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Vishay General Semiconductor - Diodes Division SMAJ28CAHE3_A/H
- Part No.:
- SMAJ28CAHE3_A/H
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ28CAHE3_A/H.pdf
- Description:
- TVS DIODE 28VWM 45.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:9,215
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Product details
Overview
SMAJ28CAHE3_A/H from Vishay General Semiconductor is a bidirectional transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, designed for clamping voltage transients on signal and power lines. It features a 28 V stand-off voltage (VWM), 31.1–34.4 V breakdown voltage (VBR) at 1 mA, 45.4 V maximum clamping voltage (VC) at 8.8 A peak pulse current (IPPM), and 400 W peak pulse power (10/1000 μs waveform). It is AEC-Q101 qualified and used to protect MOSFETs, ICs, and sensor signal lines in automotive and industrial electronics.
For engineers reviewing the SMAJ28CAHE3_A/H datasheet, SMAJ28CAHE3_A/H pinout, SMAJ28CAHE3_A/H application, or SMAJ28CAHE3_A/H equivalent, key selection criteria include bidirectional clamping capability, 28 V working voltage compatibility with 3.3 V/5 V/12 V rail protection, AEC-Q101 qualification status, thermal resistance (RθJA = 120 °C/W), and UL 497B recognition for surge protector classification.
Technical Context
This bidirectional TVS diode operates symmetrically across both polarities, enabling robust protection against positive and negative transients without polarity sensitivity. Its glass-passivated junction ensures stable breakdown characteristics and low leakage (<1 μA at VWM), while the low incremental surge resistance supports fast energy dissipation during ESD or lightning-induced surges.
The device is rated for 400 W peak pulse power (10/1000 μs) up to 78 V and derates to 300 W above that threshold. It meets MSL Level 1 per J-STD-020 with 260 °C reflow peak temperature tolerance and is qualified to AEC-Q101 for automotive under-hood and infotainment applications.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 28 V - Maximum continuous reverse operating voltage before clamping begins; matches 24 V nominal systems with margin. |
| VBR min/max | 31.1 V / 34.4 V at 1 mA - Confirmed breakdown range ensures reliable turn-on within spec under production tolerances. |
| VC @ IPPM | 45.4 V at 8.8 A - Clamping voltage limits downstream component stress during 10/1000 μs surge events. |
| PPPM | 400 W (≤78 V), 300 W (>78 V) - Peak pulse power rating defines transient energy absorption capacity per standard waveform. |
| ID @ VWM | <1 μA - Ultra-low reverse leakage preserves signal integrity and minimizes standby power loss. |
| TJ max | +150 °C - Maximum junction temperature enables operation in high-ambient environments such as engine control units. |
| RθJA | 120 °C/W - Thermal resistance determines self-heating under sustained power dissipation; requires minimum 5.0 mm × 5.0 mm copper pads. |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, low-profile case with matte tin-plated leads solderable per J-STD-002. Bidirectional construction means no polarity marking; both terminals are electrically symmetrical.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode/Cathode (symmetrical) | Transient conduction path | Both terminals serve identical roles; bidirectional clamping occurs regardless of voltage polarity applied. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated reliability for automotive applications including engine control, body electronics, and ADAS sensor interfaces. |
| UL 497B recognition (QVGQ2) | Meets Underwriters Laboratory requirements for telecom and industrial surge protector classification. |
| 400 W peak pulse power (10/1000 μs) | Handles IEC 61000-4-5 Level 4 surge events (4 kV line-to-line) when properly mounted on 5 mm × 5 mm copper pads. |
| Low clamping ratio (VC/VBR ≈ 1.42) | Minimizes overvoltage exposure to protected ICs-critical for 3.3 V logic and analog front-ends. |
| MSL Level 1, 260 °C peak reflow | Enables standard SMT assembly without moisture sensitivity concerns or baking requirements. |
Applications
| Automotive Sensor Protection | Industrial PLC I/O Protection |
|---|---|
|
Use Scenario: Protecting CAN/LIN bus transceivers and analog sensor inputs (e.g., pressure, temperature) from load dump and ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Bidirectional clamping element placed directly at connector entry point to shunt transients before reaching signal conditioning circuitry. Use Value: Maintains signal fidelity under 12 V/24 V system transients while meeting AEC-Q101 lifetime requirements. |
Use Scenario: Safeguarding digital input modules in programmable logic controllers exposed to relay coil flyback and motor drive noise. IC Role / Device Role / Timing Role: Fast-response voltage clamp on 24 V DC input lines to prevent false triggering and latch-up in microcontroller GPIOs. Use Value: Limits induced voltage to ≤45.4 V during 10/1000 μs surges, ensuring safe operation of 3.3 V or 5 V level-shifted logic. |
| Telecom Line Interface | Consumer Power Adapter Input |
|
Use Scenario: Secondary-side transient suppression on Ethernet PHY power rails and RS-485 data lines in base station equipment. IC Role / Device Role / Timing Role: Standoff-rated TVS placed between isolated DC-DC output and interface IC to absorb coupled surges from field wiring. Use Value: Provides UL 497B-compliant protection with <1 μA leakage-preserving low-power sleep modes in always-on devices. |
Use Scenario: Input-stage surge protection on AC-DC adapter secondary outputs (e.g., 5 V, 12 V) feeding USB hubs or smart home controllers. IC Role / Device Role / Timing Role: Primary clamping device after rectification but before linear regulator or buck converter input. Use Value: Absorbs 400 W surges without degradation, supporting EN 61000-4-5 compliance in cost-sensitive consumer designs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ28CA-M3 | Halogen-free, RoHS-compliant, same electrical specs and AEC-Q101 qualification; differs only in plating chemistry (no HE3 suffix). | No functional difference in surge performance or thermal behavior; suitable where halogen-free materials are mandated. | Select SMAJ28CA-M3 if halogen-free compliance is required by OEM material declaration standards. |
| SMBJ28CAHE3_A/H | Same VWM/VBR/VC ratings but in larger SMB (DO-214AA) package; higher RθJA (90 °C/W vs. 120 °C/W) and 600 W PPPM rating. | Better thermal handling and higher surge margin, but requires larger PCB footprint and may not fit space-constrained layouts. | Choose SMBJ28CAHE3_A/H only when 600 W surge capability or improved thermal derating is needed and board area permits. |
Compared with SMAJ28CAHE3_A/H, SMAJ28CA-M3 offers identical protection performance with halogen-free construction, while SMBJ28CAHE3_A/H trades compact size for higher power handling and lower thermal resistance-making it preferable for high-reliability industrial designs where layout allows.
Availability
SMAJ28CAHE3_A/H is available at Aetrix Electronics and suitable for automotive ECUs, industrial PLCs, telecom interface modules, and consumer power adapters requiring stable component supply and AEC-Q101 assurance.
Supply support for SMAJ28CAHE3_A/H 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, and protection devices with emphasis on reliability, automotive qualification, and application-specific performance.
The SMAJ series is engineered for high-energy transient suppression in harsh environments, targeting automotive, industrial, and telecom applications where robustness, low leakage, and standardized mounting are critical.
FAQ
What is the clamping voltage of SMAJ28CAHE3_A/H at its rated peak pulse current?
The SMAJ28CAHE3_A/H has a maximum clamping voltage (VC) of 45.4 V at 8.8 A peak pulse current (IPPM), measured under the standard 10/1000 μs waveform. This value ensures protected downstream components remain below their absolute maximum voltage ratings during surge events. The clamping performance is verified across production lots and specified in the Vishay datasheet Document Number 88390.
Is SMAJ28CAHE3_A/H suitable for automotive applications?
Yes, SMAJ28CAHE3_A/H is AEC-Q101 qualified and explicitly designated for automotive use with the "HE3" suffix indicating RoHS-compliant and AEC-Q101 qualified construction. It is deployed in engine control units, body control modules, and sensor interfaces where immunity to load dump and ISO 7637-2 transients is required. The device's -55 °C to +150 °C operating range and MSL Level 1 rating further support under-hood deployment.
How does the bidirectional configuration of SMAJ28CAHE3_A/H affect its circuit placement?
The bidirectional configuration of SMAJ28CAHE3_A/H eliminates polarity constraints-both terminals are functionally identical, so no cathode band orientation is needed during placement. This simplifies layout on differential lines (e.g., CAN, RS-485) or unidirectional rails where reverse transients may occur. Unlike unidirectional TVS diodes, SMAJ28CAHE3_A/H provides symmetrical clamping in either direction without requiring external series diodes or dual-device arrangements.
What is the thermal resistance of SMAJ28CAHE3_A/H, and how does it impact PCB layout?
SMAJ28CAHE3_A/H has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W when mounted on the minimum recommended 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal. To maintain safe junction temperatures during repetitive surges or elevated ambient conditions, designers must adhere to this pad layout. Reducing pad size increases thermal impedance and risks exceeding the +150 °C maximum junction temperature, especially under sustained power dissipation.
Does SMAJ28CAHE3_A/H meet any safety certifications for surge protection?
Yes, SMAJ28CAHE3_A/H carries Underwriters Laboratory (UL) Recognition under file number E136766 for both unidirectional and bidirectional configurations, compliant with UL 497B for telecommunications primary protectors. This certification validates its suitability in safety-critical surge protection circuits across telecom, industrial, and automotive applications-providing assurance beyond basic parametric compliance.
SMAJ28CAHE3_A/H Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AC, SMA
- Series:
- TransZorb®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 28V
- Voltage - Breakdown (Min):
- 31.1V
- Voltage - Clamping (Max) @ Ipp:
- 45.4V
- Current - Peak Pulse (10/1000µs):
- 8.8A
- 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)
SMAJ28CAHE3_A/H FAQ
1.How can I place an order for SMAJ28CAHE3_A/H through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ28CAHE3_A/H 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 SMAJ28CAHE3_A/H reliable?
The price and inventory of SMAJ28CAHE3_A/H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ28CAHE3_A/H is usually 5 days.
3.What payment methods are accepted for SMAJ28CAHE3_A/H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ28CAHE3_A/H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ28CAHE3_A/H?
SMAJ28CAHE3_A/H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ28CAHE3_A/H 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 SMAJ28CAHE3_A/H?
For technical support, including SMAJ28CAHE3_A/H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ28CAHE3_A/H requirements.
6.How does Aetrix verify that SMAJ28CAHE3_A/H is sourced from the original manufacturer or authorized distributors?
All SMAJ28CAHE3_A/H 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 SMAJ28CAHE3_A/H meets industry standards.
7.What is the process for return or replacement of SMAJ28CAHE3_A/H?
All SMAJ28CAHE3_A/H units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ28CAHE3_A/H, 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 SMAJ28CAHE3_A/H part is unused and in its original packaging.
Return procedure for SMAJ28CAHE3_A/H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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