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Vishay General Semiconductor - Diodes Division SA18HE3/73
- Part No.:
- SA18HE3/73
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-204AC, DO-15, Axial
- Datasheet:
-
SA18HE3/73.pdf
- Description:
- TVS DIODE 18VWM 32.2VC DO204AC
- Quantity:
- Payment:
- Shipping:
Inventory:6,669
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Product details
Overview
SA18HE3/73 from Vishay General Semiconductor is a uni-directional Transient Voltage Suppressor (TVS) diode in DO-204AC (DO-15) package, rated for 18 V stand-off voltage (VWM), 20.0–22.1 V breakdown voltage (VBR), 500 W peak pulse power (10/1000 µs), 17.1 A peak pulse current (IPPM), and clamping voltage of 29.2 V at IPPM. It protects MOSFETs and ICs against inductive switching transients in automotive power supplies.
For engineers reviewing the SA18HE3/73 datasheet, SA18HE3/73 pinout, SA18HE3/73 application, or SA18HE3/73 equivalent, key selection criteria include VWM/VBR tolerance, clamping ratio (VC/VBR ≈ 1.4), AEC-Q101 qualification, DO-15 thermal derating above 25 °C, and 70 A IFSM surge rating for load dump events.
Technical Context
This TVS operates as a voltage-clamped shunt protector: under normal bias it presents high impedance (<1 µA leakage at 18 V), but avalanches rapidly (<1 ps response) when reverse voltage exceeds VBR to divert transient energy away from downstream circuitry. Its glass-passivated junction ensures stable breakdown and low incremental surge resistance.
Designed for unidirectional DC line protection, SA18HE3/73 features a cathode band marking, supports 3.0 W steady-state dissipation on infinite heatsink at TL = 75 °C, and maintains operation across –55 °C to +175 °C junction temperature range with ±5 % VBR tolerance and +0.02 %/°C temperature coefficient.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - maximum continuous reverse operating voltage before clamping begins |
| VBR (min/max) | 20.0 V / 22.1 V - guaranteed avalanche onset range at 10 mA test current |
| VC @ IPPM | 29.2 V - clamped voltage during 17.1 A 10/1000 µs transient, limiting stress on protected IC |
| PPPM | 500 W - peak transient power handling per single 10/1000 µs pulse, 0.01 % duty cycle |
| IFSM | 70 A - non-repetitive forward surge current capability (10 ms half-sine), critical for load dump |
| TJ max | +175 °C - maximum junction temperature enabling under-hood automotive use |
| Polarity | Uni-directional - cathode-banded device; blocks forward current until VF ≈ 3.5 V at 100 A |
Pinout & Package
SA18HE3/73 uses the DO-204AC (DO-15) axial-leaded package: molded epoxy body (UL 94 V-0), matte tin-plated leads solderable per J-STD-002, 0.300" (7.6 mm) minimum lead length, and 0.140" (3.6 mm) maximum body diameter.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (banded end) | Cathode terminal | Marked end connects to system ground or low-side return; reverse-biased during clamping |
| Cathode (unmarked end) | Anode terminal | Connects to protected line (e.g., 12 V rail); conducts avalanche current to ground during overvoltage |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive applications including engine control units and body electronics |
| Glass passivated junction | Ensures stable VBR over lifetime and immunity to humidity-induced parameter shift |
| 500 W 10/1000 µs pulse rating | Handles ISO 7637-2 Pulse 1 (inductive switch-off) and Pulse 3a/b (line dump) waveforms |
| Low clamping ratio (VC/VBR ≈ 1.4) | Minimizes voltage overshoot during clamping, reducing risk of downstream IC latch-up |
| RoHS-compliant HE3 suffix | Meets JESD 201 Class 2 whisker resistance, suitable for high-reliability industrial assembly |
Applications
| Automotive Power Rail Protection | Industrial PLC Input Protection |
|---|---|
Use Scenario: 12 V battery-fed ECU power input subjected to load dump (ISO 7637-2 Pulse 5a) and alternator ripple. IC Role / Device Role / Timing Role: Shunt TVS placed between VBAT and chassis ground to clamp transients before they reach LDOs and microcontrollers. Use Value: With 29.2 V clamping at 17.1 A, SA18HE3/73 limits rail voltage to safe levels for 24 V-tolerant logic, preventing reset or damage during 120 V/100 ms surges. | Use Scenario: 24 V DC digital input module exposed to field-wiring inductive kickback from solenoid valves. IC Role / Device Role / Timing Role: Primary overvoltage clamp on each isolated input channel, upstream of optocoupler or Schmitt trigger. Use Value: 500 W pulse rating absorbs repetitive 100 V/100 µs transients without degradation, extending input stage MTBF in factory automation systems. |
| DC Motor Drive Gate Protection | Telecom Power Interface |
Use Scenario: High-side N-channel MOSFET gate driver supply (12 V) in H-bridge motor controller. IC Role / Device Role / Timing Role: Fast-acting clamp protecting gate oxide from Miller-induced voltage spikes during switching transitions. Use Value: Sub-nanosecond response and 29.2 V VC ensure gate-source voltage stays below 20 V absolute max, avoiding irreversible dielectric breakdown. | Use Scenario: -48 V telecom central office power feed interface subject to lightning-induced surges on tip/ring lines. IC Role / Device Role / Timing Role: Secondary-level TVS on DC-DC converter input stage, complementing primary gas discharge tube. Use Value: AEC-Q101 qualification and 175 °C TJ max support long-term reliability in sealed, convection-cooled enclosures with ambient up to 85 °C. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ18A-E3/5T | Same DO-214AC (SMA) package; 18 V VWM, 20–22.1 V VBR, but lower 400 W PPPM rating | Surface-mount footprint requires PCB redesign; lower thermal mass reduces IFSM margin | Select SMAJ18A-E3/5T only when space-constrained layouts preclude axial DO-15 placement |
| 1.5KE18A | Higher 1500 W PPPM, same DO-204AC package, but larger 1.5 kW case and 200 ns response vs. sub-ns | Overqualified for most 12 V systems; higher capacitance may affect high-speed signal integrity | Choose 1.5KE18A only for legacy designs requiring backward compatibility with existing 1.5 kW TVS footprints |
Compared with SMAJ18A-E3/5T and 1.5KE18A, SA18HE3/73 delivers optimal balance of AEC-Q101 compliance, 500 W pulse handling, and DO-15 manufacturability-making it preferred for new automotive and industrial designs where reliability and through-hole assembly are prioritized.
Availability
SA18HE3/73 is available at Aetrix Electronics and suitable for automotive ECUs, industrial PLCs, and DC motor drives requiring stable component supply with full traceability and long-lifecycle support.
Supply support for SA18HE3/73 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 protection devices with emphasis on automotive-grade reliability and AEC-Q101 validation.
The SAxxA series-including SA18HE3/73-is engineered specifically for robust transient suppression in 12 V/24 V automotive and industrial power systems, targeting high-temperature, high-surge environments where failure is not an option.
FAQ
What is the clamping voltage of SA18HE3/73 at its rated peak pulse current?
The SA18HE3/73 has a maximum clamping voltage (VC) of 29.2 V when subjected to its rated peak pulse current (IPPM) of 17.1 A under the standard 10/1000 µs waveform. This value is measured per Figure 7 in the Vishay datasheet 88378 and defines the upper voltage limit imposed on protected circuitry during transient events. Maintaining VC below 30 V ensures compatibility with 3.3 V and 5 V logic interfaces downstream of the SA18HE3/73.
Is SA18HE3/73 suitable for automotive applications?
Yes, SA18HE3/73 is AEC-Q101 qualified and explicitly designed for automotive use, including engine control units, body control modules, and infotainment power supplies. Its DO-204AC package meets JESD 201 Class 2 whisker resistance, and its –55 °C to +175 °C operating range supports under-hood deployment. The SA18HE3/73 datasheet confirms qualification per AEC-Q101 Rev G, making it appropriate for production vehicles where reliability is mandated.
What does the "HE3" suffix indicate in SA18HE3/73?
The "HE3" suffix in SA18HE3/73 denotes RoHS-compliant construction with AEC-Q101 qualification and JESD 201 Class 2 whisker resistance. Unlike the base "E3" variant (commercial grade), HE3 guarantees automotive-grade process controls, extended temperature validation, and enhanced plating durability for reflow and wave soldering. This distinction is documented in the Mechanical Data section of Vishay document 88378.
How does SA18HE3/73 differ from bi-directional TVS diodes like SA18CA?
SA18HE3/73 is uni-directional and features a cathode band for polarity-sensitive placement, while SA18CA is bi-directional with no polarity marking and symmetric clamping in both directions. SA18HE3/73 offers lower forward voltage drop (VF = 3.5 V at 100 A) and higher IFSM (70 A), making it better suited for DC power rail protection. In contrast, SA18CA is intended for AC signal lines or differential buses where bidirectional clamping is required.
Can SA18HE3/73 be used in parallel for higher power handling?
No, SA18HE3/73 should not be paralleled without external balancing components. Due to manufacturing tolerances in VBR (20.0–22.1 V), mismatched avalanche onset causes current hogging-where one device conducts most of the transient energy and fails prematurely. Vishay does not recommend paralleling SA18HE3/73 devices. For higher power needs, select a single higher-rated part such as SA22HE3/73 or consult Vishay's application note AN8002 for derated multi-device configurations.
SA18HE3/73 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):
- 18V
- Voltage - Breakdown (Min):
- 20V
- Voltage - Clamping (Max) @ Ipp:
- 32.2V
- Current - Peak Pulse (10/1000µs):
- 15.5A
- 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)
SA18HE3/73 FAQ
1.How can I place an order for SA18HE3/73 through Aetrix?
Please submit a Request for Quotation (RFQ) for SA18HE3/73 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 SA18HE3/73 reliable?
The price and inventory of SA18HE3/73 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SA18HE3/73 is usually 5 days.
3.What payment methods are accepted for SA18HE3/73?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SA18HE3/73 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SA18HE3/73?
SA18HE3/73 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SA18HE3/73 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 SA18HE3/73?
For technical support, including SA18HE3/73 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SA18HE3/73 requirements.
6.How does Aetrix verify that SA18HE3/73 is sourced from the original manufacturer or authorized distributors?
All SA18HE3/73 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 SA18HE3/73 meets industry standards.
7.What is the process for return or replacement of SA18HE3/73?
All SA18HE3/73 units undergo pre-shipment inspection (PSI). If there is an issue with SA18HE3/73, 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 SA18HE3/73 part is unused and in its original packaging.
Return procedure for SA18HE3/73:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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