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Vishay General Semiconductor - Diodes Division SMBJ78AHE3/5B
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- Part No.:
- SMBJ78AHE3/5B
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ78AHE3/5B.pdf
- Description:
- TVS DIODE 78VWM 126VC DO214AA
- Quantity:
- Payment:
- Shipping:
Inventory:3,439
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Product details
Overview
SMBJ78AHE3/5B from Vishay General Semiconductor is a unidirectional surface-mount Transient Voltage Suppressor (TVS) diode in the 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), targeting protection of MOSFETs, ICs, and sensor interfaces in industrial power supplies.
For engineers reviewing the SMBJ78AHE3/5B datasheet, SMBJ78AHE3/5B pinout, SMBJ78AHE3/5B application, or SMBJ78AHE3/5B equivalent, key selection criteria include clamping voltage margin relative to protected circuit's absolute maximum rating, thermal derating above 25 °C ambient, junction-to-lead thermal resistance (20 °C/W), AEC-Q101 qualification status, and compatibility with automated SMT placement on 0.2" × 0.2" copper pads.
Technical Context
This TVS diode operates as a unidirectional avalanche clamp, triggered when reverse voltage exceeds its specified VBR range. Its glass-passivated junction ensures stable breakdown behavior and low leakage (<1.0 µA at VWM), while the low incremental surge resistance enables effective energy diversion during transient events.
The device is rated for 100 A non-repetitive forward surge current (IFSM, 8.3 ms half-sine), supports operating junction temperatures from –55 °C to +150 °C, and meets MSL Level 1 per J-STD-020 with peak reflow temperature up to 260 °C - confirming suitability for standard lead-free SMT assembly processes.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM (Stand-off Voltage) | 78 V - Maximum continuous reverse voltage before significant conduction begins; sets upper limit for normal circuit operation. |
| VBR (Breakdown Voltage) | 86.7–95.8 V at 1 mA - Confirmed avalanche onset range; defines minimum overvoltage threshold for clamping activation. |
| VC (Clamping Voltage) | 126 V at IPPM = 4.8 A - Peak voltage seen by protected circuit during 10/1000 µs transient; determines safe margin vs. IC/MOSFET abs max rating. |
| PPPM (Peak Pulse Power) | 600 W (10/1000 µs) - Energy-handling capability under standardized surge; validates robustness against common inductive switching transients. |
| RθJL (Junction-to-Lead Thermal Resistance) | 20 °C/W - Enables accurate thermal modeling of power dissipation during repetitive surges; critical for layout pad sizing and duty cycle validation. |
| TJ max. | +150 °C - Maximum allowable junction temperature; constrains ambient and PCB thermal design for sustained reliability. |
| AEC-Q101 Qualified | Yes - Confirmed qualification for automotive-grade reliability; required for under-hood and ADAS power rail protection applications. |
Pinout & Package
Package: SMB (DO-214AA), surface-mount, molded plastic case with matte tin-plated leads. Cathode indicated by band; polarity-critical for unidirectional operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward current entry / Reverse voltage reference | Connected to lower-potential side (e.g., ground or return path); reverse-biased during transient suppression. |
| Cathode | Clamping output / Surge sink node | Connected to protected line (e.g., 78 V rail); conducts surge current to anode when VAK > VBR. |
Key Features
| Feature | Design Value |
|---|---|
| 600 W peak pulse power (10/1000 µs) | Validates capability to absorb common industrial switching surges without degradation, supporting IEC 61000-4-5 Level 3 compliance when properly laid out. |
| AEC-Q101 qualified (HE3 suffix) | Confirms automotive-grade reliability including temperature cycling, humidity bias, and mechanical shock testing - required for OEM power module designs. |
| Low clamping ratio (VC/VBR ≈ 1.31) | Indicates efficient voltage limiting: clamps within 31% above breakdown, minimizing stress on downstream 100 V-rated MOSFETs or controllers. |
| MSL Level 1, 260 °C peak reflow | Enables single-pass lead-free reflow without moisture-related failure; eliminates need for baking prior to assembly. |
| Glass passivated junction | Ensures stable VBR tolerance and low leakage drift over time and temperature - critical for long-life industrial sensor interfaces. |
Applications
| Industrial Motor Drive DC Bus Protection | Automotive Body Control Module (BCM) Power Input |
|---|---|
|
Use Scenario: Suppresses inductive kickback from relay coils and solenoid drivers on 72–80 V DC bus rails in factory automation systems. IC Role / Device Role / Timing Role: Unidirectional TVS clamp placed between bus rail and chassis ground, activated within <1 ns upon overvoltage event. Use Value: Limits transient voltage to ≤126 V, protecting 100 V-rated gate drivers and MCU power supply inputs from damage during load dump or switch arcing. |
Use Scenario: Protects BCM 78 V input stage against jump-start surges and alternator load dump transients in 24 V commercial vehicles. IC Role / Device Role / Timing Role: Primary overvoltage clamp on main power entry, coordinated with upstream fuse and downstream LDO. Use Value: AEC-Q101 qualification and 126 V clamping ensure compliance with ISO 7637-2 Pulse 5a, preventing reset or latch-up of safety-critical microcontrollers. |
| Telecom Remote Radio Unit (RRU) Power Interface | Medical Imaging Power Supply Output Stage |
|
Use Scenario: Shields 78 V auxiliary power input of outdoor RRUs from lightning-induced surges on PoE-derived or solar-charged lines. IC Role / Device Role / Timing Role: First-line transient suppressor before DC/DC converter input, sized for 600 W single-event handling. Use Value: Low clamping voltage preserves margin for downstream 100 V input converters; SMB package allows dense layout near connector entry point. |
Use Scenario: Guards high-voltage X-ray generator power supply outputs against switching noise and arc-back transients in diagnostic equipment. IC Role / Device Role / Timing Role: Final-stage TVS on regulated 78 V output rail, ensuring patient-connected subsystems remain within SELV limits during fault conditions. Use Value: Verified 150 °C TJ max. and low leakage (<1 µA) support long-term stability in thermally constrained enclosures with no cooling fans. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ78AHM3/5B | Halogen-free, RoHS-compliant variant with identical electrical specs and AEC-Q101 qualification. | No functional difference; selected where halogen-free material compliance is mandated (e.g., EU medical or public infrastructure projects). | Choose SMBJ78AHM3/5B when halogen-free bill-of-materials requirements apply; otherwise, SMBJ78AHE3/5B is functionally identical. |
| SMCJ78AHE3/5B | Same VWM/VBR/VC ratings but in larger SMC (DO-214AB) package; higher PPPM (1500 W), lower RθJA (50 °C/W), same RθJL (20 °C/W). | Used where higher single-pulse energy (e.g., IEC 61000-4-5 Level 4) or improved thermal dissipation is needed, accepting larger footprint. | Choose SMCJ78AHE3/5B only if 1500 W surge rating or enhanced thermal performance justifies larger board area; SMBJ78AHE3/5B remains optimal for space-constrained 600 W applications. |
Compared with SMBJ78AHM3/5B, the SMBJ78AHE3/5B offers identical protection performance with standard RoHS compliance; versus SMCJ78AHE3/5B, it trades 600 W capability and SMB footprint for reduced board area - making it the preferred choice for compact 24/48 V system upgrades requiring AEC-Q101 validation.
Availability
SMBJ78AHE3/5B is available at Aetrix Electronics and suitable for industrial motor drives, automotive body control modules, telecom remote radio units, and medical imaging power supplies requiring stable component supply, AEC-Q101 traceability, and RoHS compliance.
Supply support for SMBJ78AHE3/5B 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, precision, and application-specific optimization.
The SMBJ series was developed for high-reliability transient suppression in space-constrained, high-volume SMT applications - particularly targeting automotive, industrial, and telecom power rail protection where AEC-Q101 qualification and consistent clamping performance are mandatory.
FAQ
What is the maximum clamping voltage of the SMBJ78AHE3/5B under a 10/1000 µs surge?
The SMBJ78AHE3/5B has a maximum clamping voltage (VC) of 126 V at a peak pulse current (IPPM) of 4.8 A using the standardized 10/1000 µs waveform. This value is measured per ANSI/IEEE C62.35 and confirmed in Vishay's datasheet revision 09-Jan-2024, Document Number 88392. The SMBJ78AHE3/5B maintains this clamping performance across its qualified operating temperature range.
Is SMBJ78AHE3/5B AEC-Q101 qualified, and what does that mean for automotive use?
Yes, the SMBJ78AHE3/5B is AEC-Q101 qualified, as indicated by the "HE3" suffix in its part number. This certification confirms it has passed rigorous stress tests including temperature cycling, high-temperature operating life, and mechanical shock - validating its suitability for automotive power electronics such as body control modules and engine control unit interfaces. The SMBJ78AHE3/5B meets these requirements without derating at full temperature range.
How does the SMBJ78AHE3/5B differ from bidirectional variants like SMBJ78CA?
The SMBJ78AHE3/5B is unidirectional, with polarity marked by a cathode band and intended for DC rail protection where reverse conduction must be blocked. In contrast, SMBJ78CA is bidirectional, lacks polarity marking, and clamps symmetrically in both directions - suited for AC signal lines or floating buses. The SMBJ78AHE3/5B's unidirectional structure delivers lower leakage (<1.0 µA at 78 V) and tighter VBR tolerance than its bidirectional counterpart.
What is the thermal resistance from junction to lead (RθJL) for SMBJ78AHE3/5B, and why does it matter?
The SMBJ78AHE3/5B has a typical junction-to-lead thermal resistance (RθJL) of 20 °C/W, per Vishay's datasheet. This parameter directly impacts how efficiently heat generated during surge events transfers from the silicon die to the PCB copper pads. A low RθJL enables more accurate thermal modeling for repetitive surge scenarios and supports reliable operation when mounted on the recommended 0.2" × 0.2" copper pads - critical for SMBJ78AHE3/5B deployment in high-duty-cycle industrial environments.
Can SMBJ78AHE3/5B be used in place of SMBJ75AHE3/5B or SMBJ85AHE3/5B?
No - the SMBJ78AHE3/5B is not a direct substitute for SMBJ75AHE3/5B or SMBJ85AHE3/5B due to differences in stand-off voltage (VWM = 78 V vs. 75 V or 85 V) and corresponding clamping behavior. Using SMBJ78AHE3/5B in a 75 V system risks insufficient margin before clamping; in an 85 V system, it may fail to activate during valid transients. Each SMBJ78AHE3/5B application must match its exact 78 V VWM rating to the protected circuit's nominal voltage and tolerance stack-up.
SMBJ78AHE3/5B 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:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AA (SMBJ)
SMBJ78AHE3/5B FAQ
1.How can I place an order for SMBJ78AHE3/5B through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ78AHE3/5B 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 SMBJ78AHE3/5B reliable?
The price and inventory of SMBJ78AHE3/5B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ78AHE3/5B is usually 5 days.
3.What payment methods are accepted for SMBJ78AHE3/5B?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ78AHE3/5B transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ78AHE3/5B?
SMBJ78AHE3/5B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ78AHE3/5B 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 SMBJ78AHE3/5B?
For technical support, including SMBJ78AHE3/5B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ78AHE3/5B requirements.
6.How does Aetrix verify that SMBJ78AHE3/5B is sourced from the original manufacturer or authorized distributors?
All SMBJ78AHE3/5B 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 SMBJ78AHE3/5B meets industry standards.
7.What is the process for return or replacement of SMBJ78AHE3/5B?
All SMBJ78AHE3/5B units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ78AHE3/5B, 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 SMBJ78AHE3/5B part is unused and in its original packaging.
Return procedure for SMBJ78AHE3/5B:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ78AHE3/5B Tags
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