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Vishay General Semiconductor - Diodes Division SA78-E3/73
- Part No.:
- SA78-E3/73
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-204AC, DO-15, Axial
- Datasheet:
-
SA78-E3/73.pdf
- Description:
- TVS DIODE 78VWM 139VC DO204AC
- Quantity:
- Payment:
- Shipping:
Inventory:2,217
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Product details
Overview
SA78-E3/73 from Vishay General Semiconductor is a unidirectional Transient Voltage Suppressor (TVS) diode in DO-204AC (DO-15) package, designed for primary overvoltage protection of DC power rails and signal lines. It features 78 V stand-off voltage (VWM), 86.7–95.8 V breakdown voltage (VBR) at 1 mA, 500 W peak pulse power (10/1000 µs), clamping voltage of 126 V at 4 A peak pulse current, and operates across –55 °C to +175 °C junction temperature.
For engineers reviewing the SA78-E3/73 datasheet, SA78-E3/73 pinout, SA78-E3/73 application, or SA78-E3/73 equivalent, this part serves as a robust, AEC-Q101-qualified transient suppressor for automotive power supply inputs, industrial sensor interfaces, and MOSFET gate protection where fast response (<1 ns), low clamping ratio, and high surge robustness are required.
Technical Context
This unidirectional TVS diode uses a glass-passivated silicon junction to achieve stable avalanche breakdown with low incremental surge resistance and excellent clamping linearity under repetitive 10/1000 µs transients. Its 3.0 W steady-state power dissipation supports continuous operation on PCB traces without heatsinking when lead temperature is maintained ≤75 °C.
The device exhibits a +0.07 %/°C temperature coefficient of breakdown voltage and maintains <1.0 µA reverse leakage at rated VWM, enabling reliable protection in low-power sensor circuits. Polarity is marked by a cathode band, and it complies with JESD22-B102 solderability and JESD201 Class 1A whisker resistance requirements.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 78 V - Maximum continuous reverse operating voltage before significant leakage; defines safe DC rail margin for 72–80 V systems. |
| VBR (min/max) | 86.7 V / 95.8 V at 1 mA - Confirmed avalanche onset range; ensures predictable turn-on during transients without premature conduction. |
| VC @ IPPM | 126 V at 4 A - Clamped voltage during full-rated 500 W surge; limits downstream IC stress to ≤126 V under worst-case 10/1000 µs event. |
| PPPM | 500 W - Peak pulse power handling per 10/1000 µs waveform; supports IEC 61000-4-5 Level 4 surge immunity testing. |
| IFSM | 70 A - Non-repetitive forward surge rating (10 ms half-sine); enables robustness against accidental polarity reversal or inrush events. |
| TJ max | +175 °C - Maximum junction temperature; allows operation in under-hood automotive or high-ambient industrial environments. |
| Package | DO-204AC (DO-15) - Standard axial-leaded through-hole package with UL 94 V-0 molded epoxy; compatible with legacy wave-solder processes. |
Pinout & Package
SA78-E3/73 is a two-terminal unidirectional TVS diode in DO-204AC (DO-15) package. The cathode is marked by a color band on the body; the anode is the unmarked end. Leads are matte tin-plated and compliant with J-STD-002 solderability standards.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward current entry / transient return path | Connected to system ground or low-side reference; completes clamping loop during positive transients on cathode side. |
| Cathode | Protected line connection / transient sensing node | Connected to the line being protected (e.g., 78 V rail input); avalanche conduction begins here when voltage exceeds VBR. |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated chip junction | Ensures long-term stability of VBR and leakage performance across thermal cycling and humidity exposure. |
| 500 W peak pulse power (10/1000 µs) | Supports repeated surge events per IEC 61000-4-5 without parameter shift or degradation. |
| AEC-Q101 qualified | Validated for automotive powertrain and chassis applications requiring zero defect reliability and extended temperature operation. |
| Low clamping ratio (VC/VBR ≈ 1.33) | Minimizes voltage overshoot during clamping-critical for protecting 100 V-rated MOSFETs and wide-VDS drivers. |
| JESD201 Class 1A whisker resistance | Prevents tin whisker growth under thermal stress, ensuring long-term solder joint integrity in high-reliability assemblies. |
Applications
| Automotive Power Input Protection | Industrial Sensor Signal Line Protection |
|---|---|
|
Use Scenario: Protecting 72–80 V battery-fed ECUs and ADAS control units from load dump and alternator transients. IC Role / Device Role / Timing Role: Primary clamping element placed between battery rail and upstream DC/DC converter input. Use Value: Limits transient excursions to ≤126 V, preventing damage to 100 V input-rated buck controllers and maintaining functional safety compliance. |
Use Scenario: Safeguarding analog outputs of pressure/temperature sensors in PLC modules exposed to relay switching noise. IC Role / Device Role / Timing Role: Low-capacitance shunt protector on 4–20 mA or 0–10 V output lines. Use Value: Sub-1 ns response and <1.0 µA leakage preserve signal accuracy while suppressing ±1 kV EFT bursts per IEC 61000-4-4. |
| MOSFET Gate Protection | Telecom DC Power Feeding |
|
Use Scenario: Preventing gate oxide rupture in high-side N-channel MOSFETs used in 48–80 V industrial motor drives. IC Role / Device Role / Timing Role: Cathode tied to gate, anode to source; clamps Miller-induced spikes during switching transitions. Use Value: 126 V clamping voltage ensures gate-source voltage stays within ±20 V absolute maximum rating of common 80 V MOSFETs. |
Use Scenario: Overvoltage protection on -48 V or -57 V DC feeding lines in telecom base station power distribution. IC Role / Device Role / Timing Role: Unidirectional clamp referenced to negative rail, absorbing positive-going surges from cable coupling. Use Value: 78 V VWM provides 20–30 V margin above nominal -48 V/-57 V rails while maintaining low standby leakage. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ78A-E3/57 | Same VWM (78 V), identical DO-214AC (SMA) package; slightly higher VC (127 V @ 4 A) and lower PPPM (400 W). | Surface-mount alternative for space-constrained designs; requires rework of footprint and thermal relief. | Select SMAJ78A-E3/57 when board real estate is limited and SMT assembly is preferred over through-hole. |
| 1.5KE78A | Higher PPPM (1500 W), larger DO-201AD package, same VWM/VBR range; 2× higher IFSM (200 A) but no AEC-Q101 qualification. | Used in non-automotive industrial power supplies where mechanical robustness and surge margin outweigh qualification needs. | Choose 1.5KE78A for high-energy surge environments (e.g., AC mains input stages) where qualification is secondary to energy handling. |
Compared with SMAJ78A-E3/57 and 1.5KE78A, SA78-E3/73 offers AEC-Q101 qualification and DO-15 through-hole compatibility in a cost-effective, proven automotive-grade form factor-ideal for legacy or service-sensitive designs requiring field-replaceable components and validated reliability.
Availability
SA78-E3/73 is available at Aetrix Electronics and suitable for automotive ECU power inputs, industrial sensor interface protection, and telecom DC feeding lines requiring stable component supply, long-lifecycle support, and RoHS-compliant sourcing.
Supply support for SA78-E3/73 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 qualification for harsh environments.
The SAxxA series is engineered for robust transient suppression in automotive, industrial, and telecom infrastructure-delivering consistent clamping performance and AEC-Q101 validation across the 5.0 V to 170 V VWM range.
FAQ
What is the maximum clamping voltage of SA78-E3/73 under rated surge conditions?
The SA78-E3/73 has a maximum clamping voltage (VC) of 126 V at 4 A peak pulse current (IPPM) using the standard 10/1000 µs waveform. This value is measured per Figure 7 in Vishay document 88378 and reflects the upper limit of voltage seen by downstream circuitry during a full-rated 500 W transient event. The SA78-E3/73 maintains this clamping performance across its specified operating temperature range.
Is SA78-E3/73 suitable for automotive applications requiring AEC-Q101 qualification?
Yes, SA78-E3/73 is explicitly AEC-Q101 qualified per Vishay documentation (note "(1) AEC-Q101 qualified" on page 3 of document 88378). It meets stress test requirements for temperature cycling, humidity bias, and high-temperature operating life-making it appropriate for engine control, body electronics, and ADAS modules. The SA78-E3/73 carries the "E3" suffix indicating RoHS-compliant commercial grade, and its qualification status is verified in the manufacturer's official qualification report.
What is the reverse leakage current of SA78-E3/73 at its rated stand-off voltage?
At VWM = 78 V and TA = 25 °C, the SA78-E3/73 exhibits a maximum reverse leakage current (ID) of 1.0 µA, as specified in the Electrical Characteristics table on page 2 of Vishay document 88378. This low leakage preserves signal integrity in high-impedance sensor interfaces and minimizes standby power loss in always-on automotive modules using the SA78-E3/73.
Does SA78-E3/73 have polarity marking, and how is it identified?
Yes, SA78-E3/73 is a unidirectional TVS diode with polarity clearly marked: a single color band on the body denotes the cathode terminal. The opposite end is the anode. This marking aligns with JEDEC DO-204AC mechanical drawings and is visible in Vishay's package outline diagram (page 5 of document 88378). Correct orientation is essential-reversal would disable transient protection on the intended line.
What is the steady-state power dissipation rating for SA78-E3/73, and under what conditions?
The SA78-E3/73 has a steady-state power dissipation (PD) rating of 3.0 W when mounted on an infinite heatsink at a lead temperature (TL) of 75 °C, as defined in the Maximum Ratings table (page 1 of document 88378). Derating is required above 75 °C per Figure 5; at TL = 100 °C, PD drops to ~2.0 W. This rating applies only to continuous DC or low-frequency conditions-not transient suppression duty cycles.
SA78-E3/73 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-204AC, DO-15, Axial
- Series:
- TransZorb®
- Packaging:
- Tape & Box (TB)
- 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-E3/73 FAQ
1.How can I place an order for SA78-E3/73 through Aetrix?
Please submit a Request for Quotation (RFQ) for SA78-E3/73 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-E3/73 reliable?
The price and inventory of SA78-E3/73 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SA78-E3/73 is usually 5 days.
3.What payment methods are accepted for SA78-E3/73?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SA78-E3/73 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SA78-E3/73?
SA78-E3/73 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SA78-E3/73 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-E3/73?
For technical support, including SA78-E3/73 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SA78-E3/73 requirements.
6.How does Aetrix verify that SA78-E3/73 is sourced from the original manufacturer or authorized distributors?
All SA78-E3/73 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-E3/73 meets industry standards.
7.What is the process for return or replacement of SA78-E3/73?
All SA78-E3/73 units undergo pre-shipment inspection (PSI). If there is an issue with SA78-E3/73, 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-E3/73 part is unused and in its original packaging.
Return procedure for SA78-E3/73:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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