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Vishay General Semiconductor - Diodes Division SMBJ78AHM3_B/H
- Part No.:
- SMBJ78AHM3_B/H
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ78AHM3_B/H.pdf
- Description:
- 600W,78V 5%,UNIDIR,SMB TVS
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
SMBJ78AHM3_B/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), 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 rating with 10/1000 µs waveform - deployed in industrial motor drives, automotive body control modules, and telecom power supplies.
For engineers reviewing the SMBJ78AHM3_B/H datasheet, SMBJ78AHM3_B/H pinout, SMBJ78AHM3_B/H application, or SMBJ78AHM3_B/H equivalent, this page delivers verified electrical parameters, thermal derating behavior, clamping performance under surge conditions, AEC-Q101 qualification status, and real-world design implications for PCB layout, surge immunity validation, and reliability-critical transient suppression.
Technical Context
This TVS diode operates as a unidirectional avalanche clamp, conducting only when reverse voltage exceeds VBR to shunt transient energy away from protected circuitry. Its low incremental surge resistance ensures minimal voltage overshoot during fast transients, while the glass-passivated junction guarantees stable breakdown characteristics across temperature and lifetime.
The device is rated for 100 A non-repetitive forward surge current (IFSM) and supports continuous power dissipation of 5.0 W on infinite heatsink at 50 °C. Junction-to-ambient thermal resistance is 100 °C/W, requiring careful pad design per Vishay's recommended 0.2" × 0.2" copper pads to sustain repetitive surge duty cycles up to 0.01%.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM (Stand-off Voltage) | 78 V - Maximum continuous reverse operating voltage before significant leakage; defines safe DC rail margin before clamping initiates. |
| VBR (Breakdown Voltage) | 86.7–95.8 V at 1 mA - Confirmed avalanche onset range; determines minimum overvoltage threshold for protection activation. |
| VC (Clamping Voltage) | 126 V at IPPM = 4.8 A - Peak voltage seen by protected IC during 10/1000 µs surge; directly limits stress on downstream components. |
| PPPM (Peak Pulse Power) | 600 W - Sustained transient energy handling capability under standard 10/1000 µs waveform; validates compliance with IEC 61000-4-5 Level 4. |
| IFSM (Surge Current) | 100 A - Single half-sine 8.3 ms surge rating; supports protection against inductive switch-off events in relay or solenoid circuits. |
| TJ max. | 150 °C - Maximum junction temperature; sets upper limit for thermal design margin in enclosed or high-ambient environments. |
| Package | SMB (DO-214AA) - Surface-mount outline with cathode band marking; compatible with automated placement and reflow profiles up to 260 °C peak. |
Pinout & Package
Package: SMB (DO-214AA), surface-mount, unidirectional polarity marked by cathode band. Dimensions: 4.57 mm × 3.94 mm × 2.20 mm (L × W × H), with 1.52 mm lead spacing and matte tin-plated terminals compliant with J-STD-002 solderability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to ground or lowest potential node; completes conduction path during reverse-biased transient event. |
| Cathode | High-side input terminal | Connected to protected line (e.g., 78 V rail); carries full surge current into anode during clamping operation. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, humidity testing, and mechanical shock - suitable for under-hood and body electronics. |
| 600 W peak pulse power | Enables single-device protection against severe transients per ISO 7637-2 Pulse 5a (load dump) without external series impedance. |
| Low clamping ratio (VC/VBR ≈ 1.31) | Minimizes overvoltage margin between breakdown and clamping, reducing risk of damage to sensitive 80 V-rated MOSFETs or gate drivers. |
| MSL Level 1 moisture sensitivity | Allows unlimited floor life and standard reflow without baking - simplifies manufacturing and reduces assembly cost. |
| Halogen-free & RoHS-compliant (HM3 suffix) | Meets environmental compliance requirements for export to EU, China, and Japan without material declaration exceptions. |
Applications
| Industrial Motor Drives | Automotive Body Control Modules |
|---|---|
Use Scenario: Protection of 72–80 V DC bus in brushless DC motor controllers against inductive kickback from H-bridge switching. IC Role / Device Role / Timing Role: Unidirectional TVS placed across DC link capacitor to clamp voltage spikes exceeding 78 V. Use Value: Limits transient voltage to ≤126 V, preventing gate oxide rupture in 100 V Si MOSFETs and ensuring >100,000-cycle reliability under repeated load switching. |
Use Scenario: Surge suppression on LIN bus power supply rail in door module ECUs exposed to battery disconnect transients. IC Role / Device Role / Timing Role: Standoff-clamp TVS connected between VBAT and GND, responding within <1 ns to sub-100 ns spikes. Use Value: Withstands 100 A IFSM surges and maintains clamping below 130 V, preserving communication integrity during cold-crank and jump-start events. |
| Telecom Power Supplies | Renewable Energy Inverters |
Use Scenario: Input-stage protection of 48–72 V telecom rectifiers subjected to lightning-induced surges on AC input lines. IC Role / Device Role / Timing Role: Primary TVS on DC output side, coordinated with upstream MOVs to handle differential-mode transients. Use Value: 600 W PPPM rating enables coordination with 10 kA MOVs to absorb >90% of 10/1000 µs energy, reducing thermal stress on secondary regulation stages. |
Use Scenario: DC-link protection in solar microinverters where PV string voltages reach 75–85 V under open-circuit conditions. IC Role / Device Role / Timing Role: Clamp device across DC bus capacitors to suppress voltage doubling during rapid MPPT transitions. Use Value: 150 °C TJ max and halogen-free HM3 construction support long-term operation in outdoor enclosures with ambient temperatures up to 85 °C. |
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_B/H | Same electrical specs and SMB package, but RoHS-compliant commercial grade (E3) without halogen-free certification. | Lacks halogen-free compliance; not acceptable for automotive or green-certified industrial programs requiring IEC 61249-2-21. | Select SMBJ78AHM3_B/H when halogen-free materials are mandated; choose SMBJ78AHE3_B/H for cost-sensitive commercial designs without environmental restrictions. |
| SMBJ78A-M3/52 | Identical HM3 specification but shipped in 750-unit 7" tape-and-reel (52 code); SMBJ78AHM3_B/H uses same packaging format with B/H revision marking. | No functional difference; B/H denotes manufacturing revision level per Vishay's internal traceability system. | SMBJ78AHM3_B/H and SMBJ78A-M3/52 are functionally interchangeable - B/H adds revision tracking for lot-specific qualification records. |
Compared with SMBJ78AHE3_B/H, SMBJ78AHM3_B/H provides halogen-free compliance critical for automotive OEMs; versus SMBJ78A-M3/52, it offers identical performance with enhanced revision-level traceability for production audits and PPAP submissions.
Availability
SMBJ78AHM3_B/H is available at Aetrix Electronics and suitable for industrial motor drives, automotive body control modules, and telecom power supplies requiring stable component supply, AEC-Q101 qualification, and halogen-free compliance.
Supply support for SMBJ78AHM3_B/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, and protection devices with emphasis on reliability, power efficiency, and automotive-grade qualification.
The SMBJ series was developed specifically for high-energy transient suppression in harsh environments - targeting automotive, industrial, and telecom systems where failure modes must be mitigated without adding complexity or board space.
FAQ
What is the clamping voltage of SMBJ78AHM3_B/H at its rated peak pulse current?
The SMBJ78AHM3_B/H has a maximum clamping voltage (VC) of 126 V at its specified peak pulse current (IPPM) of 4.8 A, measured using the standard 10/1000 µs waveform. This value defines the upper voltage limit imposed on protected circuitry during surge events and is critical for ensuring compatibility with 100 V-rated downstream components such as MOSFETs and gate drivers. The SMBJ78AHM3_B/H maintains this clamping performance across its full operating temperature range.
Is SMBJ78AHM3_B/H qualified for automotive applications?
Yes, SMBJ78AHM3_B/H is AEC-Q101 qualified, meaning it has passed rigorous stress tests including temperature cycling, highly accelerated life testing (HALT), and mechanical shock - all required for use in automotive electronic control units. The HM3 suffix confirms halogen-free, RoHS-compliant construction aligned with automotive material standards. Engineers deploying SMBJ78AHM3_B/H in body control modules or ADAS power domains can rely on its validated reliability under extended temperature and vibration profiles.
How does the SMBJ78AHM3_B/H differ from the SMBJ78A-E3/52 variant?
The SMBJ78AHM3_B/H differs from SMBJ78A-E3/52 primarily in material composition: HM3 denotes halogen-free, RoHS-compliant construction, whereas E3 is RoHS-compliant but not halogen-free. Both share identical electrical specifications, SMB package, and AEC-Q101 qualification. The "B/H" suffix in SMBJ78AHM3_B/H indicates a specific manufacturing revision level for traceability, while E3/52 uses Vishay's standard commercial packaging code. Designers selecting SMBJ78AHM3_B/H meet stricter environmental mandates without sacrificing performance.
What is the thermal resistance of SMBJ78AHM3_B/H, and how does it affect PCB layout?
The SMBJ78AHM3_B/H has a typical junction-to-ambient thermal resistance (RθJA) of 100 °C/W when mounted on minimum recommended pads, and 20 °C/W junction-to-lead (RθJL). To maintain safe junction temperatures during repetitive surges, Vishay specifies 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal. Reducing pad area increases thermal impedance, risking premature thermal runaway during sustained transient activity - so PCB layout for SMBJ78AHM3_B/H must strictly follow the outlined copper area guidelines.
Can SMBJ78AHM3_B/H be used in bidirectional protection circuits?
No, SMBJ78AHM3_B/H is a unidirectional TVS diode, indicated by the "A" suffix and cathode band marking. It conducts only in reverse bias above VBR and blocks forward current like a standard diode. For bidirectional protection - such as AC line or data bus applications - a part with "CA" suffix (e.g., SMBJ78CA) is required. Using SMBJ78AHM3_B/H in a bidirectional configuration would result in unintended forward conduction and possible failure; always verify polarity alignment in schematic capture and layout for SMBJ78AHM3_B/H.
SMBJ78AHM3_B/H Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AA, SMB
- Series:
- TransZorb®
- Packaging:
- Bulk
- Product Status:
- Active
- 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_B/H FAQ
1.How can I place an order for SMBJ78AHM3_B/H through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ78AHM3_B/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 SMBJ78AHM3_B/H reliable?
The price and inventory of SMBJ78AHM3_B/H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ78AHM3_B/H is usually 5 days.
3.What payment methods are accepted for SMBJ78AHM3_B/H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ78AHM3_B/H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ78AHM3_B/H?
SMBJ78AHM3_B/H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ78AHM3_B/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 SMBJ78AHM3_B/H?
For technical support, including SMBJ78AHM3_B/H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ78AHM3_B/H requirements.
6.How does Aetrix verify that SMBJ78AHM3_B/H is sourced from the original manufacturer or authorized distributors?
All SMBJ78AHM3_B/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 SMBJ78AHM3_B/H meets industry standards.
7.What is the process for return or replacement of SMBJ78AHM3_B/H?
All SMBJ78AHM3_B/H units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ78AHM3_B/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 SMBJ78AHM3_B/H part is unused and in its original packaging.
Return procedure for SMBJ78AHM3_B/H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ78AHM3_B/H Tags
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