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Vishay General Semiconductor - Diodes Division SMB8J18CAHM3/I
- Part No.:
- SMB8J18CAHM3/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMB8J18CAHM3/I.pdf
- Description:
- TVS DIODE 18VWM 29.2VC DO214AA
- Quantity:
- Payment:
- Shipping:
Inventory:5,076
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Product details
Overview
SMB8J18CAHM3/I from Vishay General Semiconductor is a bidirectional transient voltage suppressor (TVS) diode in SMB (DO-214AA) package, designed for high-energy surge protection on signal and power lines. It features a 18 V stand-off voltage (VWM), 29.2 V maximum clamping voltage (VC) at 27.4 A peak pulse current (IPPM), and 800 W peak pulse power (PPPM) with 10/1000 µs waveform - optimized for automotive sensor interfaces and industrial I/O protection.
For engineers reviewing the SMB8J18CAHM3/I datasheet, SMB8J18CAHM3/I pinout, SMB8J18CAHM3/I application, or SMB8J18CAHM3/I equivalent, this device is selected for robust ESD and lightning surge immunity in AEC-Q101-compliant systems where low clamping voltage, fast response (<1 ns), and halogen-free RoHS compliance are mandatory design requirements.
Technical Context
This bidirectional TVS operates symmetrically across both polarities, enabling protection of AC-coupled or differential signal paths without polarity constraints. Its glass-passivated junction ensures stable breakdown behavior and low leakage (<1 µA at VWM), while MSL Level 1 moisture sensitivity supports lead-free reflow up to 260 °C.
The device delivers 800 W peak pulse power under standardized 10/1000 µs transients, with thermal resistance RθJA = 72 °C/W and RθJL = 20 °C/W - confirming suitability for PCB layouts with minimal copper pad area (0.2" × 0.2") and sustained operation up to TJ = +150 °C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - maximum continuous reverse operating voltage before clamping begins; defines safe signal swing range for protected line. |
| VBR min / max | 20.0 V / 22.1 V at IT = 1 mA - guaranteed breakdown onset window ensures predictable turn-on during transients. |
| VC @ IPPM | 29.2 V at IPPM = 27.4 A - clamping voltage limits downstream IC stress during 800 W surge events. |
| PPPM | 800 W (10/1000 µs) - energy-handling capacity sufficient for ISO 7637-2 Pulse 1/2a/5a and IEC 61000-4-5 Level 3 surges. |
| ID @ VWM | ≤1.0 µA - ultra-low leakage preserves signal integrity and battery life in always-on sensor nodes. |
| TJ max | +150 °C - enables deployment in under-hood automotive environments and industrial enclosures without derating. |
| AEC-Q101 | Qualified - validated for automotive-grade reliability including temperature cycling, HTRB, and ESD (HBM ≥8 kV). |
Pinout & Package
Package: SMB (DO-214AA), surface-mount, halogen-free, RoHS-compliant, matte tin-plated leads. Dimensions: 4.57 mm × 3.94 mm × 2.20 mm (L × W × H). Molding compound meets UL 94 V-0.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (marked end) | Reference node for bidirectional conduction | No functional polarity marking on bidirectional types; terminals are symmetrical - either lead may serve as anode/cathode depending on transient polarity. |
| Anode | Reference node for bidirectional conduction | Identical electrical behavior to cathode terminal; device conducts equally in both directions above VBR. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables single-device protection of AC signals, differential buses (e.g., CAN, RS-485), and ungrounded sensor outputs without polarity concerns. |
| AEC-Q101 qualification | Validated for automotive applications including engine control units, ADAS camera modules, and body electronics requiring zero field failure risk. |
| Halogen-free & RoHS-compliant (HM3 suffix) | Meets global environmental regulations and eliminates corrosive halogen emissions during soldering or end-of-life incineration. |
| Low clamping ratio (VC/VBR ≈ 1.32) | Minimizes overvoltage exposure to downstream ICs - critical for protecting 3.3 V or 5 V logic interfaces with tight absolute maximum ratings. |
| MSL Level 1 rating | Supports standard SMT reflow profiles up to 260 °C peak without baking or special handling - reduces manufacturing cost and complexity. |
Applications
| Automotive Sensor Interface | Industrial Digital I/O Protection |
|---|---|
Use Scenario: Protecting LIN bus transceivers and analog sensor outputs (e.g., pressure, temperature) in engine control modules against load dump and inductive switching noise. IC Role / Device Role / Timing Role: Bidirectional voltage clamp placed directly at connector entry point to shunt transients before reaching MCU ADC or LIN PHY. Use Value: Clamps 800 W surges to ≤29.2 V, preventing latch-up or gate oxide damage in 5 V tolerant automotive microcontrollers. |
Use Scenario: Safeguarding PLC digital input channels connected to 24 V DC field sensors exposed to relay coil flyback and ESD events. IC Role / Device Role / Timing Role: Primary surge suppression element mounted adjacent to terminal block, absorbing repetitive 10/1000 µs transients per IEC 61000-4-4. Use Value: Maintains <1 µA leakage at 18 V, ensuring reliable detection of low-current dry-contact closures without false triggering. |
| USB Type-C Port Protection | RS-485 Transceiver Interface |
Use Scenario: Shielding USB Type-C CC and VCONN lines from ESD (±15 kV contact) and hot-swap voltage overshoot in portable docking stations. IC Role / Device Role / Timing Role: Low-capacitance TVS placed inline with CC logic lines to suppress fast transients without distorting 300 kHz signaling. Use Value: Sub-100 pF junction capacitance (typ.) preserves signal edge integrity while clamping ESD pulses within nanoseconds. |
Use Scenario: Protecting half-duplex RS-485 transceivers (e.g., SN65HVD230) in factory automation networks from cable-induced lightning surges. IC Role / Device Role / Timing Role: Common-mode surge suppressor bridging A/B lines to ground, limiting differential-mode overvoltage via symmetrical clamping. Use Value: Matches differential impedance and withstands repeated 4 kV IEC 61000-4-5 surges without parameter shift or degradation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMB8J18CAHE3/I | Same electrical specs and package, but RoHS-compliant commercial grade (not halogen-free); no AEC-Q101 qualification. | Suitable for non-automotive industrial or consumer designs where halogen-free mandate or automotive qualification is not required. | Select SMB8J18CAHE3/I when cost optimization is prioritized and AEC-Q101/halogen-free compliance is unnecessary. |
| SMAJ18CA | Same VWM (18 V) and VC (29.2 V), but lower PPPM (400 W) and smaller SMA package (DO-214AC); higher RθJA (110 °C/W). | Limited to lower-energy transients (e.g., IEC 61000-4-2 ESD only); unsuitable for ISO 7637-2 or IEC 61000-4-5 Level 3. | Choose SMAJ18CA only for space-constrained, low-power applications where 800 W surge capability is not needed. |
Compared with SMB8J18CAHE3/I, the SMB8J18CAHM3/I adds halogen-free construction and AEC-Q101 validation - essential for Tier 1 automotive supply chains. Against SMAJ18CA, it provides double the surge power rating and superior thermal performance, enabling use in harsher electromagnetic environments.
Availability
SMB8J18CAHM3/I is available at Aetrix Electronics and suitable for automotive sensor protection, industrial I/O hardening, and RS-485 interface safeguarding requiring stable component supply across multi-year production cycles.
Supply support for SMB8J18CAHM3/I 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 performance.
The SMB8JxxCA series is part of Vishay's TRANSZORB® TVS platform, engineered specifically for high-reliability transient suppression in automotive, industrial, and communications infrastructure where AEC-Q101 compliance and precise clamping are critical.
FAQ
What is the clamping voltage of SMB8J18CAHM3/I at its rated peak pulse current?
The SMB8J18CAHM3/I has a maximum clamping voltage (VC) of 29.2 V when subjected to its peak pulse current (IPPM) of 27.4 A under a 10/1000 µs waveform. This value is measured per ANSI/IEEE C62.35 and guarantees that downstream circuitry sees no more than 29.2 V during an 800 W transient event - a key parameter for protecting 3.3 V or 5 V logic interfaces. The SMB8J18CAHM3/I maintains this clamping performance across its full operating temperature range (-55 °C to +150 °C).
Is SMB8J18CAHM3/I suitable for automotive applications?
Yes, SMB8J18CAHM3/I is AEC-Q101 qualified and manufactured with halogen-free, RoHS-compliant materials (HM3 suffix), making it approved for automotive use in engine control units, ADAS sensors, and body electronics. Its qualification includes stress testing for temperature cycling, high-temperature reverse bias, and ESD (HBM ≥8 kV). The SMB8J18CAHM3/I is explicitly listed in Vishay's automotive ordering matrix with HE3/HM3 suffixes denoting qualification status.
How does SMB8J18CAHM3/I differ from unidirectional variants like SMB10J18A?
The SMB8J18CAHM3/I is bidirectional with symmetrical breakdown (20.0–22.1 V in both directions) and 800 W PPPM, whereas SMB10J18A is unidirectional with 1000 W PPPM and forward conduction capability. The SMB8J18CAHM3/I lacks polarity marking and protects AC or differential signals without orientation constraints, while SMB10J18A requires correct cathode alignment and handles higher single-polarity surges. Their SMB packages are identical, but electrical behavior and application scope differ fundamentally.
What is the maximum reverse leakage current for SMB8J18CAHM3/I at its stand-off voltage?
The SMB8J18CAHM3/I exhibits a maximum reverse leakage current (ID) of 1.0 µA at its stand-off voltage (VWM) of 18 V, measured at TA = 25 °C. This ultra-low leakage ensures minimal power loss and signal distortion in always-on circuits such as automotive wake-up lines or battery-powered IoT sensor nodes. Leakage remains below 5 µA even at +125 °C, supporting stable operation across extended temperature ranges.
Does SMB8J18CAHM3/I require special PCB layout considerations?
Yes - Vishay specifies mounting on minimum 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal to achieve rated 800 W pulse power and thermal performance. Smaller pads increase thermal resistance and reduce surge capability. The SMB8J18CAHM3/I also requires symmetric trace routing for bidirectional protection and should be placed as close as possible to the protected interface connector to minimize inductance. No polarity orientation is needed due to its bidirectional symmetry.
SMB8J18CAHM3/I Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AA, SMB
- Series:
- TransZorb®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 18V
- Voltage - Breakdown (Min):
- 20V
- Voltage - Clamping (Max) @ Ipp:
- 29.2V
- Current - Peak Pulse (10/1000µs):
- 27.4A
- Power - Peak Pulse:
- 800W
- Power Line Protection:
- No
- Applications:
- Telecom
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AA (SMB)
SMB8J18CAHM3/I FAQ
1.How can I place an order for SMB8J18CAHM3/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SMB8J18CAHM3/I 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 SMB8J18CAHM3/I reliable?
The price and inventory of SMB8J18CAHM3/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMB8J18CAHM3/I is usually 5 days.
3.What payment methods are accepted for SMB8J18CAHM3/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMB8J18CAHM3/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMB8J18CAHM3/I?
SMB8J18CAHM3/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMB8J18CAHM3/I 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 SMB8J18CAHM3/I?
For technical support, including SMB8J18CAHM3/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMB8J18CAHM3/I requirements.
6.How does Aetrix verify that SMB8J18CAHM3/I is sourced from the original manufacturer or authorized distributors?
All SMB8J18CAHM3/I 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 SMB8J18CAHM3/I meets industry standards.
7.What is the process for return or replacement of SMB8J18CAHM3/I?
All SMB8J18CAHM3/I units undergo pre-shipment inspection (PSI). If there is an issue with SMB8J18CAHM3/I, 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 SMB8J18CAHM3/I part is unused and in its original packaging.
Return procedure for SMB8J18CAHM3/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMB8J18CAHM3/I Tags
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