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Taiwan Semiconductor Corporation SMBJ18C
- Part No.:
- SMBJ18C
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ18C.pdf
- Description:
- 600W, 22.2V, 10%, BIDIRECTIONAL,
- Quantity:
- Payment:
- Shipping:
Inventory:5,344
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Product details
Overview
SMBJ18C from Taiwan Semiconductor is a unidirectional 600W surface-mount transient voltage suppressor (TVS) diode in DO-214AA (SMB) package, designed for high-energy ESD and surge protection in automotive and industrial power rails. It features a 18V working stand-off voltage (VWM), 20.0–24.4V breakdown voltage (VBR @ 1mA), 32.2V maximum clamping voltage (VC) at 19.5A peak pulse current, and <1μA leakage above 10V - deployed in CAN bus power line protection and DC/DC converter input stages.
For engineers reviewing the SMBJ18C datasheet, SMBJ18C pinout, SMBJ18C application, or SMBJ18C equivalent, key selection criteria include clamping performance under ISO 7637-2 Pulse 1/2a/2b/3a/3b waveforms, junction-to-ambient thermal resistance (55°C/W), moisture sensitivity level (MSL 1), and compatibility with automated SMT placement on 1.6mm PCB thickness.
Technical Context
The SMBJ18C employs a glass-passivated silicon junction optimized for fast transient response (<1.0ps), enabling effective suppression of EFT bursts and lightning-induced surges. Its unidirectional configuration provides low forward voltage drop (VF = 3.5V @ 50A) while maintaining tight VBR tolerance (±10% typical) across temperature.
Thermally, it supports continuous operation up to TJ = +150°C with RθJA = 55°C/W and RθJC = 10°C/W, and meets JESD201 Class 2 whisker resistance and UL 94V-0 flammability requirements for molded compound - critical for under-hood automotive modules and industrial PLC I/O protection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - Maximum continuous reverse operating voltage before significant leakage; sets minimum system rail margin for reliable standby blocking. |
| VBR min/max | 20.0 / 24.4 V @ 1 mA - Confirmed breakdown range ensures predictable turn-on during transients without premature conduction during normal operation. |
| VC @ IPP | 32.2 V @ 19.5 A - Clamping voltage measured with 10/1000µs waveform; defines worst-case overvoltage seen by protected downstream ICs. |
| PPK | 600 W - Peak pulse power rating per single 10/1000µs surge; determines survivability against ISO 7637-2 Pulse 5a (load dump). |
| ID @ VWM | <1 µA - Reverse leakage at rated stand-off voltage; enables low-power system monitoring circuits to remain functional during standby. |
| TJ max | +150 °C - Maximum junction temperature; allows operation in engine control units and motor drives without derating at ambient ≤125°C. |
Pinout & Package
DO-214AA (SMB) surface-mount package: 2-terminal, cathode-banded unidirectional configuration; body dimensions 4.57 × 3.94 × 2.29 mm; matte tin-plated leads compliant with J-STD-002 solderability; polarity marked by cathode band.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to ground or low-impedance return path; forms current sink during transient clamping events. |
| Cathode | High-side input terminal | Connected to protected line (e.g., 12V battery rail); blocks reverse current until VBR exceeded, then conducts surge to anode. |
Key Features
| Feature | Design Value |
|---|---|
| Clamping performance | VC = 32.2 V @ 19.5 A (10/1000µs) - limits overvoltage to safe levels for 3.3V/5V logic interfaces downstream of DC/DC converters. |
| Response time | <1.0 ps - enables suppression of sub-nanosecond ESD events per IEC 61000-4-2 Level 4 (15 kV air, 8 kV contact). |
| Automated placement support | DO-214AA (SMB) footprint with MSL 1 rating - compatible with standard SMT reflow profiles and high-speed pick-and-place machines without baking. |
| Environmental compliance | RoHS-compliant, halogen-free per IEC 61249-2-21, UL 94V-0 molding compound - satisfies automotive PPAP and industrial safety certifications. |
Applications
| Automotive Power Line Protection | Industrial Sensor Interface Protection |
|---|---|
Use Scenario: 12V battery rail in engine control unit exposed to load dump (ISO 7637-2 Pulse 5a) and alternator ripple. IC Role / Device Role / Timing Role: Unidirectional TVS placed between battery input and DC/DC converter input to clamp surges before regulation stage. Use Value: Withstands 600W peak pulses and clamps to ≤32.2V, preventing damage to 40V-rated buck controller ICs and preserving system uptime. |
Use Scenario: 24V analog sensor signal line (e.g., pressure transducer) routed through noisy factory floor wiring. IC Role / Device Role / Timing Role: Bidirectional protection (via SMBJ18CA variant) across differential pair to suppress EFT bursts per IEC 61000-4-4. Use Value: Sub-1ps response captures fast transients before op-amp input stages saturate, maintaining measurement accuracy during EMC testing. |
| LED Driver Input Protection | RS-485 Transceiver Bus Protection |
Use Scenario: Constant-current LED driver powered from 24V industrial supply subject to inductive switching noise. IC Role / Device Role / Timing Role: SMBJ18C placed across input capacitor to absorb repetitive 600W surges from relay coil back-EMF. Use Value: 100A IFSM rating and 3W steady-state dissipation allow repeated surge handling without thermal runaway in enclosed luminaires. |
Use Scenario: RS-485 transceiver (e.g., THVD1550) connected to long field cables in building automation systems. IC Role / Device Role / Timing Role: Unidirectional TVS on VCC line and bidirectional variants on A/B lines to meet IEC 61000-4-5 surge immunity (4kV common-mode). Use Value: 32.2V clamping prevents latch-up in transceiver's internal LDO while maintaining signal integrity up to 20 Mbps. |
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 | Lower VBR range (20.0–22.1 V vs. 20.0–24.4 V); tighter tolerance; same VC = 29.2 V @ 21.5 A. | Better suited for precision 18V rail protection where lower clamping variance improves margin for 3.3V logic supplies. | Select SMBJ18A when tighter VBR distribution and lower clamping voltage are prioritized over absolute peak surge energy handling. |
| SAC18 | Same VWM (18V), but higher PPK = 1500W; larger DO-214AB (SMC) package; VC = 35.5 V @ 42.3 A. | Required where ISO 7637-2 Pulse 5a energy exceeds 600W capability - e.g., heavy-duty truck battery systems. | Choose SAC18 only if board space permits larger SMC footprint and system-level surge testing demands >600W rating. |
Compared with SMBJ18C, SMBJ18A offers improved VBR consistency and lower clamping for tighter voltage margins, while SAC18 trades package size for higher surge capacity - neither is pin-compatible, but both serve adjacent design requirements in automotive and industrial transient protection.
Availability
SMBJ18C is available at Aetrix Electronics and suitable for automotive power line protection, industrial sensor interface protection, and LED driver input protection requiring stable component supply across extended temperature ranges and high-reliability production cycles.
Supply support for SMBJ18C 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
Taiwan Semiconductor Corporation (TSC) is a vertically integrated analog and discrete semiconductor manufacturer headquartered in Hsinchu, Taiwan, serving global automotive, industrial, and consumer markets since 1979.
The SMBJ series was developed specifically for robust, high-power transient suppression in harsh environments - emphasizing low clamping ratio, MSL 1 reliability, and full ISO 7637-2 compliance for automotive-grade front-end protection.
FAQ
What is the clamping voltage of SMBJ18C and how is it measured?
The SMBJ18C has a maximum clamping voltage (VC) of 32.2 V, measured at 19.5 A peak pulse current using the standardized 10/1000 µs double-exponential surge waveform per IEC 61000-4-5. This value represents the highest voltage that will appear across the SMBJ18C terminals during a defined transient event, directly protecting downstream components such as DC/DC controllers and microcontrollers from overvoltage stress.
Is SMBJ18C unidirectional or bidirectional, and how does that affect circuit placement?
SMBJ18C is a unidirectional TVS diode, indicated by the "C" suffix and cathode band marking. It must be placed with cathode toward the protected line (e.g., 12V rail) and anode to ground - conducting only during positive transients. For bidirectional protection (e.g., data lines), the SMBJ18CA variant is required. Incorrect orientation of SMBJ18C would block intended surge paths and compromise system immunity.
Does SMBJ18C meet automotive surge immunity standards like ISO 7637-2?
Yes, SMBJ18C is explicitly rated to meet ISO 7637-2 test pulses 1, 2a, 2b, 3a, and 3b - covering common automotive transient scenarios including load dump simulation, battery disconnect spikes, and inductive switching noise. Its 600W peak power rating and 32.2V clamping ensure compliance when used with appropriate PCB layout and grounding per ISO 11452-4 guidelines.
What is the thermal resistance and maximum junction temperature of SMBJ18C?
SMBJ18C has a junction-to-ambient thermal resistance (RθJA) of 55°C/W and a maximum junction temperature (TJ) of +150°C. These values mean that at 25°C ambient and full 3W steady-state dissipation, the junction rises ~165°C - exceeding limit - so SMBJ18C is intended for transient-only duty. In real-world use, its short-pulse nature keeps average power low, enabling reliable operation in under-hood environments up to +125°C ambient.
How does SMBJ18C compare to SMBJ18A in terms of breakdown voltage and application suitability?
SMBJ18C has a VBR range of 20.0–24.4 V, while SMBJ18A is tighter at 20.0–22.1 V. Both share the same 18V VWM and DO-214AA package, but SMBJ18A achieves lower clamping voltage (29.2 V vs. 32.2 V) due to its narrower VBR spread. SMBJ18C is preferred where broader surge energy tolerance is needed; SMBJ18A suits designs demanding tighter voltage margins, such as 18V-powered FPGAs or precision ADC references.
SMBJ18C Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- DO-214AA, SMB
- Series:
- SMBJ
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 18V
- Voltage - Breakdown (Min):
- 20V
- Voltage - Clamping (Max) @ Ipp:
- 32.2V
- Current - Peak Pulse (10/1000µs):
- 19.5A
- 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 (SMB)
SMBJ18C FAQ
1.How can I place an order for SMBJ18C through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ18C 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 SMBJ18C reliable?
The price and inventory of SMBJ18C are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ18C is usually 5 days.
3.What payment methods are accepted for SMBJ18C?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ18C transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ18C?
SMBJ18C orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ18C 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 SMBJ18C?
For technical support, including SMBJ18C datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ18C requirements.
6.How does Aetrix verify that SMBJ18C is sourced from the original manufacturer or authorized distributors?
All SMBJ18C 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 SMBJ18C meets industry standards.
7.What is the process for return or replacement of SMBJ18C?
All SMBJ18C units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ18C, 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 SMBJ18C part is unused and in its original packaging.
Return procedure for SMBJ18C:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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