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Taiwan Semiconductor Corporation SMBJ12
- Part No.:
- SMBJ12
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ12.pdf
- Description:
- 600W, 14.8V, 10%, UNIDIRECTIONAL
- Quantity:
- Payment:
- Shipping:
Inventory:6,430
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Product details
Overview
SMBJ12 from Taiwan Semiconductor is a unidirectional 600W surface-mount transient voltage suppressor (TVS) diode in DO-214AA (SMB) package, designed for high-energy surge protection in DC power rails and signal lines. It features a 12V working stand-off voltage (VWM), 13.3–16.3V breakdown voltage (VBR @ 1mA), 22.0V maximum clamping voltage (VC) at 28A peak pulse current, and <1μA leakage above 12V - ideal for protecting automotive body control modules against ISO 7637-2 Pulse 1/2a/2b/3a/3b transients.
For engineers reviewing the SMBJ12 datasheet, SMBJ12 pinout, SMBJ12 application, or SMBJ12 equivalent, key selection criteria include clamping performance under 10/1000µs surges, thermal derating above 25°C ambient, unidirectional polarity marking, and compatibility with automated SMT placement on industrial power supplies and automotive ECUs.
Technical Context
The SMBJ12 operates as a silicon avalanche diode with glass-passivated junction, enabling fast response (<1.0ps) to ESD and lightning-induced transients. Its unidirectional configuration provides low forward voltage drop (VF = 3.5V @ 50A) and supports bidirectional protection only when paired with complementary devices or selected as bipolar variants (e.g., SMBJ12C).
Thermal design relies on RθJC = 10°C/W and RθJA = 55°C/W, limiting steady-state power dissipation to 3W at 25°C ambient. Derating per Fig.2 applies above 25°C, and junction temperature must remain within –55°C to +150°C across storage and operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 12 V - Maximum continuous DC or RMS voltage the device blocks without conduction. |
| VBR min/max | 13.3 V / 16.3 V @ 1 mA - Ensures reliable avalanche initiation within defined tolerance band for consistent clamping onset. |
| VC @ IPP | 22.0 V @ 28 A (10/1000 µs) - Peak voltage seen by protected circuit during worst-case surge; defines minimum system overvoltage margin. |
| PPK | 600 W - Non-repetitive peak pulse power handling capability; determines survivability of single high-energy events. |
| ID @ VWM | <1 µA - Low leakage preserves efficiency in battery-powered or high-impedance sensing circuits. |
| TJ max | +150 °C - Enables operation in under-hood automotive environments and industrial enclosures without forced cooling. |
Pinout & Package
Package: DO-214AA (SMB), surface-mount, matte tin-plated leads, polarity indicated by cathode band. Weight: 0.090 g. Meets UL 94V-0 and JESD201 Class 2 whisker resistance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to ground or return path; forms current loop during clamping event. |
| Cathode | High-side surge input terminal | Connected to protected line (e.g., 12V rail); avalanche conduction occurs from cathode to anode during overvoltage. |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Ensures stable VBR and low leakage over temperature and lifetime; critical for automotive AEC-Q200 alignment. |
| Clamping voltage ≤22.0 V @ 28 A | Provides ≥2.5× margin between VC and typical 12V system rail, preventing downstream IC latch-up or damage. |
| ISO 7637-2 compliance (Pulse 1/2a/2b/3a/3b) | Validates robustness against real-world automotive load-dump and inductive switching transients. |
| Moisture sensitivity level 1 | Eliminates bake requirements before reflow; supports standard SMT assembly without process modification. |
Applications
| Automotive Body Control Module | Industrial PLC I/O Protection |
|---|---|
Use Scenario: Protecting LIN bus and 12V sensor supply lines from load dump and alternator ripple in vehicle door modules. IC Role / Device Role / Timing Role: Unidirectional TVS clamp placed between power rail and ground, absorbing energy before it reaches MCU or transceiver ICs. Use Value: Limits transient voltage to ≤22.0 V, preserving 3.3V/5V logic integrity and meeting OEM EMC test limits per ISO 11452-4. |
Use Scenario: Shielding 24V digital input channels in programmable logic controllers from field-wiring induced surges. IC Role / Device Role / Timing Role: Primary overvoltage suppression element upstream of optocoupler or Schmitt-trigger input stage. Use Value: Withstands 600W pulses without degradation, ensuring >100,000 surge cycles in factory automation environments. |
| LED Driver Power Input | USB-C Power Delivery Line |
Use Scenario: Safeguarding constant-current LED drivers against inductive kickback from relay-controlled dimming circuits. IC Role / Device Role / Timing Role: Fast-clamping TVS on DC input rail, triggered within <1 ps to prevent MOSFET gate oxide failure. Use Value: Clamps 10/1000µs surges to 22.0 V while maintaining <1 µA leakage, avoiding standby current drain in smart lighting systems. |
Use Scenario: Secondary-level surge protection on VBUS line of USB-C receptacles in portable medical monitors. IC Role / Device Role / Timing Role: Standoff protector co-located with ESD array, handling higher-energy events beyond IEC 61000-4-2. Use Value: Provides 600W surge rating and RoHS/halogen-free compliance required for Class II medical device certifications. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ12A | Narrower VBR range (13.3–14.7 V), lower clamping voltage (19.9 V @ 31 A), tighter tolerance. | Better suited for precision 12V rail protection where lower VC improves margin over 3.3V/5V logic. | Select SMBJ12A when clamping voltage headroom is critical and tighter VBR distribution reduces binning needs. |
| SAC12 | Same VWM (12 V), but lower PPK (400 W), higher VC (23.2 V @ 17.4 A), different DO-214AC (SMC) package. | Used in legacy designs with larger footprints; less suitable for space-constrained automotive PCBs. | Choose SAC12 only if existing layout uses SMC pads or lower surge energy (≤400 W) is sufficient. |
Compared with SMBJ12, SMBJ12A offers improved clamping consistency at the cost of slightly reduced surge current capacity, while SAC12 trades power handling and footprint compatibility for broader industry familiarity - making SMBJ12 the balanced choice for new 12V automotive and industrial designs requiring 600W immunity.
Availability
SMBJ12 is available at Aetrix Electronics and suitable for automotive electronics, industrial PLCs, and LED driver designs requiring stable component supply, long-term lifecycle support, and RoHS/halogen-free compliance.
Supply support for SMBJ12 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, specializing in TVS diodes, rectifiers, and power MOSFETs since 1979.
The SMBJ series was developed to deliver high-power, AEC-Q200-aligned transient protection in compact SMB packages for automotive and industrial power systems demanding reliability under harsh thermal and electrical stress.
FAQ
What is the maximum clamping voltage of SMBJ12 under a 10/1000µs surge?
The SMBJ12 has a maximum clamping voltage (VC) of 22.0 V when subjected to a 28 A peak pulse current with a 10/1000 µs waveform. This value is measured per ANSI/IEEE C62.35 and ensures predictable overvoltage limiting for downstream 12V-rated components. The SMBJ12 datasheet specifies this parameter under standard test conditions (TA = 25°C), and derating applies at elevated ambient temperatures.
Is SMBJ12 suitable for bidirectional transient protection?
No - SMBJ12 is a unidirectional TVS diode, intended for DC rail protection with defined polarity (cathode band marks the high-side terminal). For bidirectional applications such as AC lines or data buses, use SMBJ12C or SMBJ12CA, which feature symmetrical breakdown in both directions. The SMBJ12 itself does not conduct in reverse bias beyond its specified leakage and will not clamp negative transients.
What is the marking code printed on the SMBJ12 package?
The SMBJ12 is marked with the code "LD" on its DO-214AA (SMB) package body. This two-character marking appears adjacent to the cathode band and aligns with Taiwan Semiconductor's standardized coding scheme for the SMBJ series. The "LD" identifier is confirmed in the official electrical specifications table and used for visual and automated optical inspection during assembly.
Does SMBJ12 meet automotive qualification standards?
The SMBJ12 meets ISO 7637-2 (Pulse 1/2a/2b/3a/3b) for automotive transient immunity and is constructed with moisture sensitivity level 1 (per J-STD-020), supporting lead-free reflow without baking. While not explicitly AEC-Q200 certified in this documentation, its electrical specs, thermal ratings (–55°C to +150°C), and construction align with common AEC-Q200 stress test requirements for TVS diodes used in body electronics.
What is the thermal resistance from junction to ambient for SMBJ12?
The SMBJ12 has a junction-to-ambient thermal resistance (RθJA) of 55°C/W under standard JEDEC test conditions (on FR-4 board with 1 in² copper pad). This value governs temperature rise during sustained power dissipation and must be applied with derating curves (Fig.2) when ambient exceeds 25°C. For thermal design, RθJC = 10°C/W enables estimation of heatsink interface impact if mounted to metal-core PCBs.
SMBJ12 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:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 12V
- Voltage - Breakdown (Min):
- 13.3V
- Voltage - Clamping (Max) @ Ipp:
- 22V
- Current - Peak Pulse (10/1000µs):
- 28A
- 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)
SMBJ12 FAQ
1.How can I place an order for SMBJ12 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ12 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 SMBJ12 reliable?
The price and inventory of SMBJ12 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ12 is usually 5 days.
3.What payment methods are accepted for SMBJ12?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ12 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ12?
SMBJ12 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ12 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 SMBJ12?
For technical support, including SMBJ12 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ12 requirements.
6.How does Aetrix verify that SMBJ12 is sourced from the original manufacturer or authorized distributors?
All SMBJ12 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 SMBJ12 meets industry standards.
7.What is the process for return or replacement of SMBJ12?
All SMBJ12 units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ12, 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 SMBJ12 part is unused and in its original packaging.
Return procedure for SMBJ12:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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