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Taiwan Semiconductor Corporation SMBJ28
- Part No.:
- SMBJ28
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ28.pdf
- Description:
- 600W, 34.6V, 10%, UNIDIRECTIONAL
- Quantity:
- Payment:
- Shipping:
Inventory:7,035
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Product details
Overview
SMBJ28 from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in DO-214AA (SMB) package, rated for 600W peak pulse power, 28V working stand-off voltage, and 50.0V maximum clamping voltage at 12.6A peak impulse current; used for ESD and surge protection in automotive power line interfaces.
For engineers reviewing the SMBJ28 datasheet, SMBJ28 pinout, SMBJ28 application, or SMBJ28 equivalent, key selection criteria include clamping voltage margin relative to protected IC VDD, leakage current at operating bias, thermal derating above 25°C, and compliance with ISO 7637-2 Pulse 1/2a/2b/3a/3b waveforms.
Technical Context
The SMBJ28 operates as a unidirectional avalanche diode, triggering when reverse voltage exceeds its 31.1–38.0V breakdown range at 1mA test current. It clamps transients to ≤50.0V within <1.0ps response time while maintaining <1μA leakage at 28V DC bias.
Designed for 10/1000μs surge waveform immunity, it delivers 600W non-repetitive peak power dissipation with junction-to-ambient thermal resistance of 55°C/W and maximum junction temperature of +150°C - enabling robust operation in automotive and industrial environments with ambient temperatures up to +125°C after derating.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 28 V - Maximum continuous reverse operating voltage before conduction begins |
| VBR @ IT=1mA | 31.1–38.0 V - Breakdown voltage range defining turn-on threshold under standardized test conditions |
| VC @ IPP=12.6A | 50.0 V - Clamped voltage during 10/1000μs surge, limiting stress on downstream circuitry |
| IPP | 12.6 A - Peak impulse current capability at rated clamping voltage |
| PPK | 600 W - Non-repetitive peak pulse power handling per ISO 7637-2 compliant transients |
| ID @ VWM | <1 μA - Low leakage ensures minimal power loss and signal integrity in standby mode |
| TJ max | +150 °C - Enables reliable operation in under-hood automotive and high-temperature industrial PCB layouts |
Pinout & Package
DO-214AA (SMB) surface-mount package with cathode band marking; matte tin-plated leads, moisture sensitivity level 1 per J-STD-020, UL 94V-0 molding compound.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward current path / low-side connection | Connected to ground or low-voltage rail in unidirectional TVS configuration |
| Cathode | Reverse-biased terminal / protected line input | Connected to signal/power line requiring transient suppression; polarity-marked band identifies this terminal |
Key Features
| Feature | Design Value |
|---|---|
| Glass passivated junction | Ensures stable breakdown voltage and long-term reliability under repeated surge stress |
| Fast response time <1.0 ps | Clamps ESD events before sensitive logic or analog circuitry sustains damage |
| Meets ISO 7637-2 Pulse 1/2a/2b/3a/3b | Validated for automotive load-dump and inductive-switching transient immunity requirements |
| RoHS and halogen-free compliance | Supports environmentally regulated industrial and automotive supply chains per IEC 61249-2-21 |
Applications
| Automotive Power Line Protection | Industrial Sensor Interface Protection |
|---|---|
Use Scenario: Protecting LIN bus transceivers and microcontroller I/O pins from battery line transients during load dump or jump-start events. IC Role / Device Role: Unidirectional TVS placed between VBAT and GND, shunting surges before they reach the protected IC. Use Value: Limits clamped voltage to 50.0V, staying below typical 5.5V or 3.6V IC absolute maximum ratings with safety margin. | Use Scenario: Safeguarding 4–20mA current loop receivers and analog front-end amplifiers from EFT bursts in factory automation systems. IC Role / Device Role: TVS connected across input terminals to absorb fast-rising electrical fast transients (IEC 61000-4-4). Use Value: Sub-1ps response and <1μA leakage preserve signal fidelity and minimize offset error in precision measurement paths. |
| LED Driver Output Protection | DC-DC Converter Input Stage |
Use Scenario: Shielding constant-current LED driver outputs from inductive kickback when driving solenoids or relays in smart lighting modules. IC Role / Device Role: TVS placed across driver output to clamp reverse voltage spikes generated by inductive loads. Use Value: 600W peak power rating handles repetitive switching surges without degradation, extending system lifetime. | Use Scenario: Guarding buck converter input stages against voltage spikes induced by long PCB traces or shared power rails in embedded power supplies. IC Role / Device Role: TVS installed at converter input to limit transient overvoltage before it reaches controller IC and MOSFET gate drivers. Use Value: 28V VWM allows use with 24V nominal systems while providing 22V headroom to VBR min (31.1V), ensuring stable standby operation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ28A | Narrower VBR range (31.1–34.4V vs. 31.1–38.0V); lower clamping voltage (45.4V vs. 50.0V) at same IPP | Better suited for tighter clamping margin requirements where VBR consistency is critical | Select SMBJ28A when lower VC and tighter VBR tolerance improve system-level surge margin |
| SMCJ28 | Larger DO-214AB (SMC) package; higher PPK = 1500W; same VWM/VBR/VC specs but different thermal performance (RθJA = 35°C/W) | Used where higher surge energy absorption or improved thermal dissipation is required | Choose SMCJ28 only if board layout accommodates larger footprint and higher power handling is needed |
Compared with SMBJ28A and SMCJ28, the SMBJ28 offers balanced clamping performance and compact SMB packaging ideal for space-constrained 24V automotive and industrial control boards - whereas SMBJ28A improves voltage tightness and SMCJ28 increases surge capacity at the cost of size.
Availability
SMBJ28 is available at Aetrix Electronics and suitable for automotive infotainment power conditioning, industrial sensor interface protection, and LED driver output safeguarding requiring stable component supply across production lifecycles.
Supply support for SMBJ28 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 semiconductor manufacturer specializing in discrete power devices, TVS diodes, rectifiers, and MOSFETs for automotive, industrial, and consumer markets.
The SMBJ series was developed specifically for surface-mount surge protection in space-constrained, high-reliability applications demanding ISO 7637-2 compliance and low-leakage performance in DO-214AA packaging.
FAQ
What is the maximum clamping voltage of SMBJ28 under standard 10/1000μs surge conditions?
The SMBJ28 has a maximum clamping voltage (VC) of 50.0 V when subjected to a 10/1000μs waveform at its rated peak impulse current of 12.6 A. This value is measured per ANSI/IEEE C62.35 and ensures downstream ICs remain within safe operating voltage limits during transient events. The SMBJ28 maintains this clamping performance across its specified junction temperature range.
Is SMBJ28 unidirectional or bidirectional, and how is polarity identified?
The SMBJ28 is a unidirectional TVS diode, intended for DC line protection where polarity is fixed. Polarity is identified by a cathode band marked on the DO-214AA (SMB) package body - the banded end connects to the protected line (e.g., VBAT), while the anode connects to ground. Bidirectional variants use "C" or "CA" suffixes (e.g., SMBJ28C), which SMBJ28 does not carry.
What is the leakage current specification for SMBJ28 at its working stand-off voltage?
At its 28 V working stand-off voltage (VWM), the SMBJ28 exhibits a maximum blocking leakage current (ID) of 1 μA at TA = 25°C. This ultra-low leakage preserves power efficiency in always-on circuits and avoids false triggering in high-impedance sensing nodes. The SMBJ28 meets this spec across its full operating temperature range per manufacturer characterization.
Does SMBJ28 comply with automotive transient immunity standards?
Yes, the SMBJ28 meets ISO 7637-2 requirements for Pulse 1 (inductive load disconnect), Pulse 2a (sudden load removal), Pulse 2b (supply interruption), Pulse 3a (capacitive coupled EFT), and Pulse 3b (power line EFT). Its 600W peak pulse rating and sub-1ps response time were validated against these waveforms, making SMBJ28 suitable for 12V/24V automotive subsystems including body control modules and lighting drivers.
What is the thermal resistance profile of SMBJ28, and how does it affect PCB layout?
The SMBJ28 has a junction-to-ambient thermal resistance (RθJA) of 55°C/W and junction-to-case (RθJC) of 10°C/W. These values assume standard JEDEC 2-layer board mounting. To maintain TJ ≤ 150°C under repeated surges, PCB layout must provide adequate copper area (≥ 25 mm² per pad) and avoid thermal isolation - especially critical in enclosed automotive enclosures where ambient can exceed 105°C. The SMBJ28's DO-214AA footprint supports automated placement without compromising thermal performance.
SMBJ28 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):
- 28V
- Voltage - Breakdown (Min):
- 31.1V
- Voltage - Clamping (Max) @ Ipp:
- 50V
- Current - Peak Pulse (10/1000µs):
- 12.6A
- 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)
SMBJ28 FAQ
1.How can I place an order for SMBJ28 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ28 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 SMBJ28 reliable?
The price and inventory of SMBJ28 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ28 is usually 5 days.
3.What payment methods are accepted for SMBJ28?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ28 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ28?
SMBJ28 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ28 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 SMBJ28?
For technical support, including SMBJ28 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ28 requirements.
6.How does Aetrix verify that SMBJ28 is sourced from the original manufacturer or authorized distributors?
All SMBJ28 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 SMBJ28 meets industry standards.
7.What is the process for return or replacement of SMBJ28?
All SMBJ28 units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ28, 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 SMBJ28 part is unused and in its original packaging.
Return procedure for SMBJ28:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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