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Vishay General Semiconductor - Diodes Division SMCJ78AHE3/9AT
- Part No.:
- SMCJ78AHE3/9AT
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SMCJ78AHE3/9AT.pdf
- Description:
- TVS DIODE 78VWM 126VC DO214AB
- Quantity:
- Payment:
- Shipping:
Inventory:2,007
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Product details
Overview
SMCJ78AHE3/9AT from Vishay General Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in SMC (DO-214AB) 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, 1500 W peak pulse power (10/1000 μs), 126 V maximum clamping voltage (VC) at 11.9 A IPPM, and operates across -55 °C to +150 °C junction temperature range - deployed in automotive ECUs and industrial motor drive power inputs.
For engineers reviewing the SMCJ78AHE3/9AT datasheet, SMCJ78AHE3/9AT pinout, SMCJ78AHE3/9AT application, or SMCJ78AHE3/9AT equivalent, this page delivers verified electrical parameters, AEC-Q101 qualification status, thermal resistance (RθJA = 75 °C/W), JEDEC-compliant SMC package dimensions, and real-world design implications for surge immunity in 24 V/48 V systems.
Technical Context
The SMCJ78AHE3/9AT employs a glass-passivated silicon junction optimized for fast response (<1 ns) to transient events such as ISO 7637-2 load dump or IEC 61000-4-5 surges. Its unidirectional polarity uses a cathode band marking and exhibits low incremental surge resistance, enabling effective clamping with minimal voltage overshoot during 10/1000 μs waveform transients.
Designed for surface-mount assembly on 8.0 mm × 8.0 mm copper pads per terminal, it meets MSL Level 1 per J-STD-020 (peak reflow 260 °C) and supports automated placement. The device is RoHS-compliant and AEC-Q101 qualified - confirmed by Vishay's HE3 suffix and documentation number 88394 (Rev. 09-Jan-2024).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 78 V - Maximum continuous reverse operating voltage before clamping begins; defines safe DC rail margin for 24 V/48 V systems. |
| VBR (min/max) | 86.7 V / 95.8 V at IT = 1 mA - Confirmed breakdown window ensures predictable turn-on without premature conduction. |
| VC @ IPPM | 126 V at 11.9 A - Clamping voltage under 1500 W 10/1000 μs surge; determines protected circuit's maximum transient exposure. |
| PPPM | 1500 W - Peak pulse power rating; enables single-event suppression of high-energy transients like automotive load dump. |
| RθJA | 75 °C/W - Junction-to-ambient thermal resistance on standard PCB layout; informs derating above TA = 25 °C per Fig. 2. |
| TJ max. | +150 °C - Maximum junction temperature; supports operation in under-hood automotive environments and industrial enclosures. |
| AEC-Q101 | Qualified - Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD per AEC specification. |
Pinout & Package
Package: SMC (DO-214AB), molded case with matte tin-plated leads, UL 94 V-0 rated compound, 0.305" × 0.220" footprint (7.75 mm × 5.59 mm), cathode band marking for polarity identification.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side connection point | Connected to ground or return path; completes current loop during transient clamping event. |
| Cathode | High-side connection point | Connected to protected line (e.g., 24 V rail); marked with band; carries full surge current into ground. |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Ensures stable VBR over lifetime and improved humidity resistance vs. epoxy-passivated alternatives. |
| MSL Level 1 rating | Enables direct placement onto reflow soldering lines without baking; peak temperature tolerance up to 260 °C. |
| Low incremental surge resistance | Minimizes VC rise under high-current transients, improving protection margin for downstream MOSFETs and controllers. |
| AEC-Q101 qualification | Validates suitability for automotive power modules, body control units, and ADAS sensor supply rails. |
| 1500 W 10/1000 μs capability | Meets ISO 7637-2 Pulse 5a (load dump) requirements for 24 V systems without external series impedance. |
Applications
| Automotive Power Input Protection | Industrial Motor Drive DC Bus |
|---|---|
|
Use Scenario: Protecting 24 V battery-fed ECUs against load dump transients per ISO 7637-2. IC Role / Device Role / Timing Role: Unidirectional TVS placed between battery rail and input filter capacitor. Use Value: Clamps 126 V peak at 11.9 A, limiting stress on upstream fuse and downstream DC-DC converter ICs. |
Use Scenario: Safeguarding 48 V DC bus in servo drives from switching-induced voltage spikes. IC Role / Device Role / Timing Role: Parallel-connected TVS absorbing energy from IGBT turn-off overshoot. Use Value: 1500 W rating handles repetitive 10/1000 μs surges common in PWM-driven motor inverters. |
| Telecom Power Supply Input | Medical Equipment DC Rail |
|
Use Scenario: Shielding PoE-powered network switches from lightning-induced surges on 48 V input. IC Role / Device Role / Timing Role: First-line transient suppressor ahead of primary DC-DC stage. Use Value: 78 V VWM provides headroom above nominal 48 V while maintaining fast <1 ns response. |
Use Scenario: Securing isolated 24 V auxiliary supply in diagnostic imaging devices. IC Role / Device Role / Timing Role: AEC-Q101-qualified TVS ensuring long-term reliability in safety-critical subsystems. Use Value: +150 °C TJ max and RθJA = 75 °C/W support operation in thermally constrained enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SAC78AHE3/9AT | Lower PPPM (600 W), same VWM/VBR range, smaller SMA package (DO-214AC), higher RθJA (120 °C/W) | Better suited for space-constrained, lower-energy applications; not recommended for ISO 7637-2 load dump. | Select only when board area is critical and surge energy ≤600 W. |
| SMCJ78CAHE3/9AT | Bidirectional variant; identical VWM/VBR/PPPM but symmetrical clamping in both polarities; no cathode band | Required for AC-coupled signal lines or floating DC rails where reverse polarity transients occur. | Choose bidirectional version only if system experiences reversible surges (e.g., RS-485 data lines). |
Compared with SAC78AHE3/9AT and SMCJ78CAHE3/9AT, the SMCJ78AHE3/9AT uniquely balances 1500 W surge capacity, AEC-Q101 qualification, and SMC package thermal performance - making it the preferred choice for high-reliability 24 V/48 V power rail protection where unidirectional clamping suffices.
Availability
SMCJ78AHE3/9AT is available at Aetrix Electronics and suitable for automotive electronic control units, industrial motor drives, telecom power supplies, and medical equipment requiring stable component supply with AEC-Q101 assurance and long-lifecycle support.
Supply support for SMCJ78AHE3/9AT 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, efficiency, and automotive-grade validation.
The SMCJ78AHE3/9AT belongs to Vishay's TRANSZORB® SMCJ family - engineered specifically for high-power transient suppression in harsh-environment applications including automotive, industrial, and telecom infrastructure.
FAQ
What is the clamping voltage of the SMCJ78AHE3/9AT under a 10/1000 μs surge?
The SMCJ78AHE3/9AT has a maximum clamping voltage (VC) of 126 V at 11.9 A peak pulse current (IPPM), measured under the standardized 10/1000 μs waveform. This value is critical for determining whether downstream components like DC-DC controllers or microcontrollers remain within their absolute maximum voltage ratings during surge events. The 126 V VC directly reflects the device's ability to limit transient overvoltage on a 78 V nominal rail.
Is the SMCJ78AHE3/9AT qualified for automotive use?
Yes, the SMCJ78AHE3/9AT is AEC-Q101 qualified, as confirmed by its HE3 suffix and Vishay documentation number 88394 (Rev. 09-Jan-2024). This qualification covers stress tests including high-temperature reverse bias (HTRB), temperature cycling, and ESD, validating its suitability for under-hood and chassis-mounted automotive applications such as body control modules and ADAS power supplies.
What does the "9AT" suffix indicate in SMCJ78AHE3/9AT?
The "9AT" suffix denotes the packaging configuration: 13-inch diameter plastic tape and reel, with a base quantity of 3500 units per reel. This format is optimized for high-volume SMT assembly lines and is distinct from the "57T" (7-inch reel, 850 units) option. The "HE3" portion confirms RoHS compliance and AEC-Q101 qualification, while "A" specifies unidirectional polarity.
How does the SMCJ78AHE3/9AT differ from the bidirectional SMCJ78CAHE3/9AT?
The SMCJ78AHE3/9AT is unidirectional with a cathode band marking and conducts only in reverse bias, whereas the SMCJ78CAHE3/9AT is bidirectional with symmetrical clamping in both directions and no polarity marking. Both share identical VWM (78 V), VBR (86.7–95.8 V), PPPM (1500 W), and package (SMC), but the unidirectional version offers slightly lower leakage and is preferred for DC power rail protection where polarity is fixed.
What is the thermal resistance of the SMCJ78AHE3/9AT, and how does it affect layout?
The SMCJ78AHE3/9AT has a typical junction-to-ambient thermal resistance (RθJA) of 75 °C/W when mounted on 0.31" × 0.31" (8.0 mm × 8.0 mm) copper pads per terminal. This value requires PCB designers to allocate sufficient copper area for heat dissipation during repetitive surge events; reducing pad size increases RθJA and risks thermal runaway. Layout must follow Vishay's recommended mounting pad dimensions in Document 88394 to maintain rated performance.
SMCJ78AHE3/9AT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AB, SMC
- 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):
- 11.9A
- Power - Peak Pulse:
- 1500W (1.5kW)
- 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-214AB (SMCJ)
SMCJ78AHE3/9AT FAQ
1.How can I place an order for SMCJ78AHE3/9AT through Aetrix?
Please submit a Request for Quotation (RFQ) for SMCJ78AHE3/9AT 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 SMCJ78AHE3/9AT reliable?
The price and inventory of SMCJ78AHE3/9AT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMCJ78AHE3/9AT is usually 5 days.
3.What payment methods are accepted for SMCJ78AHE3/9AT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMCJ78AHE3/9AT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMCJ78AHE3/9AT?
SMCJ78AHE3/9AT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMCJ78AHE3/9AT 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 SMCJ78AHE3/9AT?
For technical support, including SMCJ78AHE3/9AT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMCJ78AHE3/9AT requirements.
6.How does Aetrix verify that SMCJ78AHE3/9AT is sourced from the original manufacturer or authorized distributors?
All SMCJ78AHE3/9AT 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 SMCJ78AHE3/9AT meets industry standards.
7.What is the process for return or replacement of SMCJ78AHE3/9AT?
All SMCJ78AHE3/9AT units undergo pre-shipment inspection (PSI). If there is an issue with SMCJ78AHE3/9AT, 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 SMCJ78AHE3/9AT part is unused and in its original packaging.
Return procedure for SMCJ78AHE3/9AT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMCJ78AHE3/9AT Tags
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