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Vishay General Semiconductor - Diodes Division SA78HE3/73
- Part No.:
- SA78HE3/73
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-204AC, DO-15, Axial
- Datasheet:
-
SA78HE3/73.pdf
- Description:
- TVS DIODE 78VWM 139VC DO204AC
- Quantity:
- Payment:
- Shipping:
Inventory:4,023
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Product details
Overview
SA78HE3/73 from Vishay General Semiconductor is a bi-directional Transient Voltage Suppressor (TVS) diode in DO-204AC (DO-15) package, designed for clamping voltage transients on signal or power lines. It features a 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), 126 V maximum clamping voltage at 4 A, and AEC-Q101 qualification for automotive use.
For engineers reviewing the SA78HE3/73 datasheet, SA78HE3/73 pinout, SA78HE3/73 application, or SA78HE3/73 equivalent, this device is selected for robust overvoltage protection in automotive sensor interfaces, industrial I/O lines, and telecom line-card surge immunity where bi-directional clamping, low leakage (<1 µA at 78 V), and high surge current tolerance are required.
Technical Context
The SA78HE3/73 operates as a bi-directional avalanche diode, symmetrically clamping transient voltages above ±86.7 V in either polarity while maintaining <1 µA reverse leakage at its 78 V stand-off rating. Its glass-passivated junction ensures stable breakdown characteristics and long-term reliability under repetitive surge stress.
Designed for 10/1000 µs waveform compliance, it delivers 4 A peak pulse current (IPPM) with 126 V clamping, exhibits a +0.095 %/°C temperature coefficient of VBR, and supports operating junction temperatures from –55 °C to +175 °C - enabling deployment in under-hood automotive and industrial environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 78 V - Maximum continuous reverse working voltage before clamping initiates; defines safe operating margin for 72 V nominal systems. |
| VBR (min/max) | 86.7 V / 95.8 V at 1 mA - Confirmed avalanche threshold range; ensures predictable turn-on across production lot and temperature. |
| VC @ IPPM | 126 V at 4 A - Clamped voltage during 10/1000 µs surge; limits downstream IC stress to safe levels in 12 V/24 V automotive buses. |
| PPPM | 500 W - Peak pulse power handling per single transient; meets ISO 7637-2 Pulse 1/2/5a/b requirements for automotive electronics. |
| ID @ VWM | <1 µA - Ultra-low reverse leakage at rated stand-off; preserves signal integrity in high-impedance sensor or communication lines. |
| TJ max. | +175 °C - Maximum junction temperature; supports placement near heat sources in engine control units and power modules. |
| AEC-Q101 | Qualified - Validated for automotive-grade reliability including HTOL, TC, UHAST, and ESD testing per JESD47. |
Pinout & Package
Package: DO-204AC (DO-15), axial-leaded, molded epoxy case meeting UL 94 V-0; matte tin-plated leads solderable per J-STD-002; no polarity marking (bi-directional).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode/Cathode (symmetrical) | Bi-directional avalanche junction | No functional distinction between leads; interchangeable in PCB layout; enables simplified routing on differential or AC-coupled lines. |
| Lead 1 / Lead 2 | Current path terminals | Both leads conduct identically in forward or reverse bias beyond VBR; supports mounting without orientation check during automated assembly. |
Key Features
| Feature | Design Value |
|---|---|
| Bi-directional clamping | Enables single-device protection of AC signals, RS-485 buses, and ungrounded sensor outputs without polarity concerns. |
| Glass passivated junction | Ensures stable VBR and low leakage over 15+ years in humid or thermally cycled environments (e.g., automotive cabin modules). |
| 500 W peak pulse power (10/1000 µs) | Withstands multiple ISO 16750-2 load-dump surges up to 35 V × 100 ms without degradation when properly heatsinked. |
| AEC-Q101 qualification | Validated for automotive under-hood applications including engine control, transmission control, and ADAS sensor interfaces. |
| DO-204AC (DO-15) package | Industry-standard footprint compatible with legacy designs; supports wave and reflow soldering per JESD 22-B106 (275 °C, 10 s max). |
Applications
| Automotive Sensor Protection | Industrial I/O Line Protection |
|---|---|
Use Scenario: Protecting analog output lines of pressure, temperature, or position sensors in engine control units exposed to load dump and inductive switching noise. IC Role / Device Role / Timing Role: Bi-directional voltage clamp placed between sensor output and microcontroller ADC input to limit transients to ≤126 V. Use Value: Prevents ADC saturation and latch-up in 3.3 V/5 V MCUs while maintaining sub-1 µA leakage for accurate low-current sensing. | Use Scenario: Safeguarding 24 V DC digital input channels on PLC modules against field-wiring induced surges and ground bounce. IC Role / Device Role / Timing Role: Standoff protector mounted at connector entry point to shunt >1 kV transients before reaching optocoupler or Schmitt trigger input stage. Use Value: Eliminates need for external series impedance or RC filtering; maintains fast edge response (<1 ns turn-on) for 10 kHz digital signal integrity. |
| Telecom Line Card Surge Immunity | Consumer Power Adapter Input Protection |
Use Scenario: Front-end protection of POTS or xDSL line interface circuits subjected to lightning-induced surges per ITU-T K.20/K.44. IC Role / Device Role / Timing Role: Primary clamping device across tip/ring pair, coordinated with gas discharge tube (GDT) for staged protection. Use Value: Limits let-through voltage to <150 V during 10/700 µs surges, preserving SLIC and codec ICs rated for 160 V absolute maximum. | Use Scenario: Secondary-side transient suppression on 12 V DC output rails of wall adapters used in smart home hubs and set-top boxes. IC Role / Device Role / Timing Role: Fast-response clamp parallel to bulk capacitor to suppress ringing and ESD events from connected peripherals. Use Value: Reduces output voltage overshoot to <15 V during 8 kV contact ESD, preventing brownout resets in downstream SoCs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ78CA | Same VWM (78 V), higher PPPM (600 W), SMC (DO-214AB) package - 20 % larger footprint, lower thermal resistance. | Better suited for high-repetition surge environments (e.g., motor drive feedback lines) due to superior power dissipation. | Select SMBJ78CA when board space allows and thermal management requires >500 W pulse handling. |
| 1.5KE78CA | Same VWM (78 V), identical DO-204AC package, but 1.5 kW PPPM and higher IPPM (21.5 A); higher VC (129 V). | Targeted at high-energy lightning strike protection (IEC 61000-4-5 Level 4), not optimized for fast-edge ESD. | Choose 1.5KE78CA only when system-level testing confirms need for >1 kW surge capability and 129 V clamping is acceptable. |
Compared with SMBJ78CA and 1.5KE78CA, the SA78HE3/73 offers AEC-Q101 qualification and tighter VBR tolerance (±5 %) in the compact DO-15 form factor - making it optimal for space-constrained, automotive-grade designs where consistent clamping and qualification evidence are mandatory.
Availability
SA78HE3/73 is available at Aetrix Electronics and suitable for automotive sensor interfaces, industrial PLC I/O modules, and telecom line-card surge protection requiring stable component supply, RoHS-compliant sourcing, and AEC-Q101 traceability.
Supply support for SA78HE3/73 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, MOSFETs, and TVS devices with emphasis on reliability, power handling, and automotive qualification.
The SAxxHE3 series is part of Vishay's TRANSZORB® family, engineered specifically for AEC-Q101-compliant transient suppression in harsh automotive and industrial environments where bi-directional clamping, low leakage, and long-term stability are critical.
FAQ
What is the polarity configuration of the SA78HE3/73?
The SA78HE3/73 is a bi-directional TVS diode with symmetrical avalanche characteristics; neither lead is marked as anode or cathode, and both terminals function identically in either polarity. This eliminates orientation sensitivity during PCB assembly and supports AC-coupled or floating signal line protection without design constraints.
Does the SA78HE3/73 meet automotive reliability standards?
Yes, the SA78HE3/73 carries full AEC-Q101 qualification per the Vishay datasheet (Document Number: 88378, Revision: 18-Sep-12). It has passed stress tests including high-temperature operating life (HTOL), temperature cycling (TC), unbiased highly accelerated stress test (UHAST), and human-body-model ESD - confirming suitability for under-hood and chassis-mounted automotive ECUs.
What is the maximum clamping voltage of the SA78HE3/73 under standard surge conditions?
The SA78HE3/73 clamps to a maximum of 126 V when subjected to its rated 4 A peak pulse current (IPPM) using the industry-standard 10/1000 µs waveform. This value is guaranteed across temperature and production lot, ensuring predictable protection margins for 72 V nominal systems such as 24 V commercial vehicle electronics.
How does the SA78HE3/73 differ from the SA78A variant?
The SA78HE3/73 is the AEC-Q101-qualified, RoHS-compliant version with HE3 suffix (JESD 201 Class 2 whisker resistance), whereas SA78A is the commercial-grade, non-automotive variant. Both share identical electrical specs (VWM = 78 V, VBR = 86.7–95.8 V), but only SA78HE3/73 provides certified automotive reliability data and extended temperature validation.
Can the SA78HE3/73 be used in place of a unidirectional TVS like SA78A?
No - the SA78HE3/73 is strictly bi-directional and lacks polarity marking; substituting it for a unidirectional SA78A would compromise protection on DC-biased lines (e.g., 12 V power rails), where reverse conduction could cause short-circuit failure. Use only in AC, differential, or floating applications confirmed in the SA78HE3/73 datasheet.
SA78HE3/73 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:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 175°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-204AC (DO-15)
SA78HE3/73 FAQ
1.How can I place an order for SA78HE3/73 through Aetrix?
Please submit a Request for Quotation (RFQ) for SA78HE3/73 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 SA78HE3/73 reliable?
The price and inventory of SA78HE3/73 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SA78HE3/73 is usually 5 days.
3.What payment methods are accepted for SA78HE3/73?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SA78HE3/73 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SA78HE3/73?
SA78HE3/73 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SA78HE3/73 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 SA78HE3/73?
For technical support, including SA78HE3/73 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SA78HE3/73 requirements.
6.How does Aetrix verify that SA78HE3/73 is sourced from the original manufacturer or authorized distributors?
All SA78HE3/73 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 SA78HE3/73 meets industry standards.
7.What is the process for return or replacement of SA78HE3/73?
All SA78HE3/73 units undergo pre-shipment inspection (PSI). If there is an issue with SA78HE3/73, 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 SA78HE3/73 part is unused and in its original packaging.
Return procedure for SA78HE3/73:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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