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Taiwan Semiconductor Corporation SMBJ28H
- Part No.:
- SMBJ28H
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ28H.pdf
- Description:
- 600W, 34.6V, 10%, UNIDIRECTIONAL
- Quantity:
- Payment:
- Shipping:
Inventory:7,473
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Product details
Overview
SMBJ28H from Taiwan Semiconductor is a unidirectional 600W surface-mount transient voltage suppressor (TVS) diode in DO-214AA (SMB) package, with 28 V working stand-off voltage (VWM), 31.1–38.0 V breakdown voltage (VBR), and 50.0 V maximum clamping voltage (VC) at 12.6 A peak pulse current. It delivers fast response (<1.0 ps), low leakage (<1 µA @ 28 V), and AEC-Q101 qualification for automotive power rail protection.
For engineers reviewing the SMBJ28H datasheet, SMBJ28H pinout, SMBJ28H application, or SMBJ28H equivalent, key selection criteria include clamping performance under ISO 7637-2 Pulse 1/2a/2b/3a/3b transients, thermal resistance (RθJA = 55 °C/W), unidirectional polarity marking, and compatibility with automated SMT placement on 12 V–24 V DC systems.
Technical Context
The SMBJ28H operates as a unidirectional avalanche diode, triggered when reverse voltage exceeds its specified VBR range (31.1–38.0 V @ 1 mA). Its glass-passivated junction ensures stable breakdown behavior and low leakage (<1 µA @ VWM = 28 V), while the DO-214AA package supports high surge handling (600 W, 10/1000 µs waveform) with RθJC = 10 °C/W.
Designed for automotive-grade reliability, it meets AEC-Q101 stress testing and ISO 7637-2 immunity requirements for load dump and inductive switching transients. Its 150 °C max junction temperature and J-STD-020 Level 1 moisture sensitivity rating enable robust reflow compatibility and long-term operation in engine control units and body electronics.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 28 V - Maximum continuous reverse operating voltage before conduction begins; sets system overvoltage trip threshold for 24 V nominal rails. |
| VBR @ IT=1 mA | 31.1–38.0 V - Breakdown voltage range defining minimum and maximum avalanche onset; ensures consistent clamping across production lot. |
| VC @ IPP=12.6 A | 50.0 V - Clamped voltage during 10/1000 µs surge; limits downstream IC stress to safe margin below 55 V absolute max ratings. |
| PPK | 600 W - Peak pulse power dissipation capability; sustains single-event transients up to 12.6 A without failure. |
| ID @ VWM | <1 µA - Reverse leakage at rated stand-off; minimizes quiescent power loss and avoids false triggering in low-power sensor circuits. |
| RθJA | 55 °C/W - Junction-to-ambient thermal resistance; enables ~10.9 °C rise at 3 W steady-state dissipation in standard PCB layout. |
Pinout & Package
DO-214AA (SMB) surface-mount package with cathode band marking for unidirectional polarity. Matte tin-plated leads meet J-STD-002 solderability; case complies with UL 94V-0 flammability rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward current path / low-side reference | Connected to ground or low-voltage return; defines reference point for clamping action during positive transients on cathode side. |
| Cathode | Transient voltage input / protected line | Connected to supply rail (e.g., 24 V battery line); conducts avalanche current to anode when voltage exceeds VBR. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive underhood environments including temperature cycling, humidity bias, and mechanical shock per AEC stress test plan. |
| Glass passivated junction | Ensures stable VBR tolerance and low leakage drift over time and temperature-critical for long-life ECU designs. |
| Clamping voltage ≤50.0 V @ 12.6 A | Provides defined overvoltage ceiling for 24 V systems, protecting downstream CAN transceivers, microcontrollers, and analog front-ends. |
| ISO 7637-2 compliant (Pulse 1/2a/2b/3a/3b) | Guarantees immunity to real-world automotive transients including load dump, alternator ripple, and inductive switch-off spikes. |
Applications
| Automotive Power Rail Protection | Industrial Sensor Interface Protection |
|---|---|
Use Scenario: Installed across 24 V battery feed to engine control unit (ECU) to suppress load dump and alternator-induced surges. IC Role / Device Role / Timing Role: Unidirectional TVS diode clamping transient energy to ground during ISO 7637-2 Pulse 5a events. Use Value: Limits peak voltage seen by MCU power pins to ≤50.0 V, preventing latch-up or oxide damage in 3.3 V/5 V logic domains. | Use Scenario: Placed on 24 V supply line of industrial pressure sensor module exposed to relay-coil switching noise. IC Role / Device Role / Timing Role: Fast-response (≤1 ps) voltage clamp absorbing inductive kickback from nearby solenoid drivers. Use Value: Maintains sensor accuracy by preventing >1 µA leakage-induced offset drift and avoiding false resets during EFT bursts. |
| LED Lighting Driver Input Protection | Automotive Body Control Module (BCM) |
Use Scenario: Mounted at input stage of constant-current LED driver board in commercial vehicle lighting system. IC Role / Device Role / Timing Role: Standby-mode protector absorbing repetitive 10/1000 µs transients from shared chassis ground bounce. Use Value: Enables 600 W surge rating with <1 µA leakage at 28 V, eliminating standby power penalty while sustaining >100,000 surge cycles. | Use Scenario: Integrated into door module PCB to protect LIN transceiver and window motor driver ICs from ESD and cable discharge. IC Role / Device Role / Timing Role: Primary overvoltage guard on 12 V supply rail, responding within picoseconds to human-body-model (HBM) and IEC 61000-4-2 events. Use Value: Meets AEC-Q101 and J-STD-020 Level 1, enabling direct reflow assembly without moisture bake-out delays. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ28A | Narrower VBR range (31.1–34.4 V vs. 31.1–38.0 V); lower VC = 45.4 V @ 13.8 A | Better clamping margin for sensitive 3.3 V logic interfaces; tighter VBR tolerance suits precision voltage thresholding. | Select SMBJ28A when lower clamping voltage and tighter breakdown spec are required; verify IPP derating for same surge energy. |
| SAC28 | Same VWM/VBR specs but in smaller SOD-123FL package; PPK = 400 W (vs. 600 W) | Space-constrained consumer modules where 600 W headroom is unnecessary; not AEC-Q101 qualified. | Choose SAC28 only for non-automotive, low-surge environments; SMBJ28H remains preferred for ISO 7637-2 compliance and thermal robustness. |
Compared with SMBJ28A and SAC28, the SMBJ28H offers the highest surge power rating (600 W), full AEC-Q101 qualification, and verified ISO 7637-2 immunity-making it the default choice for automotive 24 V rail protection where reliability and transient headroom are critical.
Availability
SMBJ28H is available at Aetrix Electronics and suitable for automotive power rail protection, industrial sensor interface protection, and LED lighting driver input protection requiring stable component supply, AEC-Q101 traceability, and ISO 7637-2 compliance.
Supply support for SMBJ28H 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 Taiwanese semiconductor manufacturer specializing in discrete power devices, TVS diodes, rectifiers, and MOSFETs for automotive, industrial, and computing markets.
The SMBJH series was developed specifically for AEC-Q101-compliant transient suppression in 12 V–170 V automotive power systems, emphasizing robust clamping, low leakage, and high-reliability packaging for under-hood deployment.
FAQ
What is the maximum clamping voltage of SMBJ28H at its rated peak pulse current?
The SMBJ28H has a maximum clamping voltage (VC) of 50.0 V when subjected to its rated peak pulse current of 12.6 A using the standard 10/1000 µs waveform. This value is measured per ANSI/IEEE C62.35 and guarantees that downstream components connected to the protected 24 V rail will not experience voltages exceeding 50.0 V during transient events. The SMBJ28H maintains this clamping performance across its full operating temperature range.
Is SMBJ28H suitable for bidirectional transient protection?
No, SMBJ28H is a unidirectional TVS diode intended for DC supply line protection with defined polarity (cathode to line, anode to ground). For bidirectional applications such as AC lines or data bus protection, the SMBJ28CH or SMBJ28AH variants must be used instead. The SMBJ28H datasheet explicitly states electrical characteristics apply only in the reverse direction, and its cathode band marking confirms unidirectional orientation.
Does SMBJ28H meet automotive qualification standards?
Yes, SMBJ28H is AEC-Q101 qualified and meets ISO 7637-2 immunity requirements for Pulse 1, 2a, 2b, 3a, and 3b transients. It also complies with J-STD-020 moisture sensitivity Level 1, JESD 201 Class 2 whisker resistance, and RoHS/halogen-free standards per IEC 61249-2-21. These qualifications are documented in Taiwan Semiconductor's official SMBJH Series datasheet Version A2102.
What is the thermal resistance from junction to ambient for SMBJ28H?
The SMBJ28H has a junction-to-ambient thermal resistance (RθJA) of 55 °C/W under standard JEDEC test conditions (single device on 1 in² copper pad). This value allows estimation of junction temperature rise during sustained power dissipation-for example, at 3 W steady-state power (its PD rating), the junction rises ~165 °C above ambient, confirming its suitability only for transient, not continuous, power handling. RθJC is 10 °C/W for heatsink-coupled designs.
How does SMBJ28H differ from SMBJ28AH in terms of breakdown voltage?
The SMBJ28H has a breakdown voltage (VBR) range of 31.1–38.0 V at 1 mA test current, while the SMBJ28AH variant has a tighter range of 31.1–34.4 V. This narrower specification makes SMBJ28AH preferable where precise clamping onset is required, such as in systems with narrow voltage margins between VWM and downstream IC absolute maximum ratings. Both share identical VWM (28 V), package (DO-214AA), and AEC-Q101 qualification.
SMBJ28H Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- DO-214AA, SMB
- Series:
- SMBJH
- 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:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AA (SMB)
SMBJ28H FAQ
1.How can I place an order for SMBJ28H through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ28H 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 SMBJ28H reliable?
The price and inventory of SMBJ28H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ28H is usually 5 days.
3.What payment methods are accepted for SMBJ28H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ28H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ28H?
SMBJ28H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ28H 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 SMBJ28H?
For technical support, including SMBJ28H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ28H requirements.
6.How does Aetrix verify that SMBJ28H is sourced from the original manufacturer or authorized distributors?
All SMBJ28H 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 SMBJ28H meets industry standards.
7.What is the process for return or replacement of SMBJ28H?
All SMBJ28H units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ28H, 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 SMBJ28H part is unused and in its original packaging.
Return procedure for SMBJ28H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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