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Home > Products > Circuit Protection > Transient Voltage Suppressors (TVS) > TVS Diodes

Vishay General Semiconductor - Diodes Division SMBG78A-E3/5B

Name: SMBG78A-E3/5B
Brand: Vishay General Semiconductor - Diodes Division
SKU: SMBG78A-E3/5B
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SMBG78A-E3/5B

Manufacturer:: Vishay General Semiconductor - Diodes Division

Category:: TVS Diodes

Package:: DO-215AA, SMB Gull Wing

Datasheet:: SMBG78A-E3/5B.pdf

Description:: TVS DIODE 78VWM 126VC DO215AA

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Product details

Overview

SMBG78A-E3/5B from Vishay General Semiconductor is a unidirectional surface-mount TransZORB® transient voltage suppressor (TVS) diode designed for robust overvoltage protection in power and signal lines. It features a 78 V stand-off voltage (V_WM), 86.7–95.8 V breakdown voltage (V_BR) at 1 mA, 126 V maximum clamping voltage (V_C) at 4.8 A peak pulse current, and 600 W peak pulse power rating with 10/1000 µs waveform - deployed in automotive power electronics, industrial motor drives, and DC bus protection.

For engineers reviewing the SMBG78A-E3/5B datasheet, SMBG78A-E3/5B pinout, SMBG78A-E3/5B application, or SMBG78A-E3/5B equivalent, key selection criteria include its AEC-Q101 qualification, DO-215AA (SMBG) package compatibility, unidirectional polarity with cathode band marking, and thermal resistance (R_θJA = 100 °C/W) under standard PCB pad layout.

Technical Context

This TVS diode operates as a voltage-clamping surge protector, responding within picoseconds to transients induced by inductive switching or ESD events. Its glass-passivated junction ensures stable breakdown behavior and low leakage (<1.0 µA at V_WM), while the unidirectional configuration enables integration into DC-biased circuits without reverse conduction path concerns.

The device is rated for repetitive 10/1000 µs surges at 0.01% duty cycle and supports peak forward surge current (I_FSM) up to 100 A (8.3 ms half-sine), making it suitable for high-energy transient suppression in 24 V and 48 V industrial systems where sustained overvoltage immunity is critical.

Key Specifications

Parameter	Value and Actual Design Meaning
V_WM	78 V - Maximum continuous reverse operating voltage before clamping begins; defines safe DC bias margin in protected line.
V_BR (min/max)	86.7 V / 95.8 V at I_T = 1 mA - Confirmed breakdown range ensures predictable turn-on threshold across production lot.
V_C @ I_PPM	126 V at 4.8 A - Clamping voltage limits downstream component stress during 600 W transient events.
P_PPM	600 W - Peak pulse power handling capability with standardized 10/1000 µs waveform per ANSI/IEEE C62.35.
I_FSM	100 A - Single half-sine surge current rating (8.3 ms), supporting high-energy fault conditions in power rails.
T_J max	+150 °C - Maximum junction temperature enabling operation in under-hood automotive and enclosed industrial environments.
R_θJA	100 °C/W - Thermal resistance from junction to ambient on 0.2" × 0.2" copper pads; informs heatsinking requirements.

Pinout & Package

Package: SMBG (DO-215AA) - surface-mount, low-profile gull-wing leaded package with matte tin-plated terminals, MSL Level 1 (260 °C peak reflow), UL 94 V-0 molding compound, and AEC-Q101 qualification.

Pin/Terminal	Circuit Role	Design Meaning
Cathode (banded end)	High-side connection point for unidirectional clamping	Connected to protected line; conducts surge current to ground when V_LINE exceeds V_BR.
Anode	Reference/ground return path	Typically tied to system ground plane; completes clamping loop during transient events.

Key Features

Feature	Design Value
AEC-Q101 qualified	Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD testing per JESD22 standards.
Glass passivated junction	Ensures stable V_BR tolerance and low leakage drift over time and temperature in harsh environments.
600 W peak pulse power	Provides robust protection against ISO 7637-2 Pulse 1/2a/5a and IEC 61000-4-5 surge waveforms in 24 V/48 V systems.
Low incremental surge resistance	Minimizes V_C overshoot during fast-rising transients, improving clamping precision for sensitive ICs.
RoHS-compliant, halogen-free option available	E3 suffix denotes industrial-grade RoHS compliance; M3 suffix adds halogen-free material compliance.

Applications

Automotive Power Distribution	Industrial Motor Drive Control
Use Scenario: Protection of 24 V battery-fed ECUs, body control modules, and lighting drivers against load dump and alternator ripple. IC Role / Device Role / Timing Role: Unidirectional TVS placed between power rail and chassis ground to clamp transients above 78 V. Use Value: Prevents latch-up or permanent damage to microcontrollers and gate drivers during ISO 16750-2 load dump events (up to 120 V).	Use Scenario: Surge suppression on gate drive supply lines and feedback sensing paths in variable-frequency drives. IC Role / Device Role / Timing Role: Standoff-rated TVS absorbing inductive kickback from IGBT/MOSFET switching noise. Use Value: Maintains signal integrity on analog current-sense inputs by limiting voltage excursions to ≤126 V during 4.8 A transients.
Telecom DC Power Feeds	Renewable Energy Inverter DC Link
Use Scenario: Overvoltage protection on -48 V telecom rectifier outputs exposed to lightning-induced surges. IC Role / Device Role / Timing Role: Primary clamping device on DC input bus upstream of DC/DC converters. Use Value: Withstands 600 W pulses without degradation, meeting Telcordia GR-1089-CORE Level 3 surge immunity requirements.	Use Scenario: Protection of photovoltaic string combiner box DC inputs against lightning-induced transients. IC Role / Device Role / Timing Role: Unidirectional TVS connected between PV+ and ground to shunt surge energy away from MPPT controller. Use Value: 150 °C max junction temperature supports operation in outdoor enclosures with minimal airflow or heatsinking.

Automotive Power Distribution

Industrial Motor Drive Control

Use Scenario: Protection of 24 V battery-fed ECUs, body control modules, and lighting drivers against load dump and alternator ripple.

IC Role / Device Role / Timing Role: Unidirectional TVS placed between power rail and chassis ground to clamp transients above 78 V.

Use Value: Prevents latch-up or permanent damage to microcontrollers and gate drivers during ISO 16750-2 load dump events (up to 120 V).

Use Scenario: Surge suppression on gate drive supply lines and feedback sensing paths in variable-frequency drives.

IC Role / Device Role / Timing Role: Standoff-rated TVS absorbing inductive kickback from IGBT/MOSFET switching noise.

Use Value: Maintains signal integrity on analog current-sense inputs by limiting voltage excursions to ≤126 V during 4.8 A transients.

Telecom DC Power Feeds

Renewable Energy Inverter DC Link

Use Scenario: Overvoltage protection on -48 V telecom rectifier outputs exposed to lightning-induced surges.

IC Role / Device Role / Timing Role: Primary clamping device on DC input bus upstream of DC/DC converters.

Use Value: Withstands 600 W pulses without degradation, meeting Telcordia GR-1089-CORE Level 3 surge immunity requirements.

Use Scenario: Protection of photovoltaic string combiner box DC inputs against lightning-induced transients.

IC Role / Device Role / Timing Role: Unidirectional TVS connected between PV+ and ground to shunt surge energy away from MPPT controller.

Use Value: 150 °C max junction temperature supports operation in outdoor enclosures with minimal airflow or heatsinking.

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-E3/5B	Same V_WM (78 V), but lower P_PPM = 600 W (same rating), higher V_C = 127 V at 4.8 A; SMBJ package (DO-214AA) has larger footprint and higher R_θJA (110 °C/W).	Less suitable for space-constrained AEC-Q101 designs due to larger outline and reduced thermal performance.	Select SMBG78A-E3/5B when board area is limited and AEC-Q101 compliance is mandatory.
SMCJ78A-E3/5B	Same V_WM/V_BR, but P_PPM = 1500 W and V_C = 127 V at 11.8 A; SMC package (DO-214AB) offers higher surge capacity but larger size and no AEC-Q101 qualification.	Better for non-automotive 1500 W surge requirements; not validated for automotive temperature cycling or humidity testing.	Choose SMBG78A-E3/5B for automotive or thermally constrained 600 W applications; use SMCJ78A-E3/5B only if higher pulse energy is required and AEC-Q101 is not needed.

Compared with SMBJ78A-E3/5B and SMCJ78A-E3/5B, SMBG78A-E3/5B uniquely balances AEC-Q101 qualification, compact DO-215AA footprint, and precise 78 V standoff in a 600 W TVS - making it optimal for automotive and space-limited industrial designs requiring certified reliability.

Availability

SMBG78A-E3/5B is available at Aetrix Electronics and suitable for automotive electronics, industrial motor controls, and telecom power systems requiring stable component supply, long-term lifecycle support, and AEC-Q101-compliant surge protection.

Supply support for SMBG78A-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 application-specific optimization.

The SMBG TransZORB® series is engineered for high-reliability transient suppression in automotive, industrial, and telecom infrastructure - delivering consistent clamping performance, AEC-Q101 validation, and robust thermal design in compact surface-mount packages.

FAQ

What is the maximum clamping voltage of SMBG78A-E3/5B at its rated peak pulse current?

The SMBG78A-E3/5B has a maximum clamping voltage (V_C) of 126 V at its specified peak pulse current (I_PPM) of 4.8 A, measured using the 10/1000 µs waveform. This value defines the upper voltage limit imposed on protected circuitry during a 600 W transient event and is confirmed in the Vishay datasheet revision 09-Jan-2024, page 2. The SMBG78A-E3/5B maintains this clamping performance across its operational temperature range.

Is SMBG78A-E3/5B qualified for automotive applications?

Yes, SMBG78A-E3/5B is AEC-Q101 qualified, as explicitly stated in the Vishay datasheet (page 1, "MECHANICAL DATA" section and footnote 1 on page 3). This qualification covers stress tests including temperature cycling, high-temperature reverse bias, and ESD, confirming suitability for under-hood and body electronics. The SMBG78A-E3/5B meets automotive reliability requirements without derating in standard mounting conditions.

What does the 'E3/5B' suffix indicate in SMBG78A-E3/5B?

The 'E3' suffix denotes RoHS-compliant, industrial-grade construction with matte tin-plated leads; '5B' specifies packaging in 13-inch diameter plastic tape and reel with a base quantity of 3200 units. This differs from '52' (7-inch reel, 750 units). The SMBG78A-E3/5B is not halogen-free (that requires 'M3'), nor AEC-Q101-qualified (which requires 'HE3' or 'HM3'); however, the base SMBG78A device itself is AEC-Q101 qualified per datasheet note (1).

How does SMBG78A-E3/5B differ from bidirectional TVS diodes like SMBG78CA?

SMBG78A-E3/5B is unidirectional and features a cathode band for polarity identification, allowing use only in DC-biased circuits where reverse conduction must be blocked. In contrast, SMBG78CA is bidirectional with no polarity marking and symmetric clamping in both directions - suited for AC lines or differential signal protection. The SMBG78A-E3/5B's unidirectional structure yields lower leakage and tighter V_BR tolerance than its bidirectional counterpart.

What is the thermal resistance of SMBG78A-E3/5B, and how does it affect PCB layout?

The SMBG78A-E3/5B has a typical junction-to-ambient thermal resistance (R_θJA) of 100 °C/W when mounted on 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal, as specified in the Vishay datasheet (page 3, "THERMAL CHARACTERISTICS"). To maintain safe junction temperatures during repetitive surges, designers must provide adequate copper area and avoid excessive trace length; reducing pad size increases R_θJA and risks thermal runaway. The SMBG78A-E3/5B's thermal performance is optimized for standard SMBG footprint layouts.

SMBG78A-E3/5B Specifications

Product attributes: Attribute value

Manufacturer:: Vishay General Semiconductor - Diodes Division

Package/Case:: DO-215AA, SMB Gull Wing

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 (SMBG)

SMBG78A-E3/5B FAQ

1.How can I place an order for SMBG78A-E3/5B through Aetrix?

Please submit a Request for Quotation (RFQ) for SMBG78A-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 SMBG78A-E3/5B reliable?

The price and inventory of SMBG78A-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 SMBG78A-E3/5B is usually 5 days.

3.What payment methods are accepted for SMBG78A-E3/5B?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBG78A-E3/5B transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SMBG78A-E3/5B?

SMBG78A-E3/5B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SMBG78A-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 SMBG78A-E3/5B?

For technical support, including SMBG78A-E3/5B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBG78A-E3/5B requirements.

6.How does Aetrix verify that SMBG78A-E3/5B is sourced from the original manufacturer or authorized distributors?

All SMBG78A-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 SMBG78A-E3/5B meets industry standards.

7.What is the process for return or replacement of SMBG78A-E3/5B?

All SMBG78A-E3/5B units undergo pre-shipment inspection (PSI). If there is an issue with SMBG78A-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 SMBG78A-E3/5B part is unused and in its original packaging.

Return procedure for SMBG78A-E3/5B:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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