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Vishay General Semiconductor - Diodes Division SMAJ28-E3/5A
- Part No.:
- SMAJ28-E3/5A
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ28-E3/5A.pdf
- Description:
- TVS DIODE 28VWM 50VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:2,050
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Product details
Overview
SMAJ28-E3/5A from Vishay General Semiconductor is a unidirectional surface-mount Transient Voltage Suppressor (TVS) diode in DO-214AC (SMA) package, designed for clamping voltage transients on power and signal lines. It features a 28 V stand-off voltage (VWM), 31.1–38.0 V breakdown voltage (VBR at 1 mA), 50.0 V maximum clamping voltage (VC) at 8.0 A peak pulse current, and 400 W peak pulse power rating with 10/1000 µs waveform - used to protect MOSFETs, ICs, and sensor interfaces in industrial and automotive electronics.
For engineers reviewing the SMAJ28-E3/5A datasheet, SMAJ28-E3/5A pinout, SMAJ28-E3/5A application, or SMAJ28-E3/5A equivalent, key selection criteria include its unidirectional polarity, 1.0 µA max reverse leakage at VWM, 150 °C max junction temperature, RoHS-compliant matte tin terminals, and suitability for automated SMT placement on PCBs with 5.0 × 5.0 mm copper pads per terminal.
Technical Context
This TVS diode operates as a clamping device that remains high-impedance below 28 V and rapidly transitions to low-impedance conduction above its breakdown threshold. Its glass-passivated junction ensures stable VBR tolerance (±10 %) and low incremental surge resistance, enabling consistent clamping performance under repetitive 10/1000 µs surges at 0.01 % duty cycle.
The SMAJ28-E3/5A is rated for 40 A non-repetitive forward surge current (8.3 ms half-sine), supports MSL Level 1 moisture sensitivity, and meets JESD201 Class 1A whisker resistance. Thermal resistance is 120 °C/W (junction-to-ambient) and 30 °C/W (junction-to-lead), requiring appropriate pad layout for thermal management during transient events.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 28 V - Maximum continuous reverse operating voltage before clamping begins; defines safe DC/AC working range. |
| VBR (min/max) | 31.1 V / 38.0 V at 1 mA - Confirmed breakdown range ensuring reliable turn-on margin above VWM. |
| VC @ IPPM | 50.0 V at 8.0 A - Clamped voltage during 10/1000 µs surge; determines protected circuit's maximum stress level. |
| PPPM | 400 W - Peak pulse power handling capability with standard 10/1000 µs waveform; derates above 78 V. |
| IFSM | 40 A - Single 8.3 ms half-sine surge current rating; validates robustness against inductive switch-off events. |
| TJ Range | −55 °C to +150 °C - Operating and storage junction temperature range; supports under-hood automotive use. |
| Leakage @ VWM | ≤1.0 µA - Low reverse leakage preserves signal integrity and minimizes standby power loss. |
Pinout & Package
Package: DO-214AC (SMA), surface-mount, low-profile case with matte tin-plated leads solderable per J-STD-002 and JESD22-B102. Cathode indicated by band marking on body.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward current entry (uni-directional) | Connected to lower-potential side of protected line; conducts during reverse transient when cathode is positive. |
| Cathode | Reverse-biased reference terminal | Marked end; connects to higher-potential rail (e.g., VCC or signal line); defines clamping polarity and directionality. |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Ensures stable VBR over temperature and lifetime; eliminates parameter drift from environmental exposure. |
| 400 W peak pulse power (10/1000 µs) | Provides robust protection against IEC 61000-4-5 Level 4 surges without degradation across 1000+ events. |
| MSL Level 1, 260 °C reflow compatible | Enables single-pass lead-free reflow assembly without preconditioning or special handling. |
| RoHS-compliant, JESD201 Class 1A whisker resistant | Validates long-term reliability in high-vibration environments including automotive ECUs and industrial controls. |
| Low incremental surge resistance | Minimizes VC overshoot during fast-rising transients (<1 ns response), improving protection margin for sensitive ICs. |
Applications
| Automotive Power Line Protection | Industrial Sensor Interface Protection |
|---|---|
|
Use Scenario: Protecting 12 V battery-fed control modules from load dump and alternator ripple transients. IC Role / Device Role: Unidirectional TVS placed between VBAT and GND to clamp spikes up to ±100 V. Use Value: Limits voltage seen by downstream LDOs and microcontrollers to ≤50.0 V, preventing latch-up or gate oxide damage. |
Use Scenario: Safeguarding analog output lines (e.g., 4–20 mA current loops) from ESD and field wiring faults. IC Role / Device Role: TVS mounted across signal and return path to absorb ±8 kV contact ESD per IEC 61000-4-2. Use Value: Maintains signal fidelity with <1.0 µA leakage at 28 V, avoiding offset errors in precision current sensing. |
| DC-DC Converter Input Stage | MOSFET Gate Driver Protection |
|
Use Scenario: Shielding buck converter input from inductive kickback during hot-plug or relay switching. IC Role / Device Role: Primary clamping device on VIN rail upstream of input capacitor and controller. Use Value: Absorbs 400 W surges without thermal runaway, preserving converter uptime in factory automation systems. |
Use Scenario: Preventing gate oxide rupture in high-side N-channel MOSFET drivers exposed to Miller-induced spikes. IC Role / Device Role: TVS connected between gate and source to clamp dv/dt-induced transients. Use Value: Responds in <1 ns to limit gate-source voltage to ≤50.0 V, eliminating false turn-on and shoot-through risk. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ28A-E3/5A | Lower VBR range (31.1–34.4 V); tighter 5 % tolerance vs. 10 % for SMAJ28-E3/5A. | Better suited for designs requiring tighter clamping threshold control near 28 V nominal rails. | Select SMAJ28A-E3/5A when VBR consistency is critical; SMAJ28-E3/5A offers wider margin for variable supply conditions. |
| SMBJ28A-E3/52 | Same VWM/VC specs but in larger DO-214AA (SMB) package; 600 W PPPM rating. | Higher power handling supports longer surge durations or higher repetition rates in harsh environments. | Choose SMBJ28A-E3/52 only if board space allows and 600 W capability is required; SMAJ28-E3/5A optimizes footprint-constrained layouts. |
Compared with SMAJ28A-E3/5A, the SMAJ28-E3/5A provides broader VBR tolerance for relaxed design margins, while SMBJ28A-E3/52 trades smaller size for higher surge capacity - making SMAJ28-E3/5A optimal for cost- and space-sensitive 400 W protection where 10 % VBR variation is acceptable.
Availability
SMAJ28-E3/5A is available at Aetrix Electronics and suitable for automotive power distribution, industrial sensor interface, and DC-DC converter input protection requiring stable component supply, full traceability, and long-term lifecycle support.
Supply support for SMAJ28-E3/5A 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 demanding industrial and automotive applications.
The SMAJ series was engineered specifically for surface-mount transient suppression in space-constrained, high-surge environments - emphasizing low-profile packaging, repeatable clamping, and AEC-Q101 readiness for under-hood electronics.
FAQ
What is the polarity configuration of the SMAJ28-E3/5A?
The SMAJ28-E3/5A is a unidirectional TVS diode, with the banded end denoting the cathode terminal. It conducts only when the cathode is at a higher potential than the anode, making it suitable for DC rail protection where polarity is fixed. This differs from bi-directional variants (e.g., SMAJ28CA) which suppress surges regardless of polarity.
Does the SMAJ28-E3/5A meet automotive qualification standards?
The SMAJ28-E3/5A is RoHS-compliant and rated for MSL Level 1, but it is not AEC-Q101 qualified. For automotive-grade applications, Vishay offers the HE3-suffix variant (e.g., SMAJ28HE3/5A), which undergoes extended reliability testing per AEC-Q101. The SMAJ28-E3/5A is intended for commercial and industrial use where full automotive qualification is not required.
What is the recommended PCB pad layout for optimal thermal performance of the SMAJ28-E3/5A?
Vishay specifies a minimum 0.2 × 0.2 inch (5.0 × 5.0 mm) copper pad area for each terminal of the SMAJ28-E3/5A to achieve its rated 400 W peak pulse power. Smaller pads reduce thermal dissipation, causing premature failure under repeated surges. Use solid internal ground/power planes connected via multiple vias to enhance heat spreading and maintain junction temperature within −55 °C to +150 °C limits.
How does the clamping voltage VC = 50.0 V at 8.0 A translate to real-world protection capability?
The SMAJ28-E3/5A clamps to ≤50.0 V when subjected to an 8.0 A, 10/1000 µs surge - meaning any downstream component rated for >50 V absolute maximum will remain undamaged. For example, a 3.3 V MCU with 6 V absolute max I/O pins would require additional series impedance to limit current into the TVS; the SMAJ28-E3/5A alone protects devices with ≥50 V withstand ratings.
Can the SMAJ28-E3/5A be used in bi-directional signal line protection?
No - the SMAJ28-E3/5A is unidirectional and unsuitable for AC or bidirectional signal paths without external biasing. For such applications, use the bi-directional SMAJ28CA variant, which exhibits symmetric clamping in both directions and carries no polarity marking. Substituting SMAJ28-E3/5A in bi-directional roles risks forward conduction and permanent damage during negative transients.
SMAJ28-E3/5A 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:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ28-E3/5A FAQ
1.How can I place an order for SMAJ28-E3/5A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ28-E3/5A 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 SMAJ28-E3/5A reliable?
The price and inventory of SMAJ28-E3/5A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ28-E3/5A is usually 5 days.
3.What payment methods are accepted for SMAJ28-E3/5A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ28-E3/5A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ28-E3/5A?
SMAJ28-E3/5A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ28-E3/5A 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 SMAJ28-E3/5A?
For technical support, including SMAJ28-E3/5A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ28-E3/5A requirements.
6.How does Aetrix verify that SMAJ28-E3/5A is sourced from the original manufacturer or authorized distributors?
All SMAJ28-E3/5A 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 SMAJ28-E3/5A meets industry standards.
7.What is the process for return or replacement of SMAJ28-E3/5A?
All SMAJ28-E3/5A units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ28-E3/5A, 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 SMAJ28-E3/5A part is unused and in its original packaging.
Return procedure for SMAJ28-E3/5A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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