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Vishay General Semiconductor - Diodes Division SMAJ20HE3/5A
- Part No.:
- SMAJ20HE3/5A
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ20HE3/5A.pdf
- Description:
- TVS DIODE 20VWM 35.8VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:5,761
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Product details
Overview
SMAJ20HE3/5A from Vishay General Semiconductor is a high-reliability, AEC-Q101-qualified unidirectional Transient Voltage Suppressor (TVS) diode in DO-214AC (SMA) package, designed for automotive and industrial overvoltage protection. It features a 20 V stand-off voltage (VWM), 22.2–27.1 V breakdown voltage (VBR at 1 mA), 35.8 V maximum clamping voltage (VC) at 11.2 A peak pulse current, and 400 W peak pulse power rating with 10/1000 µs waveform.
For engineers reviewing the SMAJ20HE3/5A datasheet, SMAJ20HE3/5A pinout, SMAJ20HE3/5A application, or SMAJ20HE3/5A equivalent, this device serves as a robust, RoHS-compliant surge protector for 12 V automotive power rails, sensor signal lines, and MOSFET gate drivers requiring high surge immunity and MSL Level 1 reflow compatibility.
Technical Context
This unidirectional TVS diode operates as a voltage-clamped shunt protector: under normal conditions it presents high impedance (<1 µA leakage at 20 V), then rapidly avalanches to clamp transients within nanoseconds. Its glass-passivated junction ensures stable VBR tolerance and low dynamic impedance, critical for consistent clamping performance across temperature.
The device is rated for 40 A non-repetitive forward surge current (8.3 ms half-sine), supports 150 °C maximum junction temperature, and exhibits 30 °C/W typical junction-to-lead thermal resistance - enabling reliable operation on standard 5.0 × 5.0 mm copper pads without heatsinking in most automotive PCB layouts.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 20 V - Maximum continuous reverse operating voltage before conduction begins; defines safe working range for 12 V nominal systems. |
| VBR (min/max) | 22.2 V / 27.1 V at 1 mA - Tight breakdown window ensures predictable turn-on and avoids false triggering during load dump spikes. |
| VC @ IPPM | 35.8 V at 11.2 A - Clamping voltage limits downstream IC stress during ISO 7637-2 Pulse 1/2a/5a events. |
| PPPM | 400 W (10/1000 µs) - Sustains automotive-grade surge energy without degradation; derated to 300 W above 78 V. |
| IFSM | 40 A (8.3 ms half-sine) - Withstands repetitive load dump surges common in alternator-regulated vehicle electrical systems. |
| TJ Range | −55 °C to +150 °C - Fully qualified for under-hood automotive environments per AEC-Q101. |
| Package | DO-214AC (SMA) - Surface-mount, low-profile package compatible with automated placement and IR reflow (260 °C peak). |
Pinout & Package
DO-214AC (SMA) package: molded plastic case with matte tin-plated leads; cathode indicated by band on one end; terminals are anode and cathode - no internal circuitry or active pins beyond the two-terminal diode structure.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry terminal in forward bias | Connected to protected line (e.g., 12 V rail or signal trace); must be routed with low-inductance path to ground reference. |
| Cathode (banded end) | Current exit terminal in forward bias; clamping node | Connected to system ground; determines clamping reference level; layout must minimize inductance to preserve nanosecond response. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive use including temperature cycling, humidity, and mechanical shock - eliminates need for additional qualification testing. |
| Glass-passivated junction | Ensures stable VBR over time and temperature; prevents parameter drift in harsh under-hood environments. |
| MSL Level 1 rating | Compatible with standard SMT reflow profiles up to 260 °C peak; no baking required prior to assembly. |
| Low incremental surge resistance | Minimizes VC overshoot during fast transients (e.g., ESD or inductive switching), improving protection margin for sensitive ICs. |
| RoHS-compliant, high-reliability HE3 suffix | Dual compliance with EU RoHS 2002/95/EC and JESD201 Class 2 whisker resistance - suitable for long-life automotive modules. |
Applications
| Automotive Power Rail Protection | Industrial Sensor Interface Protection |
|---|---|
Use Scenario: Protecting 12 V battery-fed ECUs against load dump (ISO 7637-2 Pulse 5a) and jump-start surges. IC Role / Device Role / Timing Role: Shunt clamping device placed between power rail and chassis ground; responds in <1 ns to limit voltage excursion. Use Value: Clamps peak voltage to ≤35.8 V, preventing damage to 36 V-rated DC-DC converters and microcontrollers. |
Use Scenario: Safeguarding analog outputs of pressure/temperature sensors exposed to cable discharge or ESD events. IC Role / Device Role / Timing Role: Bidirectional transient suppressor (used unidirectionally here) across sensor supply and output lines. Use Value: Limits induced transients to <36 V while maintaining <1 µA leakage at 20 V, preserving sensor accuracy and offset stability. |
| MOSFET Gate Driver Protection | Telecom Line Interface Protection |
Use Scenario: Shielding high-side N-channel MOSFET gates from inductive kickback during motor or solenoid switching. IC Role / Device Role / Timing Role: Fast-acting voltage clamp referenced to driver IC ground; placed directly at gate-source terminals. Use Value: Prevents gate oxide rupture by limiting VGS to ≤35.8 V during 100 ns–1 µs transients, supporting 20 V-rated MOSFETs. |
Use Scenario: Protecting RS-485 transceivers connected to outdoor wiring subject to lightning-induced surges. IC Role / Device Role / Timing Role: Primary-level TVS on bus lines (A/B) and power input; coordinated with secondary GDT or MOV stages. Use Value: Absorbs 400 W surge energy per line while holding clamping voltage below transceiver absolute maximum ratings (e.g., ±15 V). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ20AHE3/5A | Bidirectional variant (CA suffix implied); symmetrical VBR = 22.2–24.5 V; same VC = 32.4 V at 12.3 A. | Required where AC-coupled or polarity-agnostic protection is needed (e.g., differential data lines). | Select SMAJ20AHE3/5A only if bidirectional clamping is mandatory; SMAJ20HE3/5A offers lower leakage and tighter VBR tolerance for DC rails. |
| SMCJ20HE3/5A | Same VWM/VBR but higher PPPM = 1500 W (10/1000 µs); DO-214AB (SMC) package - 2.5× larger footprint. | Suitable for higher-energy threats (e.g., ISO 16750-2 long-duration surges) where board space permits. | Choose SMAJ20HE3/5A when footprint and cost are constrained and 400 W rating suffices; upgrade to SMCJ20HE3/5A only for >1 kV/m surge immunity requirements. |
Compared with SMAJ20AHE3/5A, the SMAJ20HE3/5A provides superior unidirectional leakage control and tighter VBR consistency, while SMCJ20HE3/5A delivers 3.75× higher surge energy handling at the expense of PCB area and thermal mass - making SMAJ20HE3/5A optimal for space-constrained automotive body electronics.
Availability
SMAJ20HE3/5A is available at Aetrix Electronics and suitable for automotive control units, industrial sensor nodes, and telecom interface modules requiring stable component supply, AEC-Q101 compliance, and long-term lifecycle support.
Supply support for SMAJ20HE3/5A 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 high-reliability diodes, MOSFETs, and passive components for automotive, industrial, and computing markets.
The SMAJ series is engineered specifically for automotive-grade transient suppression - delivering AEC-Q101 qualification, extended temperature operation, and robust surge handling in compact surface-mount packages.
FAQ
What is the clamping voltage of SMAJ20HE3/5A at its rated peak pulse current?
The SMAJ20HE3/5A has a maximum clamping voltage (VC) of 35.8 V at 11.2 A peak pulse current (IPPM) with a 10/1000 µs waveform. This value is guaranteed per Vishay Document 88390 and defines the upper voltage limit imposed on protected circuits during standardized surge events - critical for ensuring downstream ICs remain within their absolute maximum ratings.
Is SMAJ20HE3/5A suitable for automotive applications?
Yes, SMAJ20HE3/5A is explicitly qualified to AEC-Q101 standards and carries the HE3 suffix denoting high-reliability, automotive-grade construction. It operates from −55 °C to +150 °C, meets MSL Level 1, and is validated for load dump, ESD, and inductive switching transients per ISO 7637-2 and ISO 10605 - making it fully suitable for engine control, body electronics, and ADAS modules.
What does the "HE3" suffix mean in SMAJ20HE3/5A?
The "HE3" suffix in SMAJ20HE3/5A indicates RoHS-compliant, high-reliability construction meeting JESD201 Class 2 whisker resistance and AEC-Q101 qualification. It distinguishes this part from commercial-grade "E3" variants and confirms suitability for automotive and industrial applications demanding extended lifetime and environmental robustness.
How does SMAJ20HE3/5A differ from SMAJ20AHE3/5A?
SMAJ20HE3/5A is unidirectional with cathode band marking and 1 µA max leakage at 20 V, while SMAJ20AHE3/5A is bidirectional (no polarity marking) with doubled leakage (2 µA) at VWM ≤10 V - though both share identical VWM = 20 V and similar clamping performance. The unidirectional version is preferred for DC power rail protection due to lower leakage and tighter VBR tolerance.
What PCB pad layout is recommended for optimal thermal and surge performance of SMAJ20HE3/5A?
Vishay specifies mounting SMAJ20HE3/5A on 0.2 × 0.2 inch (5.0 × 5.0 mm) copper pads per terminal to achieve rated 400 W peak pulse power. Smaller pads reduce thermal dissipation and surge current capability; thermal vias under pads improve heat transfer. Layout must minimize trace inductance between cathode and ground plane to preserve sub-nanosecond response.
SMAJ20HE3/5A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AC, SMA
- Series:
- TransZorb®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 20V
- Voltage - Breakdown (Min):
- 22.2V
- Voltage - Clamping (Max) @ Ipp:
- 35.8V
- Current - Peak Pulse (10/1000µs):
- 11.2A
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ20HE3/5A FAQ
1.How can I place an order for SMAJ20HE3/5A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ20HE3/5A 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 SMAJ20HE3/5A reliable?
The price and inventory of SMAJ20HE3/5A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ20HE3/5A is usually 5 days.
3.What payment methods are accepted for SMAJ20HE3/5A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ20HE3/5A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ20HE3/5A?
SMAJ20HE3/5A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ20HE3/5A 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 SMAJ20HE3/5A?
For technical support, including SMAJ20HE3/5A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ20HE3/5A requirements.
6.How does Aetrix verify that SMAJ20HE3/5A is sourced from the original manufacturer or authorized distributors?
All SMAJ20HE3/5A 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 SMAJ20HE3/5A meets industry standards.
7.What is the process for return or replacement of SMAJ20HE3/5A?
All SMAJ20HE3/5A units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ20HE3/5A, 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 SMAJ20HE3/5A part is unused and in its original packaging.
Return procedure for SMAJ20HE3/5A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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