A-E3/52 suitable for automotive applications?
The SMBJ18A-E3/52 itself is a commercial-grade part (RoHS-compliant, E3 suffix), but Vishay offers the AEC-Q101-qualified variant SMBJ18AHE3_B/H for automotive use. While SMBJ18A-E3/52 meets key environmental specs (–55 °C to +150 °C TJ, MSL Level 1), only the HE3-suffixed version is certified for automotive qualification testing. For non-safety-critical body electronics, SMBJ18A-E3/52 may be used with customer validation; for production automotive systems, SMBJ18AHE3_B/H is the approved variant.
How does the SMBJ18A-E3/52 differ from the SMBJ18CA-E3/52?
The SMBJ18A-E3/52 is unidirectional, with a cathode band indicating the surge return path to ground, while the SMBJ18CA-E3/52 is bidirectional and lacks polarity marking. Both share identical VWM (18 V), VBR (20.0–22.1 V), VC (29.2 V), and PPPM (600 W), but the CA version clamps symmetrically in both directions. Use SMBJ18A-E3/52 for DC rails with fixed polarity; choose SMBJ18CA-E3/52 for AC or floating differential lines like RS-485 or CAN.
What is the thermal resistance of SMBJ18A-E3/52, and how does it affect layout design?
The SMBJ18A-E3/52 has a typical junction-to-ambient thermal resistance (RθJA) of 100 °C/W and junction-to-lead (RθJL) of 20 °C/W, measured on 0.2" × 0.2" copper pads. This means PCB layout must provide adequate copper area and thermal vias to maintain TJ ≤ 150 °C under sustained 5.0 W power dissipation. For high-reliability designs, doubling pad size or adding 4–6 thermal vias per pad reduces effective RθJA and extends surge endurance. The SMBJ18A-E3/52 datasheet specifies minimum pad dimensions in inches and millimeters.
Does SMBJ18A-E3/52 require a heatsink for standard surge protection use?
No, the SMBJ18A-E3/52 does not require an external heatsink for transient suppression because its 600 W peak pulse power is applied for extremely short durations (≤1000 µs), and average power dissipation remains negligible. Its 5.0 W steady-state power rating (PD) applies only to continuous DC conditions-not surge events. In normal operation, the SMBJ18A-E3/52 self-cools between transients; thermal design focuses on PCB copper thermal mass, not heatsinks. Heatsinking is unnecessary unless the SMBJ18A-E3/52 is subjected to frequent repetitive surges exceeding 0.01% duty cycle.
SMBJ18A-E3/52 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-E3/52 FAQ
1.How can I place an order for SMBJ18A-E3/52 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ18A-E3/52 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-E3/52 reliable?
The price and inventory of SMBJ18A-E3/52 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ18A-E3/52 is usually 5 days.
3.What payment methods are accepted for SMBJ18A-E3/52?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ18A-E3/52 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ18A-E3/52?
SMBJ18A-E3/52 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ18A-E3/52 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-E3/52?
For technical support, including SMBJ18A-E3/52 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ18A-E3/52 requirements.
6.How does Aetrix verify that SMBJ18A-E3/52 is sourced from the original manufacturer or authorized distributors?
All SMBJ18A-E3/52 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-E3/52 meets industry standards.
7.What is the process for return or replacement of SMBJ18A-E3/52?
All SMBJ18A-E3/52 units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ18A-E3/52, 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-E3/52 part is unused and in its original packaging.
Return procedure for SMBJ18A-E3/52:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ18A-E3/52 Tags
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