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Vishay General Semiconductor - Diodes Division SMBJ78D-M3/H
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- Part No.:
- SMBJ78D-M3/H
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ78D-M3/H.pdf
- Description:
- TVS DIODE 78VWM 124VC DO214AA
- Quantity:
- Payment:
- Shipping:
Inventory:1,043
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Product details
Overview
SMBJ78D-M3/H from Vishay General Semiconductor is a unidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMB (DO-214AA) package, designed for robust overvoltage protection of DC power rails and signal lines. It features a 78 V stand-off voltage (VWM), 88.1–94.4 V breakdown voltage (VBR) at 1 mA, 124 V maximum clamping voltage (VC) at 4.86 A peak pulse current, and 600 W peak pulse power rating with 10/1000 μs waveform.
For engineers reviewing the SMBJ78D-M3/H datasheet, SMBJ78D-M3/H pinout, SMBJ78D-M3/H application, or SMBJ78D-M3/H equivalent, this device is selected for high-reliability transient suppression in industrial power supplies, automotive ECUs, telecom interface circuits, and sensor front-ends where precise voltage clamping and low leakage (<0.5 μA at VWM) are critical.
Technical Context
This TVS diode operates as a unidirectional avalanche clamp, activated when reverse voltage exceeds its specified VBR range. Its low incremental surge resistance ensures minimal voltage overshoot during fast transients, while the ±3.5 % VBR tolerance enables tight design margins in safety-critical protection paths.
Thermal performance is defined by RθJA = 125 °C/W on minimum pad layout and TJ max = 150 °C, supporting operation in ambient temperatures up to 125 °C after derating. The M3 suffix confirms halogen-free, RoHS-compliant construction with JESD 201 Class 2 whisker resistance and UL 94 V-0 molding compound.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 78 V - Maximum continuous reverse operating voltage before significant conduction begins |
| VBR min/max | 88.1 V / 94.4 V at IT = 1 mA - Tight ±3.5 % tolerance ensures predictable turn-on across production lots |
| VC @ IPPM | 124 V at 4.86 A - Clamped voltage during 10/1000 μs surge defines worst-case stress on downstream components |
| PPPM | 600 W - Peak transient energy handling capability under standardized 10/1000 μs waveform |
| ID @ VWM | ≤0.5 μA - Ultra-low leakage preserves efficiency in high-impedance bias or sensing circuits |
| TJ max | 150 °C - Maximum junction temperature enabling use in under-hood or enclosed industrial environments |
| Package | SMB (DO-214AA) - Standardized surface-mount outline with 2.20 mm height and 5.59 mm length for automated assembly |
Pinout & Package
Package: SMB (DO-214AA), molded plastic case with matte tin-plated leads; polarity indicated by cathode band on the marked end.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to ground or lowest potential node in unidirectional clamp configuration |
| Cathode | High-side surge input terminal | Connected to protected line (e.g., +12 V rail); cathode band identifies this pin on the package |
Key Features
| Feature | Design Value |
|---|---|
| ±3.5 % VBR tolerance | Enables consistent clamping behavior across batches without system-level revalidation |
| 600 W PPPM (10/1000 μs) | Handles IEC 61000-4-5 Level 4 surges (4 kV line-to-ground) with margin in compact SMB footprint |
| MSL Level 1 (260 °C peak) | Supports standard lead-free reflow profiles without moisture-related popcorning or delamination |
| UL 94 V-0 molding compound | Meets flammability requirements for enclosed industrial and telecom equipment enclosures |
| Halogen-free & RoHS-compliant (M3) | Fulfills environmental compliance mandates for global OEM shipments and WEEE recycling |
Applications
| Industrial Power Supply Protection | Automotive Body Control Module (BCM) |
|---|---|
Use Scenario: Protecting 24 V DC input rails in programmable logic controllers (PLCs) against load dump and inductive switching transients. IC Role / Device Role / Timing Role: Unidirectional TVS clamp placed between input rail and chassis ground to shunt surge energy before it reaches DC-DC converters and microcontrollers. Use Value: 124 V clamping voltage limits stress on 36 V-rated input capacitors and 40 V MOSFETs, preserving long-term reliability under repeated 100 V/500 ms load dump events. |
Use Scenario: Safeguarding LIN bus transceivers and sensor inputs in BCMs exposed to battery voltage spikes during alternator regulation faults. IC Role / Device Role / Timing Role: Standoff-clamp element on 12 V supply line feeding LIN PHY ICs, activated only during >78 V excursions. Use Value: Sub-0.5 μA leakage avoids loading sensitive 12 V bias networks, while 600 W rating withstands ISO 7637-2 Pulse 5a (75 V/400 ms) without degradation. |
| Telecom Ethernet Interface Protection | Industrial Sensor Signal Line Protection |
Use Scenario: Secondary protection on PoE-powered Ethernet PHY power pins (e.g., 48 V PSE output) alongside primary GDT or polymer TVS. IC Role / Device Role / Timing Role: Fast-response secondary clamp limiting residual voltage after primary surge device, placed directly at PHY VDD pin. Use Value: 124 V VC ensures PHY ICs rated for 57 V absolute maximum survive combined surge events, meeting IEEE 802.3af/bt immunity requirements. |
Use Scenario: Protecting analog outputs (4–20 mA) and digital I/O (RS-485) of pressure/temperature sensors in factory automation systems. IC Role / Device Role / Timing Role: Low-capacitance unidirectional suppressor on sensor supply line, minimizing impact on signal integrity and response time. Use Value: SMB package allows placement within 2 mm of connector entry point; 125 °C/W thermal resistance supports operation in sealed enclosures up to 85 °C ambient. |
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-M3/H | Bidirectional variant with same VWM (78 V) but symmetric clamping in both polarities; VBR min/max = 88.1–94.4 V in each direction | Required where AC-coupled lines or reversible polarity interfaces (e.g., RS-485 differential pairs) need protection | Select SMBJ78A-M3/H only if bidirectional clamping is mandated; SMBJ78D-M3/H offers lower leakage and simpler grounding in DC-only rails |
| SMCJ78A-M3/H | Larger SMC (DO-214AB) package with higher PPPM (1500 W), identical VWM/VBR/VC specs, and RθJA = 50 °C/W | Suitable for higher-energy surge environments (e.g., outdoor telecom cabinets) requiring extended thermal margin | Choose SMCJ78A-M3/H when 600 W is insufficient or board layout permits larger footprint; SMBJ78D-M3/H optimizes space-constrained designs |
Compared with SMBJ78A-M3/H and SMCJ78A-M3/H, the SMBJ78D-M3/H delivers optimal balance of compact SMB footprint, 600 W surge capacity, and ultra-low leakage for DC power rail protection-making it preferred for space-limited industrial and automotive control units where unidirectional clamping suffices.
Availability
SMBJ78D-M3/H is available at Aetrix Electronics and suitable for industrial power supplies, automotive body electronics, telecom interface protection, and sensor signal conditioning requiring stable component supply and full RoHS/halogen-free compliance.
Supply support for SMBJ78D-M3/H 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, TVS devices, and optoelectronics with emphasis on reliability and application-specific performance.
The SMBJ series was engineered for high-power, surface-mount transient suppression in harsh environments-targeting industrial automation, automotive electronics, and communications infrastructure where precision clamping and long-term stability are essential.
FAQ
What is the maximum clamping voltage of SMBJ78D-M3/H at its rated peak pulse current?
The SMBJ78D-M3/H has a maximum clamping voltage (VC) of 124 V at its specified peak pulse current (IPPM) of 4.86 A, measured using the standard 10/1000 μs double-exponential surge waveform. This value defines the upper voltage limit imposed on protected circuitry during a worst-case transient event, ensuring downstream components remain within their absolute maximum ratings. The SMBJ78D-M3/H maintains this clamping performance across its full operating temperature range.
Is SMBJ78D-M3/H suitable for protecting 24 V automotive systems against load dump?
Yes, SMBJ78D-M3/H is commonly deployed for 24 V system load dump protection, particularly in commercial vehicle ECUs and industrial control modules. With a 78 V stand-off voltage and 124 V clamping level, it provides sufficient margin above typical 24 V nominal rails and transient peaks up to 100 V. Its 600 W rating meets ISO 16750-2 severity level IV requirements when used with appropriate PCB copper area for thermal dissipation.
Does SMBJ78D-M3/H have a bidirectional version, and how does it differ?
Yes, the bidirectional counterpart is SMBJ78A-M3/H (not SMBJ78CD). It shares identical VWM (78 V), VBR (88.1–94.4 V), and VC (124 V) specifications but clamps symmetrically in both directions-critical for AC-coupled or polarity-agnostic interfaces like RS-485 or antenna lines. SMBJ78D-M3/H exhibits <0.5 μA leakage only in reverse bias, whereas SMBJ78A-M3/H maintains low leakage in both polarities.
What is the thermal resistance and maximum power dissipation of SMBJ78D-M3/H at room temperature?
The SMBJ78D-M3/H has a typical junction-to-ambient thermal resistance (RθJA) of 125 °C/W when mounted on the minimum recommended PCB pad layout. At TA = 25 °C, its steady-state power dissipation (PD) is rated at 1.0 W; this drops to 5.0 W at TM = 50 °C when mounted on an infinite heatsink. Derating curves in the Vishay datasheet (Fig. 5) must be applied for operation above 25 °C ambient.
How does the M3/H suffix affect the packaging and compliance of SMBJ78D-M3/H?
The "M3" suffix indicates halogen-free, RoHS-compliant construction with JESD 201 Class 2 whisker resistance and UL 94 V-0 flammability rating. The "H" denotes packaging in 7″ diameter plastic tape and reel, with 750 units per reel. This configuration ensures compatibility with high-speed pick-and-place equipment and satisfies environmental and reliability requirements for industrial and automotive manufacturing.
SMBJ78D-M3/H Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AA, SMB
- Series:
- TransZorb®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 78V
- Voltage - Breakdown (Min):
- 88.1V
- Voltage - Clamping (Max) @ Ipp:
- 124V
- Current - Peak Pulse (10/1000µs):
- 4.86A
- 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 (SMBJ)
SMBJ78D-M3/H FAQ
1.How can I place an order for SMBJ78D-M3/H through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ78D-M3/H 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 SMBJ78D-M3/H reliable?
The price and inventory of SMBJ78D-M3/H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ78D-M3/H is usually 5 days.
3.What payment methods are accepted for SMBJ78D-M3/H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ78D-M3/H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ78D-M3/H?
SMBJ78D-M3/H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ78D-M3/H 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 SMBJ78D-M3/H?
For technical support, including SMBJ78D-M3/H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ78D-M3/H requirements.
6.How does Aetrix verify that SMBJ78D-M3/H is sourced from the original manufacturer or authorized distributors?
All SMBJ78D-M3/H 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 SMBJ78D-M3/H meets industry standards.
7.What is the process for return or replacement of SMBJ78D-M3/H?
All SMBJ78D-M3/H units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ78D-M3/H, 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 SMBJ78D-M3/H part is unused and in its original packaging.
Return procedure for SMBJ78D-M3/H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ78D-M3/H Tags
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