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

Vishay General Semiconductor - Diodes Division SA78-E3/54

Name: SA78-E3/54
Brand: Vishay General Semiconductor - Diodes Division
SKU: SA78-E3/54
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SA78-E3/54

Manufacturer:: Vishay General Semiconductor - Diodes Division

Category:: TVS Diodes

Package:: DO-204AC, DO-15, Axial

Datasheet:: SA78-E3/54.pdf

Description:: TVS DIODE 78VWM 139VC DO204AC

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Product details

Overview

SA78-E3/54 from Vishay General Semiconductor is a uni-directional Transient Voltage Suppressor (TVS) diode in DO-204AC (DO-15) package, designed for clamping voltage transients on power and signal lines. It features a 78 V stand-off voltage (V_WM), 86.7–95.8 V breakdown voltage (V_BR) at 1.0 mA, 500 W peak pulse power (10/1000 µs), 126 V maximum clamping voltage at 4 A peak pulse current, and operates from –55 °C to +175 °C junction temperature.

For engineers reviewing the SA78-E3/54 datasheet, SA78-E3/54 pinout, SA78-E3/54 application, or SA78-E3/54 equivalent, this device is selected for robust overvoltage protection in automotive power rails, industrial sensor interfaces, and DC input stages where fast response (<1 ns), low clamping ratio, and AEC-Q101 qualification are required.

Technical Context

The SA78-E3/54 implements a glass-passivated silicon p-n junction optimized for transient suppression under repetitive 10/1000 µs surge waveforms. Its unidirectional polarity uses a cathode band marking and delivers 3.5 V max forward voltage at 100 A, with 70 A non-repetitive forward surge rating (8.3 ms half-sine).

It complies with AEC-Q101 stress testing for automotive use and meets UL 94 V-0 flammability requirements via its molded epoxy DO-204AC case. The device exhibits a +0.065 %/°C temperature coefficient of breakdown voltage and maintains stable clamping performance up to 175 °C junction temperature.

Key Specifications

Parameter	Value and Actual Design Meaning
V_WM	78 V - Maximum continuous reverse operating voltage before clamping begins
V_BR (min/max)	86.7 V / 95.8 V at 1.0 mA - Ensures reliable turn-on above normal operating rail while avoiding false triggering
V_C @ I_PPM	126 V at 4 A - Limits downstream voltage stress during 10/1000 µs transients
P_PPM	500 W - Sustains high-energy surges common in automotive load-dump and inductive switching events
I_F_SM	70 A - Withstands short-duration forward surge currents without degradation
T_J range	–55 °C to +175 °C - Enables deployment in under-hood automotive and industrial environments
Leakage I_D	1.0 µA max at V_WM - Minimizes standby power loss in battery-powered systems

Pinout & Package

Package: DO-204AC (DO-15), axial-leaded, epoxy-molded case with matte tin-plated leads compliant to J-STD-002 and JESD 22-B102 solderability standards. Cathode identified by color band.

Pin/Terminal	Circuit Role	Design Meaning
Anode	Forward current entry / transient return path	Connected to lower-potential side (e.g., ground or return rail) in uni-directional clamp configuration
Cathode	Clamping node / protected line connection	Connected to the line being protected (e.g., 24 V supply rail); color band marks this end

Key Features

Feature	Design Value
Glass-passivated junction	Enables stable, repeatable breakdown behavior and long-term reliability under thermal cycling
AEC-Q101 qualification	Validated for automotive applications including engine control units and body electronics
500 W peak pulse power (10/1000 µs)	Handles ISO 7637-2 Pulse 5a load-dump energy without failure
Low incremental clamping resistance	Ensures minimal voltage overshoot during fast-rising transients (e.g., ESD, relay bounce)
UL 94 V-0 molding compound	Meets flame-retardancy requirements for enclosed industrial and transportation equipment

Applications

Automotive Power Rail Protection	Industrial Sensor Interface Protection
Use Scenario: Protecting 24 V supply inputs in engine control modules against load-dump transients per ISO 7637-2. IC Role / Device Role / Timing Role: Uni-directional TVS clamping element placed between power rail and chassis ground. Use Value: Limits transient voltage to ≤126 V, preventing damage to downstream DC-DC converters and microcontrollers rated for 36 V absolute max.	Use Scenario: Shielding analog output lines (e.g., 4–20 mA current loop) from ESD and inductive coupling in factory automation sensors. IC Role / Device Role / Timing Role: Low-leakage (≤1 µA) clamping diode connected across signal and return lines. Use Value: Maintains signal integrity with <1 ns response time and no DC loading due to sub-µA reverse leakage at 78 V.
Telecom DC Power Input Stage	Consumer Appliance Motor Drive Protection
Use Scenario: Safeguarding primary-side 48 V DC input of PoE-powered network switches from lightning-induced surges. IC Role / Device Role / Timing Role: First-line transient suppressor mounted at board edge before bulk capacitance and upstream regulator. Use Value: Absorbs 500 W pulses without derating at ambient temperatures up to 85 °C, supporting EN 61000-4-5 compliance.	Use Scenario: Suppressing back-EMF spikes generated by brushed DC motors in smart home appliances (e.g., vacuum cleaners, washing machines). IC Role / Device Role / Timing Role: Flyback clamp across motor terminals, conducting only during inductive turn-off events. Use Value: Withstands 70 A surge current (8.3 ms half-sine), eliminating need for external snubbers and reducing BOM count.

Automotive Power Rail Protection

Industrial Sensor Interface Protection

Use Scenario: Protecting 24 V supply inputs in engine control modules against load-dump transients per ISO 7637-2.

IC Role / Device Role / Timing Role: Uni-directional TVS clamping element placed between power rail and chassis ground.

Use Value: Limits transient voltage to ≤126 V, preventing damage to downstream DC-DC converters and microcontrollers rated for 36 V absolute max.

Use Scenario: Shielding analog output lines (e.g., 4–20 mA current loop) from ESD and inductive coupling in factory automation sensors.

IC Role / Device Role / Timing Role: Low-leakage (≤1 µA) clamping diode connected across signal and return lines.

Use Value: Maintains signal integrity with <1 ns response time and no DC loading due to sub-µA reverse leakage at 78 V.

Telecom DC Power Input Stage

Consumer Appliance Motor Drive Protection

Use Scenario: Safeguarding primary-side 48 V DC input of PoE-powered network switches from lightning-induced surges.

IC Role / Device Role / Timing Role: First-line transient suppressor mounted at board edge before bulk capacitance and upstream regulator.

Use Value: Absorbs 500 W pulses without derating at ambient temperatures up to 85 °C, supporting EN 61000-4-5 compliance.

Use Scenario: Suppressing back-EMF spikes generated by brushed DC motors in smart home appliances (e.g., vacuum cleaners, washing machines).

IC Role / Device Role / Timing Role: Flyback clamp across motor terminals, conducting only during inductive turn-off events.

Use Value: Withstands 70 A surge current (8.3 ms half-sine), eliminating need for external snubbers and reducing BOM count.

Equivalent & Alternatives

The following parts are listed as comparable options for similar transient voltage suppression applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
SMAJ78A-E3/5A	Same V_WM (78 V), but SMA package (DO-214AC); 400 W P_PPM; 137 V V_C @ 3.6 A	Surface-mount footprint; lower power rating; higher clamping voltage	Select for space-constrained PCBs where reflow compatibility and automated assembly are prioritized over peak surge margin.
1.5KE78A	Same V_WM/V_BR range, but DO-201 package; 1500 W P_PPM; 124 V V_C @ 12.1 A	Higher surge capacity; larger axial package; not AEC-Q101 qualified	Select for industrial mains-input protection where ultimate energy handling outweighs automotive qualification needs.

Compared with SMAJ78A-E3/5A and 1.5KE78A, the SA78-E3/54 offers AEC-Q101 qualification and optimal balance of clamping voltage (126 V), surge rating (500 W), and DO-15 through-hole manufacturability-making it preferred for automotive and high-reliability industrial designs requiring proven qualification and ease of manual or wave-solder rework.

Availability

SA78-E3/54 is available at Aetrix Electronics and suitable for automotive power rail protection, industrial sensor interface protection, and telecom DC power input stage applications requiring stable component supply, full traceability, and lifecycle continuity.

Supply support for SA78-E3/54 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 passive components with emphasis on reliability, power handling, and automotive-grade qualification.

The SAxxA series is part of Vishay's TRANSZORB® TVS family, engineered specifically for robust, standardized transient suppression in harsh environments-including automotive, industrial, and telecom infrastructure-where predictable clamping, low leakage, and AEC-Q101 validation are mandatory.

FAQ

What is the breakdown voltage range of the SA78-E3/54?

The SA78-E3/54 has a specified breakdown voltage (V_BR) range of 86.7 V to 95.8 V at a test current of 1.0 mA. This range ensures consistent turn-on behavior across production lots while accommodating process variation. The value is measured per ANSI/IEEE C62.35 and directly determines the minimum overvoltage threshold at which the SA78-E3/54 begins clamping.

Is the SA78-E3/54 suitable for automotive applications?

Yes, the SA78-E3/54 is AEC-Q101 qualified and explicitly rated for automotive use. Its construction-glass-passivated junction, DO-204AC package with UL 94 V-0 epoxy, and operation up to +175 °C junction temperature-meets stress-test requirements for engine bay and chassis-mounted electronics. The SA78-E3/54 is commonly deployed in 24 V system protection per ISO 7637-2.

What is the maximum clamping voltage of the SA78-E3/54 under surge conditions?

The SA78-E3/54 exhibits a maximum clamping voltage (V_C) of 126 V when subjected to its rated peak pulse current of 4 A using the standard 10/1000 µs waveform. This value defines the highest voltage seen by downstream circuitry during a worst-case transient and is critical for ensuring compatibility with the absolute maximum ratings of protected ICs and regulators.

Does the SA78-E3/54 have polarity marking, and how is it identified?

Yes, the SA78-E3/54 is a uni-directional TVS diode and features a visible cathode band (color band) on the package body. This band identifies the cathode terminal, which must be connected toward the line being protected (e.g., positive supply rail), while the anode connects to ground or return. No marking is used for bi-directional variants-but SA78-E3/54 is explicitly uni-directional per its "A" suffix and datasheet designation.

What is the peak pulse power rating of the SA78-E3/54, and what waveform does it reference?

SA78-E3/54 is rated for 500 W peak pulse power (P_PPM) using the industry-standard 10/1000 µs double-exponential waveform defined by R.E.A. This rating reflects its ability to absorb transient energy from sources such as inductive switching, load dump, or lightning-induced surges without failure-provided duty cycle remains ≤0.01 % as specified in the Vishay datasheet 88378.

SA78-E3/54 Specifications

Product attributes: Attribute value

Manufacturer:: Vishay General Semiconductor - Diodes Division

Package/Case:: DO-204AC, DO-15, Axial

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):: 3.6A

Power - Peak Pulse:: 500W

Power Line Protection:: No

Applications:: General Purpose

Capacitance @ Frequency:: -

Operating Temperature:: -55°C ~ 175°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: DO-204AC (DO-15)

SA78-E3/54 FAQ

1.How can I place an order for SA78-E3/54 through Aetrix?

Please submit a Request for Quotation (RFQ) for SA78-E3/54 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 SA78-E3/54 reliable?

The price and inventory of SA78-E3/54 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SA78-E3/54 is usually 5 days.

3.What payment methods are accepted for SA78-E3/54?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SA78-E3/54 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SA78-E3/54?

SA78-E3/54 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SA78-E3/54 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 SA78-E3/54?

For technical support, including SA78-E3/54 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SA78-E3/54 requirements.

6.How does Aetrix verify that SA78-E3/54 is sourced from the original manufacturer or authorized distributors?

All SA78-E3/54 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 SA78-E3/54 meets industry standards.

7.What is the process for return or replacement of SA78-E3/54?

All SA78-E3/54 units undergo pre-shipment inspection (PSI). If there is an issue with SA78-E3/54, 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 SA78-E3/54 part is unused and in its original packaging.

Return procedure for SA78-E3/54:

1.Submit a request within 90 days.

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

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