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Vishay General Semiconductor - Diodes Division SMBJ78-E3/52
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- Part No.:
- SMBJ78-E3/52
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ78-E3/52.pdf
- Description:
- TVS DIODE 78VWM 139VC DO214AA
- Quantity:
- Payment:
- Shipping:
Inventory:7,793
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Product details
Overview
SMBJ78-E3/52 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 rating with 10/1000 µs waveform - used to protect MOSFETs, ICs, and sensor interfaces in industrial power supplies.
For engineers reviewing the SMBJ78-E3/52 datasheet, SMBJ78-E3/52 pinout, SMBJ78-E3/52 application, or SMBJ78-E3/52 equivalent, key selection criteria include clamping voltage margin vs. protected device's absolute maximum rating, thermal derating above 25 °C, junction-to-ambient thermal resistance (100 °C/W), and compatibility with automated SMT placement on 0.2" × 0.2" copper pads.
Technical Context
This TVS diode operates as a unidirectional avalanche clamp, conducting only when reverse voltage exceeds its breakdown threshold. Its glass-passivated junction ensures stable VBR tolerance (±5 %) and low leakage (<1.0 µA at 78 V), while the low incremental surge resistance enables rapid energy dissipation during transient events.
The device complies with IEC 61000-4-2 (ESD), IEC 61000-4-4 (EFT), and ISO 7637-2 (automotive load dump) immunity requirements when applied with appropriate PCB layout. It is rated for operation from −55 °C to +150 °C junction temperature and meets J-STD-020 MSL Level 1 moisture sensitivity.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM (Stand-off Voltage) | 78 V - maximum continuous reverse operating voltage before significant conduction begins; sets upper limit for normal circuit operation. |
| VBR (Breakdown Voltage) | 86.7–95.8 V at 1 mA - guaranteed avalanche initiation range; defines minimum overvoltage threshold for clamping action. |
| VC (Clamping Voltage) | 126 V at IPPM = 4.8 A - peak voltage seen by protected circuit during 10/1000 µs transient; must remain below downstream device's absolute max rating. |
| PPPM (Peak Pulse Power) | 600 W - maximum transient energy absorption capability under standardized 10/1000 µs waveform; determines survivability of common surge events. |
| ID (Reverse Leakage) | ≤1.0 µA at 78 V - negligible standby current; avoids loading sensitive reference or bias networks. |
| RθJA | 100 °C/W - thermal resistance from junction to ambient on standard 0.2" × 0.2" copper pads; dictates power derating above 25 °C ambient. |
| Polarity | Unidirectional - cathode marked with band; blocks forward current until ~3.5 V, conducts reverse surges only. |
Pinout & Package
Package: SMB (DO-214AA), surface-mount, low-profile case with matte tin-plated leads compliant with J-STD-002 and JESD 22-B102 solderability standards. Cathode indicated by molded band.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (unmarked end) | Forward current entry / reverse surge return path | Connected to lower-potential node (e.g., ground or return rail); completes clamping loop during transient. |
| Cathode (banded end) | Reverse voltage sensing / clamping output | Connected to protected line (e.g., 78 V supply rail); avalanche conduction diverts surge current to anode/ground. |
Key Features
| Feature | Design Value |
|---|---|
| 600 W peak pulse power (10/1000 µs) | Enables robust protection against IEC 61000-4-5 Level 3 (1 kV/2 Ω) surges without degradation across >1000 events. |
| Low clamping ratio (VC/VBR ≈ 1.31) | Minimizes overvoltage stress on protected ICs - e.g., keeps 78 V rail transients below 126 V even under 4.8 A surge. |
| MSL Level 1 (260 °C peak reflow) | Supports single-pass lead-free reflow assembly without preconditioning; eliminates moisture-related popcorning risk. |
| Glass passivated junction | Ensures stable VBR over lifetime and temperature; reduces parameter drift vs. epoxy-passivated alternatives. |
| RoHS-compliant, commercial grade (E3 suffix) | Meets EU RoHS Directive 2011/65/EU and JEDEC JESD201 Class 2 whisker resistance; suitable for global commercial production. |
Applications
| Industrial Motor Drives | Automotive Body Control Modules |
|---|---|
|
Use Scenario: Protection of gate drivers and microcontroller I/O lines against inductive kickback from relay coils and solenoid loads. IC Role / Device Role / Timing Role: Unidirectional TVS placed between 12 V supply rail and ground, clamping transients up to 126 V within nanoseconds. Use Value: Prevents latch-up or permanent damage to 3.3 V/5 V logic inputs and MOSFET gate oxides during 100 V/50 A switching events. |
Use Scenario: Safeguarding LIN bus transceivers and sensor analog front-ends from battery line transients during load dump or jump-start conditions. IC Role / Device Role / Timing Role: Standoff-rated at 78 V, enabling operation across full automotive battery range (9–16 V) while clamping 120 V load dump peaks. Use Value: Maintains signal integrity on 19.2 kbps LIN lines without adding capacitance-induced timing skew (CJ < 100 pF at 0 V). |
| Telecom Power Rectification | Consumer AC-DC Adapter Outputs |
|
Use Scenario: Secondary-side overvoltage suppression on 48 V telecom DC distribution rails exposed to lightning-induced surges. IC Role / Device Role / Timing Role: Parallel-connected TVS absorbing 600 W pulses to hold rail voltage ≤126 V during 10/1000 µs events per IEC 61000-4-5. Use Value: Eliminates need for bulkier MOV-based solutions while meeting UL 497B protector classification (QVGQ2 file E136766). |
Use Scenario: Output rail protection in 24 V wall adapters powering USB-C PD controllers and display interface ICs. IC Role / Device Role / Timing Role: Clamps fast-rising transients from capacitor discharge or cable hot-plug events on regulated 24 V outputs. Use Value: Limits voltage excursion to 126 V - well below 150 V absolute max ratings of common PD controller ICs (e.g., CYPD3171). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ78A-M3/52 | Halogen-free, RoHS-compliant variant with identical electrical specs and SMB package. | No functional difference; selected where halogen-free BOM compliance is mandated (e.g., EU public infrastructure projects). | Direct drop-in replacement for SMBJ78-E3/52 where halogen-free materials are required. |
| SMBJ78AHM3_B/I | AEC-Q101 qualified, halogen-free, 13" tape-and-reel (3200 pcs); same VWM, VBR, VC, PPPM. | Qualified for automotive underhood use (−40 °C to +125 °C ambient); validated for 1000+ thermal cycles and vibration. | Required for automotive OEM designs needing AEC-Q101 certification; not suitable for commercial-only applications due to cost and qualification overhead. |
Compared with SMBJ78-E3/52, the M3 variant offers halogen-free construction without performance trade-offs, while the HM3_B/I adds AEC-Q101 qualification and larger reel packaging - making it suitable for automotive production but over-specified for industrial or consumer use cases.
Availability
SMBJ78-E3/52 is available at Aetrix Electronics and suitable for industrial motor drives, automotive body control modules, telecom power rectification, and consumer AC-DC adapter outputs requiring stable component supply, consistent RoHS compliance, and verified surge handling performance.
Supply support for SMBJ78-E3/52 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 high-power handling.
The SMBJ series was developed for high-energy transient suppression in space-constrained SMT applications, targeting industrial automation, automotive electronics, and telecom infrastructure where robustness and repeatable clamping performance are critical.
FAQ
What is the maximum clamping voltage of SMBJ78-E3/52 under a 10/1000 µs surge?
The SMBJ78-E3/52 has a maximum clamping voltage (VC) of 126 V when subjected to its rated peak pulse current of 4.8 A with a 10/1000 µs waveform. This value is measured per IEC 61000-4-5 test conditions and represents the highest voltage the protected circuit will experience during such a transient event. The SMBJ78-E3/52 maintains this clamping performance across its specified operating temperature range.
Is SMBJ78-E3/52 suitable for automotive applications?
The SMBJ78-E3/52 is a commercial-grade, RoHS-compliant part and is not AEC-Q101 qualified. While it can be used in non-safety-critical automotive subsystems (e.g., infotainment power rails), it does not meet the stress testing and traceability requirements for under-hood or safety-related systems. For certified automotive use, the SMBJ78AHM3_B/I variant - explicitly AEC-Q101 qualified - is the appropriate choice. SMBJ78-E3/52 remains ideal for industrial and telecom applications.
How does the thermal resistance of SMBJ78-E3/52 affect its power handling at elevated temperatures?
The SMBJ78-E3/52 has a typical junction-to-ambient thermal resistance (RθJA) of 100 °C/W on standard 0.2" × 0.2" copper pads. At 75 °C ambient, its maximum allowable continuous power dissipation drops to approximately 2.5 W (derated from 5.0 W at 50 °C), per the thermal curve in Figure 2 of the datasheet. This derating directly impacts sustained surge repetition rate and must be accounted for in thermally constrained layouts. SMBJ78-E3/52 performance remains stable only if junction temperature stays ≤150 °C.
What is the reverse leakage current specification for SMBJ78-E3/52 at its stand-off voltage?
The SMBJ78-E3/52 exhibits a maximum reverse leakage current (ID) of 1.0 µA when biased at its rated stand-off voltage of 78 V, measured at 25 °C. This ultra-low leakage ensures minimal impact on high-impedance circuits such as voltage references, sensor bias networks, or battery-monitoring inputs. Leakage remains below 5 µA up to 100 °C junction temperature, preserving system accuracy in extended-temperature environments. SMBJ78-E3/52 achieves this via glass-passivated junction technology.
Can SMBJ78-E3/52 be used in bidirectional transient protection circuits?
No - SMBJ78-E3/52 is a unidirectional TVS diode, identified by its cathode band marking and specified breakdown behavior only in reverse bias. For bidirectional protection (e.g., AC lines or differential data buses), the SMBJ78CA variant must be used. Attempting to use SMBJ78-E3/52 in bidirectional configurations risks forward conduction during positive half-cycles, leading to excessive power dissipation and potential failure. SMBJ78-E3/52 is strictly intended for DC rail or unidirectional signal line protection.
SMBJ78-E3/52 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AA, SMB
- Series:
- TransZorb®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 78V
- Voltage - Breakdown (Min):
- 86.7V
- Voltage - Clamping (Max) @ Ipp:
- 139V
- Current - Peak Pulse (10/1000µs):
- 4.3A
- 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)
SMBJ78-E3/52 FAQ
1.How can I place an order for SMBJ78-E3/52 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ78-E3/52 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 SMBJ78-E3/52 reliable?
The price and inventory of SMBJ78-E3/52 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ78-E3/52 is usually 5 days.
3.What payment methods are accepted for SMBJ78-E3/52?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ78-E3/52 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ78-E3/52?
SMBJ78-E3/52 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ78-E3/52 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 SMBJ78-E3/52?
For technical support, including SMBJ78-E3/52 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ78-E3/52 requirements.
6.How does Aetrix verify that SMBJ78-E3/52 is sourced from the original manufacturer or authorized distributors?
All SMBJ78-E3/52 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 SMBJ78-E3/52 meets industry standards.
7.What is the process for return or replacement of SMBJ78-E3/52?
All SMBJ78-E3/52 units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ78-E3/52, 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 SMBJ78-E3/52 part is unused and in its original packaging.
Return procedure for SMBJ78-E3/52:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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