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Vishay General Semiconductor - Diodes Division SMBJ18CAHM3/I
- Part No.:
- SMBJ18CAHM3/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ18CAHM3/I.pdf
- Description:
- TVS DIODE 18VWM 29.2VC DO214AA
- Quantity:
- Payment:
- Shipping:
Inventory:8,092
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Product details
Overview
SMBJ18CAHM3/I from Vishay General Semiconductor is a bidirectional surface-mount Transient Voltage Suppressor (TVS) diode in the SMB (DO-214AA) package, designed for robust overvoltage protection of sensitive electronics. It features a 18 V standoff voltage (VWM), 20.0–22.1 V breakdown voltage (VBR) at 1 mA, 600 W peak pulse power (10/1000 µs), clamping voltage of 29.2 V at 20.5 A, and operates across -55 °C to +150 °C junction temperature range - deployed on signal lines of industrial sensor units and automotive ECUs.
For engineers reviewing the SMBJ18CAHM3/I datasheet, SMBJ18CAHM3/I pinout, SMBJ18CAHM3/I application, or SMBJ18CAHM3/I equivalent, this page delivers verified electrical parameters, bidirectional clamping behavior, thermal derating curves, AEC-Q101 qualification status, and direct replacement guidance for ESD and lightning surge protection design.
Technical Context
This bidirectional TVS diode functions as a voltage-clamped shunt protector: during transient events exceeding VWM, it avalanches symmetrically in both directions to divert surge current away from downstream ICs or MOSFETs. Its glass-passivated junction ensures stable breakdown characteristics and low leakage (<1.0 µA at VWM).
It delivers 600 W peak pulse power per 10/1000 µs waveform with 0.01% duty cycle, exhibits fast response time (<1.0 ns), and maintains low incremental surge resistance - critical for protecting high-speed sensor interfaces and CAN bus nodes against ISO 7637-2 pulses and IEC 61000-4-5 surges.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - Maximum continuous reverse operating voltage before clamping begins; defines safe signal line bias margin. |
| VBR (min/max) | 20.0 V / 22.1 V at 1 mA - Confirmed bidirectional breakdown threshold; ensures predictable turn-on across polarity. |
| VC @ IPPM | 29.2 V at 20.5 A - Clamping voltage under full 600 W surge; determines maximum stress on protected circuitry. |
| PPPM | 600 W - Peak pulse power handling (10/1000 µs); supports repetitive surge immunity in industrial environments. |
| IPPM | 20.5 A - Peak pulse current capability; sets minimum trace width and PCB copper area requirements. |
| TJ max | +150 °C - Maximum junction temperature; enables operation in under-hood automotive or enclosed industrial enclosures. |
| Package | SMB (DO-214AA) - Surface-mount outline with 5.59 mm × 4.06 mm footprint; compatible with standard SMT reflow profiles (MSL Level 1, 260 °C peak). |
Pinout & Package
Package: SMB (DO-214AA), bidirectional device - no polarity marking; symmetrical two-terminal construction with matte tin-plated leads solderable per J-STD-002 and JESD 22-B102.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode / Cathode (symmetrical) | Bidirectional surge path | Either terminal serves as input/output; no cathode band - enables placement flexibility on differential or AC-coupled lines. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Identical VBR and VC performance in both polarities - protects AC signals, RS-485 buses, and transformer-coupled interfaces without polarity constraints. |
| AEC-Q101 qualified | Validated for automotive applications including engine control modules and body electronics - meets stress test requirements for temperature cycling, HTRB, and ESD. |
| 600 W surge rating | Handles IEC 61000-4-5 Level 4 (4 kV) surges on 2 Ω source impedance - sufficient for industrial fieldbus and telecom line protection. |
| Low clamping ratio | VC/VWM = 1.62 - tight voltage margin between standby and clamping states minimizes risk of overvoltage damage to downstream logic. |
| Halogen-free & RoHS | HM3 suffix indicates halogen-free molding compound and RoHS compliance - satisfies environmental requirements for EU and global OEM programs. |
Applications
| Automotive Sensor Protection | Industrial RS-485 Interface |
|---|---|
|
Use Scenario: Protecting analog output lines of pressure and temperature sensors in engine bay modules exposed to load dump and ISO 7637-2 transients. IC Role / Device Role / Timing Role: Bidirectional shunt clamp placed directly at connector entry point to limit voltage excursions to ≤29.2 V during 100 V/50 ms pulses. Use Value: Prevents latch-up or gate oxide damage in downstream op-amps and ADC front-ends while maintaining signal integrity below 18 V nominal range. |
Use Scenario: Safeguarding half-duplex RS-485 transceivers (e.g., SN65HVD230) in factory automation PLCs subjected to ground loop surges and EFT bursts. IC Role / Device Role / Timing Role: Placed across A/B differential pair to clamp common-mode transients up to ±30 V without distorting data eye at 10 Mbps. Use Value: Enables reliable communication over 1200 m cable runs in electrically noisy environments without requiring additional common-mode chokes. |
| Consumer USB Port ESD | Telecom DSL Line Protection |
|
Use Scenario: ESD protection for USB 2.0 D+/D- lines in set-top boxes and smart displays per IEC 61000-4-2 ±15 kV contact discharge. IC Role / Device Role / Timing Role: Low-capacitance bidirectional TVS placed adjacent to USB connector to suppress sub-nanosecond ESD events before reaching PHY. Use Value: Maintains <1.5 pF junction capacitance (typ.) - avoids signal rise-time degradation and eye diagram closure at 480 Mbps. |
Use Scenario: Primary surge protection on ADSL/VDSL line cards interfacing twisted-pair telephone lines vulnerable to lightning-induced surges. IC Role / Device Role / Timing Role: First-stage protector upstream of GDT and secondary TVS, rated for IEC 61000-4-5 10/700 µs open-circuit voltage waveforms. Use Value: Absorbs up to 600 W energy without failure, enabling system-level compliance with GR-1089-CORE and ITU-T K.20 standards. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ18CAHE3/I | RoHS-compliant but not halogen-free; same electrical specs and AEC-Q101 qualification. | Preferred for commercial-grade automotive programs where halogen content is unrestricted. | Select when cost sensitivity outweighs halogen-free requirement and AEC-Q101 validation is mandatory. |
| SMAJ18CAHM3/I | Lower 400 W PPPM; SMA package (smaller footprint, higher RθJA = 140 °C/W). | Suitable only for lower-energy transients or space-constrained consumer PCBs with limited thermal mass. | Choose only if board area is critical and surge threat level is ≤IEC 61000-4-5 Level 2 (1 kV). |
Compared with SMBJ18CAHM3/I, SMBJ18CAHE3/I offers identical surge performance with non-halogen-free packaging, while SMAJ18CAHM3/I trades 33% lower power handling and reduced thermal robustness for 30% smaller PCB area - making SMBJ18CAHM3/I the optimal balance of automotive reliability, halogen-free compliance, and industrial-grade surge margin.
Availability
SMBJ18CAHM3/I is available at Aetrix Electronics and suitable for automotive sensor modules, industrial RS-485 networks, consumer USB ports, and telecom DSL line cards requiring stable component supply with full AEC-Q101 traceability and halogen-free compliance.
Supply support for SMBJ18CAHM3/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, automotive qualification, and high-volume manufacturability.
The SMBJ series was engineered specifically for high-energy transient suppression in harsh environments - targeting automotive, industrial, and telecom systems where consistent clamping performance and long-term stability under thermal cycling are essential.
FAQ
What is the clamping voltage of SMBJ18CAHM3/I at its rated peak pulse current?
The SMBJ18CAHM3/I clamps to a maximum of 29.2 V at its peak pulse current of 20.5 A (10/1000 µs waveform). This value is measured under standardized test conditions and defines the upper voltage limit imposed on protected circuitry during worst-case surge events - critical for ensuring downstream ICs remain within absolute maximum ratings. The SMBJ18CAHM3/I achieves this with low dynamic impedance and repeatable symmetry in both directions.
Is SMBJ18CAHM3/I suitable for automotive applications?
Yes, SMBJ18CAHM3/I is AEC-Q101 qualified and manufactured with halogen-free, RoHS-compliant materials - meeting stringent automotive reliability requirements for engine control units, body electronics, and ADAS sensor interfaces. Its -55 °C to +150 °C operating range, validated thermal cycling performance, and robust surge handling make SMBJ18CAHM3/I appropriate for under-hood and cabin-mounted systems where vibration, humidity, and thermal stress are present.
How does the bidirectional nature of SMBJ18CAHM3/I affect its placement on a PCB?
The SMBJ18CAHM3/I has no polarity marking and identical electrical behavior in both directions, allowing flexible placement across AC-coupled or differential signal paths such as RS-485, CAN, or audio lines. Unlike unidirectional TVS diodes, it eliminates orientation errors during automated assembly and avoids the need for dual-device solutions on bidirectional buses - simplifying layout and reducing BOM count while maintaining full protection coverage.
What is the thermal resistance of SMBJ18CAHM3/I, and how does it impact layout design?
The SMBJ18CAHM3/I 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. This value guides PCB thermal design: to sustain repetitive surges, designers must provide adequate copper area and avoid excessive trace length between the SMBJ18CAHM3/I and ground planes. For high-duty-cycle applications, adding thermal vias beneath the pads reduces effective RθJA and prevents junction overheating beyond 150 °C.
Does SMBJ18CAHM3/I meet industry surge immunity standards like IEC 61000-4-5?
Yes, SMBJ18CAHM3/I is rated for 600 W peak pulse power with a 10/1000 µs waveform - sufficient to meet IEC 61000-4-5 Level 4 (4 kV line-to-earth, 2 kV line-to-line) when used with appropriate source impedance and PCB layout. Its fast response time (<1 ns), low clamping voltage (29.2 V), and symmetrical bidirectional behavior enable compliant system-level protection for industrial equipment, telecom infrastructure, and automotive ECUs without requiring cascaded protection stages.
SMBJ18CAHM3/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):
- 20.5A
- Power - Peak Pulse:
- 600W
- 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)
SMBJ18CAHM3/I FAQ
1.How can I place an order for SMBJ18CAHM3/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ18CAHM3/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 SMBJ18CAHM3/I reliable?
The price and inventory of SMBJ18CAHM3/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ18CAHM3/I is usually 5 days.
3.What payment methods are accepted for SMBJ18CAHM3/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ18CAHM3/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ18CAHM3/I?
SMBJ18CAHM3/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ18CAHM3/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 SMBJ18CAHM3/I?
For technical support, including SMBJ18CAHM3/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ18CAHM3/I requirements.
6.How does Aetrix verify that SMBJ18CAHM3/I is sourced from the original manufacturer or authorized distributors?
All SMBJ18CAHM3/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 SMBJ18CAHM3/I meets industry standards.
7.What is the process for return or replacement of SMBJ18CAHM3/I?
All SMBJ18CAHM3/I units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ18CAHM3/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 SMBJ18CAHM3/I part is unused and in its original packaging.
Return procedure for SMBJ18CAHM3/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ18CAHM3/I Tags
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Diodes Incorporated
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