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Vishay General Semiconductor - Diodes Division SMAJ28HE3/5A
- Part No.:
- SMAJ28HE3/5A
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ28HE3/5A.pdf
- Description:
- TVS DIODE 28VWM 50VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:6,699
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Product details
Overview
SMAJ28HE3/5A from Vishay General Semiconductor is a high-reliability, AEC-Q101-qualified unidirectional transient voltage suppressor (TVS) in DO-214AC (SMA) package, designed for automotive and industrial overvoltage protection. It features 28 V stand-off voltage (VWM), 50.0 V maximum clamping voltage (VC) at 8.0 A peak pulse current (IPPM), 400 W peak pulse power (10/1000 µs), and operates from −55 °C to +150 °C junction temperature.
For engineers reviewing the SMAJ28HE3/5A datasheet, SMAJ28HE3/5A pinout, SMAJ28HE3/5A application, or SMAJ28HE3/5A equivalent, this device is selected for robust ESD and surge protection on power rails and signal lines where automotive-grade reliability, low clamping ratio, and high surge current handling are required.
Technical Context
The SMAJ28HE3/5A uses a glass-passivated silicon avalanche junction optimized for fast response (<1 ps) and low incremental surge resistance. Its unidirectional configuration provides forward conduction capability with 3.5 V forward voltage (VF) at 25 A, enabling use in DC power line protection with polarity-aware clamping.
Thermal performance is defined by RθJA = 120 °C/W (typ.) and RθJL = 30 °C/W (typ.), supporting reliable operation under repetitive surge conditions when mounted on 0.2 × 0.2" copper pads. The device meets MSL Level 1 per J-STD-020 and is qualified to AEC-Q101 for automotive underhood and chassis applications.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Stand-off Voltage (VWM) | 28 V - Maximum continuous reverse operating voltage before clamping begins |
| Clamping Voltage (VC) | 50.0 V at 8.0 A - Limits transient voltage seen by protected circuit during 10/1000 µs surge |
| Peak Pulse Power (PPPM) | 400 W - Sustains single 10/1000 µs transients without failure; derated above 78 V |
| Breakdown Voltage (VBR) | 31.1–38.0 V at 1.0 mA - Confirms avalanche onset within specified tolerance band |
| Reverse Leakage (ID) | ≤1.0 µA at 28 V - Ensures minimal standby power loss in always-on systems |
| Junction Temperature Range | −55 °C to +150 °C - Supports operation in automotive engine compartments and industrial enclosures |
| Surge Current (IPPM) | 8.0 A - Peak current handled at VC; defines minimum PCB trace sizing and layout margin |
Pinout & Package
Package: DO-214AC (SMA), surface-mount, matte tin-plated leads, RoHS-compliant, AEC-Q101 qualified. Cathode indicated by band marking on body.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward current entry / Reverse surge return path | Connected to protected circuit ground or lower-potential rail; must handle full IPPM surge current |
| Cathode | Clamping node / Surge sink | Connected to line being protected; clamps voltage to ≤50.0 V when transient exceeds 28 V |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive underhood use with extended temperature cycling, humidity, and mechanical shock compliance |
| 400 W peak pulse power | Withstands ISO 7637-2 Pulse 1, 2a, 3a/b, and IEC 61000-4-5 Level 3 surges without degradation |
| Glass-passivated junction | Ensures stable VBR and low leakage over lifetime, even under thermal stress and humidity exposure |
| MSL Level 1 rating | Allows unlimited floor life and reflow up to 260 °C peak, compatible with standard SMT assembly processes |
| Low clamping ratio (VC/VWM = 1.79) | Minimizes overvoltage stress on downstream ICs compared to higher-ratio TVS devices |
Applications
| Automotive Power Rail Protection | Industrial Sensor Signal Line Protection |
|---|---|
Use Scenario: Protecting 24 V battery-fed ECUs against load dump and alternator transients. IC Role / Device Role / Timing Role: Unidirectional TVS placed between power input and ground to clamp positive-going surges above 28 V. Use Value: Limits voltage to ≤50.0 V during 400 W transients, preventing damage to 36 V-rated regulators and microcontrollers. |
Use Scenario: Shielding analog outputs of pressure/temperature sensors in factory automation PLC modules. IC Role / Device Role / Timing Role: TVS connected across sensor output and ground to absorb ESD and inductive switching noise. Use Value: Sub-1 µA leakage preserves µA-level sensor bias accuracy; 50.0 V clamping protects 24 V-tolerant ADC inputs. |
| Telecom DC Power Input Protection | Motor Drive Control Signal Isolation |
Use Scenario: Safeguarding PoE-powered network switches against lightning-induced surges on 48 V DC input. IC Role / Device Role / Timing Role: Primary clamping device on main DC bus, upstream of DC/DC converters. Use Value: 400 W rating handles multi-kV induced transients; DO-214AC footprint enables compact, high-density layout. |
Use Scenario: Protecting isolated gate driver enable signals in BLDC motor inverters exposed to commutation noise. IC Role / Device Role / Timing Role: Bidirectional-capable unidirectional TVS (cathode grounded) shunts fast dv/dt spikes on logic-level control lines. Use Value: 8.0 A IPPM withstands repetitive 50 ns–100 ns edge transients; 120 °C/W RθJA supports thermal design in sealed enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ28AHE3/5A | Lower breakdown range (31.1–34.4 V vs. 31.1–38.0 V); tighter VBR tolerance | Better suited for precision 28 V rail clamping where upper VBR margin must be minimized | Select SMAJ28AHE3/5A when system VBR margin is constrained and tighter distribution is required |
| SMCJ28HE3/5A | DO-214AB (SMC) package; 1500 W PPPM; same VWM/VC but higher IPPM (33.3 A) | Used where higher surge energy (e.g., ISO 16750-2 long-duration pulses) demands larger package thermal mass | Choose SMCJ28HE3/5A only if layout allows larger footprint and surge requirement exceeds 400 W |
Compared with SMAJ28HE3/5A, SMAJ28AHE3/5A offers tighter VBR control for critical 28 V systems, while SMCJ28HE3/5A trades DO-214AC compactness for 3.75× higher surge capacity-neither is pin-compatible, and both require PCB redesign.
Availability
SMAJ28HE3/5A is available at Aetrix Electronics and suitable for automotive electronics, industrial sensor interfaces, and telecom power input protection requiring stable component supply, AEC-Q101 compliance, and consistent surge performance across production lots.
Supply support for SMAJ28HE3/5A 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 diodes, rectifiers, TVS, MOSFETs, and optoelectronics with emphasis on reliability, efficiency, and automotive-grade qualification.
The SMAJ series is engineered specifically for high-reliability transient suppression in harsh environments, targeting automotive power distribution, industrial control, and infrastructure equipment where failure modes must be rigorously controlled.
FAQ
What is the clamping voltage of SMAJ28HE3/5A at its rated peak pulse current?
The SMAJ28HE3/5A has a maximum clamping voltage (VC) of 50.0 V at 8.0 A peak pulse current (IPPM) under the standard 10/1000 µs waveform. This value is guaranteed per Vishay Document Number 88390, ensuring predictable overvoltage limiting for downstream components in the protected circuit. The SMAJ28HE3/5A maintains this clamping performance across its full operating temperature range.
Is SMAJ28HE3/5A qualified for automotive applications?
Yes, SMAJ28HE3/5A is explicitly AEC-Q101 qualified and designated as high-reliability/automotive grade (HE3 suffix). It undergoes stress testing including temperature cycling, humidity bias, mechanical shock, and solder heat resistance per AEC standards. The SMAJ28HE3/5A is approved for underhood and chassis-mounted systems where ambient temperatures reach +125 °C and beyond.
What does the "HE3" suffix indicate in SMAJ28HE3/5A?
The "HE3" suffix in SMAJ28HE3/5A denotes RoHS-compliant, high-reliability/automotive-grade construction meeting AEC-Q101 requirements. It distinguishes the part from commercial-grade "E3" variants and confirms enhanced whisker resistance (JESD 201 Class 2), extended temperature capability, and process controls validated for automotive production. The SMAJ28HE3/5A is not interchangeable with non-HE3 versions in safety-critical designs.
Can SMAJ28HE3/5A be used in bidirectional protection circuits?
No, SMAJ28HE3/5A is a unidirectional TVS diode and is not rated for bidirectional operation. Its electrical characteristics apply only in reverse-biased (clamping) and forward-biased (conduction) modes-not symmetrically. For bidirectional protection, Vishay specifies CA-suffix parts like SMAJ28CA; using SMAJ28HE3/5A in such configurations risks asymmetric clamping and potential failure. Always verify polarity alignment in the SMAJ28HE3/5A layout.
What is the thermal resistance of SMAJ28HE3/5A, and how does it affect layout?
The SMAJ28HE3/5A has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W when mounted on 0.2 × 0.2" copper pads per Vishay's recommended layout. This value directly impacts sustained surge handling: higher ambient temperatures or undersized pads increase junction temperature, potentially derating IPPM. To maintain reliability, the SMAJ28HE3/5A must be placed on thermally adequate copper areas and avoid proximity to other heat sources.
SMAJ28HE3/5A 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):
- 28V
- Voltage - Breakdown (Min):
- 31.1V
- Voltage - Clamping (Max) @ Ipp:
- 50V
- Current - Peak Pulse (10/1000µs):
- 8A
- 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)
SMAJ28HE3/5A FAQ
1.How can I place an order for SMAJ28HE3/5A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ28HE3/5A 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 SMAJ28HE3/5A reliable?
The price and inventory of SMAJ28HE3/5A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ28HE3/5A is usually 5 days.
3.What payment methods are accepted for SMAJ28HE3/5A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ28HE3/5A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ28HE3/5A?
SMAJ28HE3/5A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ28HE3/5A 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 SMAJ28HE3/5A?
For technical support, including SMAJ28HE3/5A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ28HE3/5A requirements.
6.How does Aetrix verify that SMAJ28HE3/5A is sourced from the original manufacturer or authorized distributors?
All SMAJ28HE3/5A 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 SMAJ28HE3/5A meets industry standards.
7.What is the process for return or replacement of SMAJ28HE3/5A?
All SMAJ28HE3/5A units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ28HE3/5A, 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 SMAJ28HE3/5A part is unused and in its original packaging.
Return procedure for SMAJ28HE3/5A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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