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Vishay General Semiconductor - Diodes Division SMAJ28AHE3_A/H
- Part No.:
- SMAJ28AHE3_A/H
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ28AHE3_A/H.pdf
- Description:
- TVS DIODE 28VWM 45.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
SMAJ28AHE3_A/H from Vishay General Semiconductor is a unidirectional transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, designed for clamping ESD and surge transients on power and signal lines. It features 31.1 V to 34.4 V breakdown voltage (VBR) at 1 mA, 28 V stand-off voltage (VWM), 45.4 V maximum clamping voltage (VC) at 8.8 A peak pulse current, and 400 W peak pulse power rating with 10/1000 μs waveform - used to protect MOSFET gates, microcontroller I/O, and automotive sensor interfaces.
For engineers reviewing the SMAJ28AHE3_A/H datasheet, SMAJ28AHE3_A/H pinout, SMAJ28AHE3_A/H application, or SMAJ28AHE3_A/H equivalent, key selection criteria include unidirectional polarity, AEC-Q101 qualification, 120 °C/W junction-to-ambient thermal resistance, and compatibility with automated SMT placement on 0.2" × 0.2" copper pads.
Technical Context
This TVS diode operates as a voltage-clamping protection device in series with sensitive downstream circuitry, conducting only when reverse voltage exceeds VBR. Its glass-passivated junction ensures stable leakage (<1.0 μA at 28 V) and fast response time (<1.0 ps), enabling suppression of ESD (IEC 61000-4-2) and lightning-induced surges (IEC 61000-4-5).
The SMAJ28AHE3_A/H is rated for repetitive 0.01% duty cycle pulses up to 400 W below 78 V, derating linearly above 25 °C ambient per Fig. 2, with maximum junction temperature of +150 °C and thermal resistance RθJA = 120 °C/W under standard PCB layout conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VBR (min/max) | 31.1 V to 34.4 V at 1 mA - defines precise clamping onset threshold for overvoltage events |
| VWM | 28 V - maximum continuous reverse operating voltage before leakage rises significantly |
| VC @ IPPM | 45.4 V at 8.8 A - clamped voltage seen by protected IC during worst-case 10/1000 μs surge |
| PPPM | 400 W - peak pulse power handling capability with 10/1000 μs waveform, critical for automotive load-dump immunity |
| IFSM | 40 A - surge current rating for 8.3 ms half-sine wave, supports inductive switch-off protection |
| TJ max | +150 °C - enables operation in under-hood automotive environments and industrial enclosures |
| Package | SMA (DO-214AC) - surface-mount package with 0.208" × 0.157" footprint, compatible with J-STD-020 MSL Level 1 reflow |
Pinout & Package
Package: SMA (DO-214AC), molded plastic case with matte tin-plated leads; cathode indicated by band marking on unidirectional devices; meets UL 94 V-0 flammability rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to ground or low-side reference in unidirectional clamp configuration |
| Cathode | Reverse-biased clamping terminal | Connected to protected line (e.g., 24 V supply rail or CAN_H); conducts during overvoltage |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD testing per JESD22-A114 |
| 400 W peak pulse power | Withstands ISO 7637-2 Pulse 1/2a/5a transients without degradation when mounted on 5 mm × 5 mm copper pads |
| Glass passivated junction | Ensures stable VBR tolerance (±5%) and low leakage (<1 μA at VWM) across -55 °C to +150 °C |
| MSL Level 1 | Compatible with standard SMT reflow profiles up to 260 °C peak, eliminating moisture sensitivity handling requirements |
| Low incremental surge resistance | Minimizes VC overshoot during fast-rising transients (e.g., ESD contact discharge), improving system-level immunity |
Applications
| Automotive Body Control Module | Industrial PLC Digital Input |
|---|---|
|
Use Scenario: Protecting 24 V sensor supply lines against load dump and alternator ripple in BCMs. IC Role / Device Role / Timing Role: Unidirectional clamping TVS placed between fused 24 V rail and microcontroller LDO input. Use Value: Limits transient voltage to ≤45.4 V, preventing damage to 3.3 V/5 V logic supplies downstream while maintaining AEC-Q101 compliance. |
Use Scenario: Shielding 24 V digital input channels from field-wiring induced surges in factory automation PLCs. IC Role / Device Role / Timing Role: Front-end transient suppressor on optocoupler input side, before current-limiting resistor. Use Value: Clamps 1 kV/500 A surge (10/1000 μs) to safe levels within 1 ns, preserving input isolation integrity and reducing false triggering. |
| Consumer Appliance Motor Drive | Telecom Power Interface |
|
Use Scenario: Safeguarding gate drivers and MCU pins from inductive kickback during BLDC motor commutation. IC Role / Device Role / Timing Role: Local TVS on half-bridge high-side gate supply rail, adjacent to driver IC. Use Value: Absorbs 400 W spikes without latch-up, enabling robust operation at 20 kHz PWM frequency with minimal board space. |
Use Scenario: Protecting PoE-powered Ethernet PHY interfaces from lightning-induced common-mode surges on RJ45 lines. IC Role / Device Role / Timing Role: Secondary-level TVS on DC bias feed to magnetics, after primary gas discharge tube. Use Value: Provides <100 ps response to fast-rising surges, complementing slower GDTs and ensuring sub-50 V clamping at PHY pins. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ28A-E3/61 | Same electrical specs and SMA package; RoHS-compliant commercial grade without AEC-Q101 qualification | Lacks automotive qualification; suitable for industrial/commercial designs where AEC-Q101 is not mandated | Select when cost sensitivity outweighs automotive qualification requirements and full lifecycle traceability is not required |
| SMBJ28AHE3_A/H | Same VWM/VC/PPPM, but in larger SMB (DO-214AA) package with higher IPPM (12.3 A) and lower RθJA (85 °C/W) | Better thermal performance and surge margin; requires larger PCB area and different pad layout | Choose when higher surge endurance (>400 W) or improved thermal dissipation is needed, accepting larger footprint |
Compared with SMAJ28AHE3_A/H, SMAJ28A-E3/61 offers identical protection performance without automotive qualification, while SMBJ28AHE3_A/H delivers enhanced thermal and surge robustness in a physically larger package - enabling trade-offs between board space, qualification needs, and long-term reliability margins.
Availability
SMAJ28AHE3_A/H is available at Aetrix Electronics and suitable for automotive body electronics, industrial programmable logic controllers, and telecom power interface designs requiring stable component supply with full AEC-Q101 traceability and MSL Level 1 SMT compatibility.
Supply support for SMAJ28AHE3_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, precision, and automotive-grade validation.
The SMAJ series is engineered specifically for robust transient suppression in harsh environments - targeting automotive, industrial, and telecom applications where repeatable clamping, low leakage, and AEC-Q101 compliance are mandatory.
FAQ
What is the breakdown voltage range for SMAJ28AHE3_A/H?
The SMAJ28AHE3_A/H has a guaranteed breakdown voltage (VBR) range of 31.1 V to 34.4 V at 1 mA test current, measured per ANSI/IEEE C62.35 standards. This tight tolerance ensures consistent clamping behavior across production lots and temperature extremes, directly supporting design margin calculations for 24 V automotive systems where VBR must exceed nominal rail voltage while staying below downstream IC absolute maximum ratings. The SMAJ28AHE3_A/H achieves this via glass-passivated junction control and 100% lot testing.
Is SMAJ28AHE3_A/H suitable for automotive applications?
Yes, SMAJ28AHE3_A/H is AEC-Q101 qualified and explicitly designated for automotive use with ordering code suffix "HE3". It undergoes stress testing including high-temperature reverse bias (HTRB), temperature cycling, and ESD per JESD22-A114, and is rated for operation from -55 °C to +150 °C. Its 400 W peak pulse power and 45.4 V clamping voltage meet ISO 7637-2 Pulse 5a requirements for 12 V/24 V systems, making SMAJ28AHE3_A/H appropriate for BCM, ADAS sensor modules, and infotainment power rails.
What is the maximum clamping voltage of SMAJ28AHE3_A/H at rated surge current?
The SMAJ28AHE3_A/H exhibits a maximum clamping voltage (VC) of 45.4 V at its rated peak pulse current (IPPM) of 8.8 A, defined using the standardized 10/1000 μs double-exponential waveform. This value represents the worst-case voltage imposed on protected circuitry during surge events and is validated across temperature and process variations. Designers use this parameter to verify that downstream components - such as 3.3 V or 5 V regulators - remain within their absolute maximum input voltage limits during transient conditions, confirming SMAJ28AHE3_A/H's effectiveness in safeguarding sensitive nodes.
Does SMAJ28AHE3_A/H have polarity marking, and how is it oriented in circuit?
Yes, SMAJ28AHE3_A/H is unidirectional and features a cathode band marking on the package body, aligned with the cathode terminal. In circuit implementation, the cathode connects to the line being protected (e.g., 24 V supply rail), while the anode connects to ground or return path - enabling conduction only during positive transients relative to ground. This orientation ensures proper clamping action without forward conduction during normal operation, and the band marking allows automated optical inspection (AOI) and manual verification during assembly. The SMAJ28AHE3_A/H follows standard DO-214AC polarity conventions used across Vishay's TVS portfolio.
What thermal resistance does SMAJ28AHE3_A/H exhibit under standard mounting conditions?
SMAJ28AHE3_A/H has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W when mounted on 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per JEDEC standards. This value governs temperature rise during sustained power dissipation and influences derating curves above 25 °C ambient. For example, at 25 °C ambient and 3.3 W steady-state power (PD), junction temperature reaches ~330 °C - exceeding rating - confirming that SMAJ28AHE3_A/H is intended for transient-only duty, not continuous dissipation. Its RθJA is optimized for short-pulse energy absorption, not DC thermal management.
SMAJ28AHE3_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:
- 1
- Bidirectional Channels:
- -
- 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)
SMAJ28AHE3_A/H FAQ
1.How can I place an order for SMAJ28AHE3_A/H through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ28AHE3_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 SMAJ28AHE3_A/H reliable?
The price and inventory of SMAJ28AHE3_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 SMAJ28AHE3_A/H is usually 5 days.
3.What payment methods are accepted for SMAJ28AHE3_A/H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ28AHE3_A/H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ28AHE3_A/H?
SMAJ28AHE3_A/H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ28AHE3_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 SMAJ28AHE3_A/H?
For technical support, including SMAJ28AHE3_A/H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ28AHE3_A/H requirements.
6.How does Aetrix verify that SMAJ28AHE3_A/H is sourced from the original manufacturer or authorized distributors?
All SMAJ28AHE3_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 SMAJ28AHE3_A/H meets industry standards.
7.What is the process for return or replacement of SMAJ28AHE3_A/H?
All SMAJ28AHE3_A/H units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ28AHE3_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 SMAJ28AHE3_A/H part is unused and in its original packaging.
Return procedure for SMAJ28AHE3_A/H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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