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Vishay General Semiconductor - Diodes Division SMBJ78AHM3/I
- Part No.:
- SMBJ78AHM3/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ78AHM3/I.pdf
- Description:
- TVS DIODE 78VWM 126VC DO214AA
- Quantity:
- Payment:
- Shipping:
Inventory:3,372
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Product details
Overview
SMBJ78AHM3/I from Vishay General Semiconductor is a unidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMB (DO-214AA) package, designed for clamping voltage transients on power and signal lines. It features a 78 V stand-off voltage (VWM), 86.7–95.8 V breakdown voltage (VBR) at 1 mA, 126 V maximum clamping voltage (VC) at 4.8 A peak pulse current (IPPM), and 600 W peak pulse power (10/1000 µs waveform). It is used to protect MOSFETs, ICs, and sensor signal lines in industrial motor drives and telecom power supplies.
For engineers reviewing the SMBJ78AHM3/I datasheet, SMBJ78AHM3/I pinout, SMBJ78AHM3/I application, or SMBJ78AHM3/I equivalent, this page delivers verified electrical parameters, thermal behavior, AEC-Q101 qualification status, halogen-free RoHS compliance, and real-world protection use cases - all confirmed from Vishay's official SMBJ5.0A–SMBJ188A specification document (Rev. 09-Jan-2024, Doc. #88392).
Technical Context
This TVS diode operates as a unidirectional clamping device with cathode-band polarity marking, optimized for fast transient suppression in DC power rails and low-voltage analog/sensor interfaces. Its glass-passivated junction ensures stable breakdown characteristics, while its 100 °C/W junction-to-ambient thermal resistance requires careful PCB copper pad design per Vishay's recommended 0.2" × 0.2" (5.0 mm × 5.0 mm) pad layout.
The SMBJ78AHM3/I delivers 126 V clamping at 4.8 A under 10/1000 µs surge conditions, with <1 ns response time and 0.01% duty cycle capability. Its 1.0 µA max reverse leakage at 78 V and +150 °C max junction temperature support reliable operation in automotive-grade industrial environments where thermal cycling and long-term reliability are critical.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM (Stand-off Voltage) | 78 V - Maximum continuous reverse voltage before significant leakage; defines operating margin below clamping threshold. |
| VBR (Breakdown Voltage) | 86.7–95.8 V at 1 mA - Confirmed minimum/maximum breakdown range; ensures consistent turn-on across production lots. |
| VC (Clamping Voltage) | 126 V at IPPM = 4.8 A (10/1000 µs) - Peak voltage seen by protected circuit during surge; determines downstream component stress. |
| PPPM (Peak Pulse Power) | 600 W - Sustained energy absorption capability under standardized transient waveform; enables robust ESD and lightning surge immunity. |
| ID (Reverse Leakage) | 1.0 µA max at VWM = 78 V - Low leakage preserves system efficiency and prevents false triggering in high-impedance circuits. |
| TJ max | +150 °C - Maximum junction temperature rating; supports operation in under-hood automotive and enclosed industrial enclosures. |
| Package | SMB (DO-214AA) - Surface-mount outline with 2.20 mm min. cathode band width; compatible with automated pick-and-place and reflow soldering. |
Pinout & Package
Package: SMB (DO-214AA), molded plastic case with matte tin-plated leads, UL 94 V-0 rated compound, MSL Level 1 (260 °C peak reflow).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to ground or lower-potential rail; forms forward-biased path during positive transients on cathode side. |
| Cathode | High-side surge input terminal | Marked with band; connects to protected line (e.g., 78 V supply rail); conducts when voltage exceeds VBR to clamp to VC. |
Key Features
| Feature | Design Value |
|---|---|
| 600 W peak pulse power (10/1000 µs) | Enables single-event suppression of IEC 61000-4-5 Level 3 surges (1 kV/2 Ω) on 78 V DC rails without degradation. |
| AEC-Q101 qualified (HM3 suffix) | Validated for automotive powertrain and body electronics applications requiring zero defect reliability over temperature and lifetime. |
| Halogen-free & RoHS-compliant | Meets EU Directive 2011/65/EU and JEDEC J-STD-20D; eliminates brominated flame retardants for safer end-of-life processing. |
| Low incremental surge resistance | Minimizes voltage overshoot during fast-rising transients (<1 ns response), improving protection fidelity for sensitive analog front-ends. |
| 100 A IFSM (8.3 ms half-sine) | Withstands repetitive inrush currents in power supply input stages, supporting robustness against repeated switching surges. |
Applications
| Industrial Motor Drive Protection | Telecom DC Power Input |
|---|---|
|
Use Scenario: Protecting gate drivers and microcontrollers from inductive kickback during IGBT/MOSFET switching in 72–80 V DC bus systems. IC Role / Device Role / Timing Role: Unidirectional clamping diode placed between DC bus and ground, triggered within nanoseconds to limit voltage spikes to ≤126 V. Use Value: Prevents gate oxide rupture in 100 V-rated MOSFETs and latch-up in 3.3 V logic controllers exposed to >200 V transients. |
Use Scenario: Safeguarding primary-side DC/DC converter inputs in 48 V telecom rectifiers subjected to lightning-induced surges per IEC 61000-4-5. IC Role / Device Role / Timing Role: Standoff-clamp TVS connected across input terminals, absorbing up to 600 W for 1 ms to hold downstream regulator input within safe limits. Use Value: Maintains uninterrupted operation during 4 kV common-mode surges by limiting peak input voltage to 126 V, avoiding brownout or shutdown. |
| Automotive Body Control Module | Industrial Sensor Signal Line |
|
Use Scenario: Protecting LIN bus transceivers and power management ICs in BCMs powered from 12 V battery (with 78 V load-dump tolerance). IC Role / Device Role / Timing Role: Load-dump suppressor on main 12 V supply rail, activated during ISO 7637-2 Pulse 5a (78 V, 400 ms) events. Use Value: Clamps sustained overvoltage to ≤126 V while dissipating 5.0 W continuously, preventing thermal runaway and ensuring ASIL-B functional safety compliance. |
Use Scenario: Shielding 4–20 mA current-loop sensors in factory automation from ESD and cable-coupled noise in 24 V loop-powered systems. IC Role / Device Role / Timing Role: Low-leakage (≤1 µA) unidirectional TVS placed across sensor output terminals to shunt transients before reaching ADC input. Use Value: Preserves measurement accuracy by limiting induced error to <0.1% full-scale due to sub-126 V clamping and negligible standby current draw. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ78AHE3/I | Same electrical specs, but RoHS-compliant commercial grade (not halogen-free or AEC-Q101 qualified). | Lacks automotive qualification and halogen-free certification; suitable only for non-automotive industrial or consumer designs. | Select when AEC-Q101 and halogen-free requirements are not mandated, and cost optimization is prioritized. |
| SMBJ78A-M3/5B | Identical electrical and thermal specs; differs only in packaging (13" reel, 3200 pcs) and base P/N suffix format. | No functional or application difference; same SMB package, same HM3 material classification (halogen-free, RoHS). | Choose based on volume procurement needs and preferred tape-and-reel configuration - no design impact. |
Compared with SMBJ78AHM3/I, SMBJ78AHE3/I omits AEC-Q101 validation and halogen-free assurance, limiting automotive use; SMBJ78A-M3/5B offers identical performance and compliance but in a different reel size - making it a drop-in sourcing alternative without layout or qualification changes.
Availability
SMBJ78AHM3/I is available at Aetrix Electronics and suitable for industrial motor drives, telecom DC power inputs, automotive body control modules, and industrial sensor signal lines requiring stable component supply, long-term lifecycle support, and traceable halogen-free sourcing.
Supply support for SMBJ78AHM3/I 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
Vishay General Semiconductor is a global leader in discrete semiconductors, specializing in diodes, rectifiers, MOSFETs, and protection devices with emphasis on reliability, power efficiency, and automotive-grade qualification.
The SMBJ series is engineered for high-energy transient suppression in harsh environments, targeting automotive, industrial, and telecom applications where robustness against ESD, lightning, and inductive switching surges is mandatory.
FAQ
What is the clamping voltage of SMBJ78AHM3/I at its rated peak pulse current?
The SMBJ78AHM3/I has a maximum clamping voltage (VC) of 126 V when subjected to its specified peak pulse current (IPPM) of 4.8 A under the standard 10/1000 µs waveform. This value is measured per Vishay's test conditions in Document #88392 and defines the upper voltage limit imposed on protected circuitry during surge events. The SMBJ78AHM3/I maintains this clamping performance across its operational temperature range and after repeated surges within its duty cycle limit.
Is SMBJ78AHM3/I qualified for automotive applications?
Yes, SMBJ78AHM3/I is AEC-Q101 qualified, as indicated by the "HM3" suffix in its part number - confirming compliance with stress tests for temperature cycling, humidity, mechanical shock, and surge robustness required for automotive electronics. This qualification applies specifically to the HM3 variant and supports use in body control modules, infotainment power supplies, and other non-safety-critical automotive subsystems where transient immunity is essential.
What does the "HM3" suffix mean in SMBJ78AHM3/I?
The "HM3" suffix in SMBJ78AHM3/I denotes halogen-free, RoHS-compliant, and AEC-Q101-qualified construction. It distinguishes this variant from commercial-grade versions (e.g., E3) and confirms adherence to automotive reliability standards, absence of brominated flame retardants, and full regulatory compliance for both industrial and automotive deployments. The "I" denotes 13-inch tape-and-reel packaging with 3200 units per reel.
How does SMBJ78AHM3/I differ from bidirectional TVS diodes like SMBJ78CA?
SMBJ78AHM3/I is unidirectional and functions only during reverse-bias overvoltage events, with polarity-sensitive mounting (cathode band toward the protected line). In contrast, SMBJ78CA is bidirectional and protects against surges of either polarity, with no polarity marking. The SMBJ78AHM3/I offers lower leakage (1.0 µA vs. up to 2.0 µA for CA types at same VWM) and is preferred for DC rail protection where polarity is fixed and leakage sensitivity matters.
What PCB layout guidance applies to SMBJ78AHM3/I for optimal thermal performance?
Vishay specifies a minimum 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pad area per terminal for SMBJ78AHM3/I to achieve its rated 600 W pulse power and manage thermal dissipation. Smaller pads increase junction temperature, derating both peak power and reliability. The SMB (DO-214AA) package's RθJA of 100 °C/W assumes this layout; reducing pad size or omitting thermal vias may raise TJ beyond +150 °C during surge events, risking parametric shift or failure.
SMBJ78AHM3/I Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AA, SMB
- Series:
- TransZorb®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 78V
- Voltage - Breakdown (Min):
- 86.7V
- Voltage - Clamping (Max) @ Ipp:
- 126V
- Current - Peak Pulse (10/1000µs):
- 4.8A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- Telecom
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AA (SMB)
SMBJ78AHM3/I FAQ
1.How can I place an order for SMBJ78AHM3/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ78AHM3/I 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 SMBJ78AHM3/I reliable?
The price and inventory of SMBJ78AHM3/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ78AHM3/I is usually 5 days.
3.What payment methods are accepted for SMBJ78AHM3/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ78AHM3/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ78AHM3/I?
SMBJ78AHM3/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ78AHM3/I 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 SMBJ78AHM3/I?
For technical support, including SMBJ78AHM3/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ78AHM3/I requirements.
6.How does Aetrix verify that SMBJ78AHM3/I is sourced from the original manufacturer or authorized distributors?
All SMBJ78AHM3/I 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 SMBJ78AHM3/I meets industry standards.
7.What is the process for return or replacement of SMBJ78AHM3/I?
All SMBJ78AHM3/I units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ78AHM3/I, 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 SMBJ78AHM3/I part is unused and in its original packaging.
Return procedure for SMBJ78AHM3/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ78AHM3/I Tags
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DESD3V3E1BL-7B
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Toshiba Semiconductor and Storage
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Diodes Incorporated
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