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Vishay General Semiconductor - Diodes Division SMBJ78A-E3/52
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- Part No.:
- SMBJ78A-E3/52
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ78A-E3/52.pdf
- Description:
- TVS DIODE 78VWM 126VC DO214AA
- Quantity:
- Payment:
- Shipping:
Inventory:1,445
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Product details
Overview
SMBJ78A-E3/52 from Vishay General Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in SMB (DO-214AA) package, designed to protect sensitive electronics against ESD, lightning-induced surges, and inductive switching transients. 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, and 600 W peak pulse power rating with 10/1000 µs waveform.
For engineers reviewing the SMBJ78A-E3/52 datasheet, SMBJ78A-E3/52 pinout, SMBJ78A-E3/52 application, or SMBJ78A-E3/52 equivalent, key selection considerations include its unidirectional polarity, 1.0 µA max reverse leakage at VWM, 150 °C max junction temperature, RoHS-compliant matte tin-plated leads, and suitability for industrial power supply rail protection and automotive sensor interface surge suppression.
Technical Context
This TVS diode operates as a voltage-clamping device in series with the protected line and ground, entering avalanche conduction when transient voltage exceeds VBR. Its glass-passivated silicon junction ensures stable breakdown characteristics and low incremental surge resistance (<10 Ω typical), enabling fast response time (<1 ns) and consistent clamping performance across temperature.
The SMBJ78A-E3/52 is rated for 600 W peak pulse power under standardized 10/1000 µs waveform, with derating above 25 °C per Fig. 2 of the datasheet. Its thermal resistance (RθJA = 100 °C/W) assumes mounting on 0.2" × 0.2" copper pads, and it meets MSL Level 1 per J-STD-020 with 260 °C reflow peak.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 78 V - Maximum continuous reverse operating voltage before clamping begins; defines safe DC/AC working range. |
| VBR (min/max) | 86.7 V / 95.8 V at IT = 1 mA - Confirmed breakdown threshold range; ensures reliable turn-on margin above VWM. |
| VC @ IPPM | 126 V at 4.8 A - Clamped voltage during 600 W surge; determines maximum stress imposed on downstream ICs. |
| IPPM | 4.8 A - Peak pulse current capability with 10/1000 µs waveform; directly supports IEC 61000-4-5 Level 3 (1 kV/2 Ω) surge immunity. |
| PPPM | 600 W - Peak pulse power handling; enables robust protection against repetitive transients up to 0.01% duty cycle. |
| RθJA | 100 °C/W - Junction-to-ambient thermal resistance; requires minimum 0.2" × 0.2" copper pad per terminal for rated power dissipation. |
| TJ max | +150 °C - Maximum junction temperature; supports operation in under-hood automotive and industrial ambient environments. |
Pinout & Package
Package: SMB (DO-214AA), surface-mount, low-profile plastic case with matte tin-plated leads solderable per J-STD-002 and JESD 22-B102. Polarity indicated by cathode band; anode and cathode terminals are axially oriented.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Input/Line side (for unidirectional configuration) | Connected to protected signal or power line; current flows from cathode to anode during clamping. |
| Cathode | Ground-reference side | Connected to system ground or low-impedance return path; defines directionality and clamping reference point. |
Key Features
| Feature | Design Value |
|---|---|
| 600 W peak pulse power (10/1000 µs) | Supports IEC 61000-4-5 surge testing without degradation; validated for ≥1000 pulses at rated conditions. |
| Glass passivated junction | Ensures stable VBR tolerance and long-term reliability under thermal cycling and humidity exposure. |
| MSL Level 1 (260 °C peak) | Enables standard SMT reflow assembly without moisture sensitivity concerns or baking requirements. |
| RoHS-compliant, commercial grade (E3 suffix) | Meets EU RoHS Directive 2011/65/EU; no lead, mercury, cadmium, hexavalent chromium, PBB, or PBDE. |
| Low incremental surge resistance | Minimizes VC overshoot during fast-rising transients; critical for protecting MOSFET gates and logic inputs. |
Applications
| Industrial Power Supply Protection | Automotive Sensor Interface Protection |
|---|---|
|
Use Scenario: Protecting 24 V DC input rails in programmable logic controllers (PLCs) and motor drives from load dump and inductive kickback. IC Role / Device Role / Timing Role: Unidirectional clamping TVS placed between input rail and chassis ground to limit transient overvoltage to ≤126 V. Use Value: Prevents damage to upstream DC-DC converters and downstream microcontrollers during 100 V/50 ms load dump events per ISO 7637-2. |
Use Scenario: Safeguarding CAN/LIN bus transceivers and analog sensor front-ends (e.g., pressure, temperature) in engine control units (ECUs). IC Role / Device Role / Timing Role: Line-side TVS on sensor supply or signal lines, referenced to vehicle ground, suppressing ESD (±15 kV contact) and coupled transients. Use Value: Maintains signal integrity and prevents latch-up in transceivers by clamping sub-100 ns ESD events to <126 V while adding <0.5 pF capacitance. |
| Telecom Equipment Surge Suppression | Consumer Appliance Motor Control Protection |
|
Use Scenario: Shielding Ethernet PHY power pins and auxiliary bias rails in PoE-powered switches and base stations from lightning-induced surges. IC Role / Device Role / Timing Role: Primary-level TVS on 3.3 V/5 V/12 V bias rails, coordinated with secondary GDT or MOV stages. Use Value: Limits let-through energy to <10 mJ during 10/1000 µs surges, preserving PHY IC reliability without affecting 100 Mbps+ data integrity. |
Use Scenario: Guarding H-bridge gate drivers and MCU I/O in washing machine and HVAC fan motor controllers against back-EMF spikes. IC Role / Device Role / Timing Role: Unidirectional TVS on VDD rails and half-bridge source nodes, absorbing 600 W inductive energy bursts. Use Value: Eliminates need for external snubbers in cost-sensitive designs while maintaining >100,000-cycle surge endurance per IEC 61000-4-4. |
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-M3/52 | Halogen-free, RoHS-compliant variant; identical electrical specs and SMB package. | No difference in circuit function or layout; selected where halogen-free compliance is mandated (e.g., EU public infrastructure projects). | Choose when halogen-free material declaration is required; otherwise, SMBJ78A-E3/52 offers same performance at standard commercial grade. |
| SMBJ78AHE3_B/I | AEC-Q101 qualified version; same VWM, VBR, VC, and PPPM, but validated for automotive temperature cycling and lifetime reliability. | Required for under-hood or safety-critical automotive modules; not necessary for industrial or consumer use. | Select SMBJ78AHE3_B/I only for automotive OEM or Tier-1 designs requiring AEC-Q101 certification; SMBJ78A-E3/52 suffices for non-automotive applications. |
Compared with SMBJ78A-M3/52, the SMBJ78A-E3/52 provides identical surge protection performance with standard RoHS compliance, while SMBJ78AHE3_B/I adds automotive qualification at higher cost-making the E3 variant optimal for cost-sensitive industrial and telecom deployments where AEC-Q101 is not mandated.
Availability
SMBJ78A-E3/52 is available at Aetrix Electronics and suitable for industrial power supply protection, automotive sensor interface protection, and telecom equipment surge suppression requiring stable component supply, full traceability, and long-term lifecycle support.
Supply support for SMBJ78A-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, efficiency, and application-specific optimization.
The SMBJ series was developed for high-energy transient suppression in space-constrained surface-mount applications, targeting industrial automation, automotive electronics, and communications infrastructure where robustness and consistency are critical.
FAQ
What is the maximum clamping voltage of SMBJ78A-E3/52 and under what test condition?
The SMBJ78A-E3/52 has a maximum clamping voltage (VC) of 126 V, measured at a peak pulse current (IPPM) of 4.8 A using the standardized 10/1000 µs double-exponential waveform. This value defines the upper voltage limit imposed on protected circuits during surge events and is confirmed in the Vishay datasheet Document Number 88392, page 2.
Is SMBJ78A-E3/52 suitable for automotive applications?
The SMBJ78A-E3/52 is a commercial-grade, RoHS-compliant TVS diode and is not AEC-Q101 qualified. For automotive applications requiring qualification, Vishay offers the SMBJ78AHE3_B/I variant. The SMBJ78A-E3/52 may be used in non-safety-critical automotive subsystems (e.g., infotainment power rails) if customer validation confirms sufficient reliability-but SMBJ78AHE3_B/I is required for engine bay or ADAS-related designs.
What is the reverse leakage current specification for SMBJ78A-E3/52 at its stand-off voltage?
The SMBJ78A-E3/52 exhibits a maximum reverse leakage current (ID) of 1.0 µA at its stand-off voltage (VWM) of 78 V, tested at TA = 25 °C. This low leakage ensures minimal power loss in always-on systems and avoids false triggering in high-impedance sensing circuits protected by the SMBJ78A-E3/52.
Does SMBJ78A-E3/52 have bidirectional capability?
No, SMBJ78A-E3/52 is a unidirectional TVS diode, indicated by the "A" suffix and cathode band marking. Bidirectional variants use the "CA" suffix (e.g., SMBJ78CA). Using SMBJ78A-E3/52 in AC-coupled or symmetrical surge environments requires external design accommodations, as it conducts only in reverse bias and blocks forward current beyond ~3.5 V.
What is the thermal resistance and recommended PCB layout for SMBJ78A-E3/52?
The SMBJ78A-E3/52 has a typical junction-to-ambient thermal resistance (RθJA) of 100 °C/W, specified with 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal. To achieve rated 600 W pulse power, the PCB must implement these minimum pad dimensions and avoid excessive trace length or isolation that increases thermal impedance. The SMBJ78A-E3/52 datasheet Figure 2 provides derating curves for elevated ambient temperatures.
SMBJ78A-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:
- 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:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AA (SMBJ)
SMBJ78A-E3/52 FAQ
1.How can I place an order for SMBJ78A-E3/52 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ78A-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 SMBJ78A-E3/52 reliable?
The price and inventory of SMBJ78A-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 SMBJ78A-E3/52 is usually 5 days.
3.What payment methods are accepted for SMBJ78A-E3/52?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ78A-E3/52 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ78A-E3/52?
SMBJ78A-E3/52 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ78A-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 SMBJ78A-E3/52?
For technical support, including SMBJ78A-E3/52 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ78A-E3/52 requirements.
6.How does Aetrix verify that SMBJ78A-E3/52 is sourced from the original manufacturer or authorized distributors?
All SMBJ78A-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 SMBJ78A-E3/52 meets industry standards.
7.What is the process for return or replacement of SMBJ78A-E3/52?
All SMBJ78A-E3/52 units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ78A-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 SMBJ78A-E3/52 part is unused and in its original packaging.
Return procedure for SMBJ78A-E3/52:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ78A-E3/52 Tags
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