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Taiwan Semiconductor Corporation SMBJ78H
- Part No.:
- SMBJ78H
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ78H.pdf
- Description:
- 600W, 96.4V, 10%, UNIDIRECTIONAL
- Quantity:
- Payment:
- Shipping:
Inventory:4,924
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Product details
Overview
SMBJ78H from Taiwan Semiconductor is a unidirectional 600W surface-mount transient voltage suppressor (TVS) diode in DO-214AA (SMB) package, with 78 V working stand-off voltage (VWM), 86.7–106 V breakdown voltage (VBR), and 139 V maximum clamping voltage (VC) at 4.5 A peak impulse current - designed for automotive-grade ESD and load-dump protection in power supply rails and signal lines.
For engineers reviewing the SMBJ78H datasheet, SMBJ78H pinout, SMBJ78H application, or SMBJ78H equivalent, key selection criteria include clamping performance under ISO 7637-2 Pulse 1/2a/2b/3a/3b, AEC-Q101 qualification, junction temperature range (−55°C to +150°C), and compatibility with automated SMT assembly on 1.5 mm pitch PCBs.
Technical Context
The SMBJ78H operates as a unidirectional avalanche diode, triggered when reverse voltage exceeds its specified VBR (86.7–106 V @ 1 mA). It delivers sub-1 ps response time and clamps transients to ≤139 V at 4.5 A (10/1000 µs waveform), limiting energy dissipation to 600 W non-repetitive peak pulse power.
Thermal design relies on RθJC = 10°C/W and RθJA = 55°C/W, enabling operation up to TJ = 150°C. Its glass-passivated junction and matte tin-plated leads meet J-STD-002 solderability and JESD 201 Class 2 whisker resistance requirements.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 78 V - Maximum continuous reverse operating voltage before clamping initiates |
| VBR min/max | 86.7 V / 106 V @ 1 mA - Ensures reliable turn-on margin above VWM with production tolerance |
| VC @ IPP | 139 V @ 4.5 A (10/1000 µs) - Defines worst-case voltage seen by protected IC during surge |
| PPK | 600 W - Peak transient power handling capability per single event |
| ID @ VWM | ≤1 µA - Low leakage preserves system standby current in battery-powered applications |
| TJ max | +150 °C - Supports under-hood automotive environments and high-power board layouts |
| Package | DO-214AA (SMB) - Standardized 3.5 mm × 4.5 mm footprint compatible with IPC-7351B land patterns |
Pinout & Package
DO-214AA (SMB) package: molded plastic case with cathode band marking; terminals are matte tin-plated leads suitable for reflow soldering per J-STD-002; polarity is unidirectional with cathode indicated by band.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Ground reference terminal | Connected to system ground or low-side return path; carries full surge current during clamping |
| Cathode | Protected line input | Connected to line being protected (e.g., 12 V rail); reverse-biased during normal operation |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive electronics per stress test requirements including HTOL, TC, UHAST, and ESD-HBM/MM |
| Glass passivated junction | Enhances long-term reliability and moisture resistance vs. epoxy-passivated alternatives |
| ISO 7637-2 compliance | Meets Pulse 1 (inductive load dump), Pulse 2a/2b (switching transients), and Pulse 3a/3b (capacitive coupling) immunity requirements |
| Fast response time | <1.0 ps - Enables suppression of ESD events before sensitive ICs experience damage |
| Moisture sensitivity level 1 | No floor life limitation; safe for standard SMT assembly without baking prior to reflow |
Applications
| Automotive Power Rail Protection | Industrial Sensor Interface Protection |
|---|---|
Use Scenario: 12 V/24 V battery-fed ECUs exposed to load dump and jump-start surges per ISO 7637-2. IC Role / Device Role / Timing Role: Unidirectional TVS placed between power input and ground to clamp transients before DC-DC converters or microcontrollers. Use Value: Limits voltage to ≤139 V during 4.5 A surge, preventing latch-up or gate oxide rupture in downstream 3.3 V/5 V logic. | Use Scenario: Analog sensor outputs (e.g., pressure, temperature) routed across noisy industrial enclosures. IC Role / Device Role / Timing Role: TVS mounted at connector entry point to shunt EFT bursts (IEC 61000-4-4) and contact ESD (IEC 61000-4-2). Use Value: Sub-1 ps response ensures clamping occurs before 15 kV ESD pulse couples into signal conditioning op-amps. |
| LED Lighting Driver Protection | Automotive CAN Bus Line Protection |
Use Scenario: Constant-current LED drivers subjected to inductive switching transients from relay or solenoid control. IC Role / Device Role / Timing Role: TVS placed across driver output to absorb flyback energy from inductive loads. Use Value: 600 W peak power rating handles repetitive 10/1000 µs pulses without thermal runaway or parameter shift. | Use Scenario: CAN H/L lines in body control modules exposed to coupled transients from adjacent high-current wiring. IC Role / Device Role / Timing Role: Bidirectional protection not applicable here; SMBJ78H used only on power-supply side feeding CAN transceiver. Use Value: 78 V VWM allows use on 60 V-rated CAN power rails while maintaining ≥8.7 V margin to VBR min. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ78A | VBR tighter: 86.7–95.8 V (vs. 86.7–106 V); lower VC = 126 V @ 5.0 A | Better clamping for precision analog rails where <130 V ceiling is required | Select SMBJ78A if system-level testing shows 126 V clamping improves margin over 139 V |
| SMCJ78H | Same VWM/VBR/VC specs but in larger DO-214AB (SMC) package; PPK = 1500 W | Used where higher surge endurance or thermal mass is needed (e.g., alternator output) | Choose SMCJ78H only if layout allows 7.1 mm × 6.2 mm footprint and 1500 W rating is required |
Compared with SMBJ78A, the SMBJ78H offers wider VBR tolerance and higher clamping voltage, trading precision for robustness in high-energy transients; versus SMCJ78H, it sacrifices surge capacity and thermal mass for space-constrained SMT layouts.
Availability
SMBJ78H is available at Aetrix Electronics and suitable for automotive ECUs, industrial sensor interfaces, LED lighting drivers, and CAN bus power rail protection requiring stable component supply across extended temperature and surge conditions.
Supply support for SMBJ78H 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, with global distribution and AEC-Q101 validation capabilities.
The SMBJH series was developed specifically for automotive and industrial transient suppression, emphasizing AEC-Q101 qualification, ISO 7637-2 compliance, and surface-mount reliability in harsh environments.
FAQ
What is the maximum clamping voltage of SMBJ78H under standard test conditions?
The SMBJ78H has a maximum clamping voltage (VC) of 139 V when subjected to a 10/1000 µs surge current of 4.5 A. This value is measured at TA = 25°C and defines the upper voltage limit imposed on protected circuitry during transient events. The SMBJ78H maintains this clamping performance across its full operating junction temperature range.
Is SMBJ78H suitable for bidirectional transient protection?
No, SMBJ78H is a unidirectional TVS diode intended for DC power line protection where polarity is fixed. For bidirectional applications such as AC lines or data bus protection, the SMBJ78CH or SMBJ78AH variants must be used. The SMBJ78H cathode band marking indicates polarity and must be oriented correctly in-circuit to avoid forward conduction during normal operation.
Does SMBJ78H meet automotive qualification standards?
Yes, SMBJ78H is AEC-Q101 qualified and meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b test requirements. It is rated for junction temperatures from −55°C to +150°C and features glass passivation, JESD 201 Class 2 whisker resistance, and moisture sensitivity level 1 - all critical for under-hood and chassis-mounted automotive electronics.
What is the leakage current specification for SMBJ78H at its working voltage?
At its 78 V working stand-off voltage (VWM), the SMBJ78H exhibits a maximum blocking leakage current (ID) of 1 µA at TA = 25°C. This low leakage supports energy-efficient designs, especially in always-on automotive modules where cumulative standby current must remain below microamp thresholds to prevent battery drain.
What package type and dimensions does SMBJ78H use?
SMBJ78H uses the DO-214AA (SMB) surface-mount package, measuring 3.5 mm × 4.5 mm × 2.3 mm with 1.5 mm lead pitch. Its standardized footprint aligns with IPC-7351B recommendations, and the cathode band provides unambiguous polarity identification for automated optical inspection and placement verification during SMT assembly.
SMBJ78H 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):
- 78V
- Voltage - Breakdown (Min):
- 86.7V
- Voltage - Clamping (Max) @ Ipp:
- 139V
- Current - Peak Pulse (10/1000µs):
- 4.5A
- 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)
SMBJ78H FAQ
1.How can I place an order for SMBJ78H through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ78H 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 SMBJ78H reliable?
The price and inventory of SMBJ78H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ78H is usually 5 days.
3.What payment methods are accepted for SMBJ78H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ78H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ78H?
SMBJ78H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ78H 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 SMBJ78H?
For technical support, including SMBJ78H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ78H requirements.
6.How does Aetrix verify that SMBJ78H is sourced from the original manufacturer or authorized distributors?
All SMBJ78H 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 SMBJ78H meets industry standards.
7.What is the process for return or replacement of SMBJ78H?
All SMBJ78H units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ78H, 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 SMBJ78H part is unused and in its original packaging.
Return procedure for SMBJ78H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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