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Vishay General Semiconductor - Diodes Division SMBJ78-E3/5B
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- Part No.:
- SMBJ78-E3/5B
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ78-E3/5B.pdf
- Description:
- TVS DIODE 78VWM 139VC DO214AA
- Quantity:
- Payment:
- Shipping:
Inventory:2,665
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Product details
Overview
SMBJ78-E3/5B 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 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, 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-E3/5B datasheet, SMBJ78-E3/5B pinout, SMBJ78-E3/5B application, or SMBJ78-E3/5B equivalent, key selection criteria include its unidirectional polarity, 1.0 µA max reverse leakage at VWM, 150 °C max junction temperature, and RoHS-compliant matte tin-plated leads suitable for automated SMT assembly.
Technical Context
This TVS diode operates as a silicon avalanche clamp, responding within <1 ps to transient overvoltages and limiting voltage excursions to ≤126 V during 4.8 A 10/1000 µs surges. Its glass-passivated junction ensures stable breakdown characteristics and low incremental surge resistance.
The device is rated for 5.0 W steady-state power dissipation on infinite heatsink at 50 °C ambient, with thermal resistance of 100 °C/W (junction-to-ambient) and 20 °C/W (junction-to-lead), enabling reliable operation in compact PCB layouts without forced cooling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM (Stand-off) | 78 V - Maximum continuous reverse operating voltage before conduction begins |
| VBR (Breakdown) | 86.7–95.8 V at 1 mA - Confirmed avalanche onset range defining clamping threshold |
| VC (Clamping) | 126 V at IPPM = 4.8 A - Peak voltage seen by protected circuit during worst-case surge |
| PPPM | 600 W - Surge energy handling capacity under standardized 10/1000 µs waveform |
| IPPM | 4.8 A - Maximum non-repetitive peak pulse current the device safely conducts |
| TJ max. | +150 °C - Maximum junction temperature enabling use in high-ambient industrial environments |
| Leakage (ID) | ≤1.0 µA at 78 V - Minimal standby power loss and negligible loading on source circuits |
Pinout & Package
Package: SMB (DO-214AA), surface-mount, low-profile case with matte tin-plated leads solderable per J-STD-002 and JESD 22-B102. Cathode indicated by band marking on body.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry point during forward conduction | Connected to lower-potential side (e.g., ground or return path) in unidirectional protection configuration |
| Cathode | Current exit point during forward conduction; marked end | Connected to protected line (e.g., +78 V rail); clamps transients toward anode when voltage exceeds VBR |
Key Features
| Feature | Design Value |
|---|---|
| 600 W peak pulse power | Enables robust protection against IEC 61000-4-5 Level 4 surges (4 kV/2 Ω) on 24–48 V systems |
| Low incremental surge resistance | Minimizes VC overshoot during fast-rising transients, improving clamping precision |
| MSL Level 1 (260 °C peak) | Supports lead-free reflow without preconditioning; compatible with standard SMT assembly lines |
| Glass passivated junction | Ensures long-term stability of VBR and leakage performance across temperature and life cycles |
| RoHS-compliant, commercial grade | E3 suffix confirms compliance with EU RoHS Directive 2011/65/EU and JEDEC JESD201 Class 2 whisker resistance |
Applications
| Industrial PLC I/O Protection | Automotive Body Control Module (BCM) Power Rails |
|---|---|
|
Use Scenario: Protecting 24 V digital input channels from inductive kickback caused by relay/solenoid switching. IC Role / Device Role / Timing Role: Unidirectional TVS placed between input line and ground to clamp positive transients above 78 V. Use Value: Limits voltage to ≤126 V during 4.8 A surges, preventing damage to downstream optocouplers and microcontroller GPIOs. |
Use Scenario: Safeguarding 12 V supply lines feeding microcontrollers and CAN transceivers in BCMs. IC Role / Device Role / Timing Role: Standoff-rated TVS absorbing load-dump and jump-start transients on battery-connected rails. Use Value: Withstands 600 W pulses without degradation, maintaining system uptime during automotive electrical disturbances. |
| Telecom PoE Midspan Injector Ports | Consumer Appliance Motor Drive Power Stages |
|
Use Scenario: Protecting 48 V DC power pairs in IEEE 802.3af/at midspan injectors from ESD and lightning-induced surges. IC Role / Device Role / Timing Role: Unidirectional clamp referenced to common-mode ground, suppressing differential-mode overvoltage events. Use Value: 1.0 µA leakage at 78 V avoids unnecessary power drain on always-on PoE detection circuitry. |
Use Scenario: Shielding H-bridge gate drivers and MCU power rails from back-EMF spikes generated by brushed DC motors. IC Role / Device Role / Timing Role: Fast-response avalanche diode placed across motor supply terminals to shunt inductive energy. Use Value: Sub-nanosecond response time ensures clamping initiates before driver ICs experience overvoltage stress. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ78A-M3/5B | Halogen-free, RoHS-compliant variant; identical electrical specs and SMB package | No functional difference; selected where halogen-free material compliance is mandated | Choose M3 suffix when meeting IPC-1752A halogen-free reporting requirements |
| SMBJ78AHE3_B/I | AEC-Q101 qualified version; same VWM/VC/PPPM, but validated for automotive temperature cycling and lifetime reliability | Required for under-hood or safety-critical automotive modules; not necessary for commercial-grade equipment | Select HE3 suffix only when automotive qualification (e.g., ISO/TS 16949 production) is contractually required |
Compared with SMBJ78-E3/5B, the M3/5B offers identical protection performance with halogen-free molding compound, while the HE3_B/I adds AEC-Q101 validation for automotive deployment - neither is pin-compatible drop-in replacements unless explicitly specified in design documentation, and all require verification of thermal layout and surge test compliance.
Availability
SMBJ78-E3/5B is available at Aetrix Electronics and suitable for industrial automation, telecom infrastructure, and consumer appliance designs requiring stable component supply, consistent RoHS compliance, and proven surge immunity in SMB footprint.
Supply support for SMBJ78-E3/5B 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, MOSFETs, and protection devices with emphasis on reliability, efficiency, and manufacturability.
The SMBJ series targets board-level transient suppression in space-constrained applications, delivering high-power surge handling in the industry-standard SMB package for cost-effective, high-yield SMT integration.
FAQ
What is the maximum clamping voltage of SMBJ78-E3/5B at its rated peak pulse current?
The SMBJ78-E3/5B has a maximum clamping voltage (VC) of 126 V when subjected to its rated peak pulse current of 4.8 A using the 10/1000 µs waveform. This value is measured per ANSI/IEEE C62.35 and defines the upper voltage limit imposed on protected circuitry during surge events - critical for ensuring downstream components remain within their absolute maximum ratings.
Is SMBJ78-E3/5B suitable for bidirectional transient suppression?
No, SMBJ78-E3/5B is a unidirectional TVS diode, as indicated by the "A" suffix and cathode band marking. For bidirectional protection, Vishay specifies the "CA" suffix (e.g., SMBJ78CA). Using SMBJ78-E3/5B in bidirectional applications would result in forward conduction during negative transients, potentially causing failure or unintended circuit behavior.
What does the "E3/5B" suffix mean in SMBJ78-E3/5B?
The "E3" denotes RoHS-compliant, commercial-grade construction with matte tin-plated leads; "5B" specifies packaging in 13-inch diameter plastic tape and reel with 3200 units per reel. This ordering code aligns with Vishay's standardized nomenclature for environmental compliance and logistics - distinct from M3 (halogen-free) or HE3 (AEC-Q101 qualified) variants.
Can SMBJ78-E3/5B be used in automotive applications?
SMBJ78-E3/5B is commercial-grade and not AEC-Q101 qualified. For automotive use, Vishay offers the SMBJ78AHE3_B/I variant, which undergoes extended temperature cycling, humidity testing, and lifetime validation per AEC-Q101. Deploying SMBJ78-E3/5B in automotive systems may violate OEM qualification requirements and void warranty coverage.
What is the thermal resistance of SMBJ78-E3/5B, and how does it affect PCB layout?
SMBJ78-E3/5B has a typical junction-to-ambient thermal resistance (RθJA) of 100 °C/W and junction-to-lead (RθJL) of 20 °C/W. To maintain safe junction temperatures below 150 °C, PCB copper pad area must follow Vishay's recommended 0.2" × 0.2" (5.0 mm × 5.0 mm) per terminal - undersized pads increase thermal impedance and risk premature thermal runaway during repetitive surges.
SMBJ78-E3/5B Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AA, SMB
- Series:
- TransZorb®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- 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-E3/5B FAQ
1.How can I place an order for SMBJ78-E3/5B through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ78-E3/5B 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 SMBJ78-E3/5B reliable?
The price and inventory of SMBJ78-E3/5B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ78-E3/5B is usually 5 days.
3.What payment methods are accepted for SMBJ78-E3/5B?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ78-E3/5B transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ78-E3/5B?
SMBJ78-E3/5B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ78-E3/5B 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 SMBJ78-E3/5B?
For technical support, including SMBJ78-E3/5B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ78-E3/5B requirements.
6.How does Aetrix verify that SMBJ78-E3/5B is sourced from the original manufacturer or authorized distributors?
All SMBJ78-E3/5B 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 SMBJ78-E3/5B meets industry standards.
7.What is the process for return or replacement of SMBJ78-E3/5B?
All SMBJ78-E3/5B units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ78-E3/5B, 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 SMBJ78-E3/5B part is unused and in its original packaging.
Return procedure for SMBJ78-E3/5B:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ78-E3/5B Tags
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