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Vishay General Semiconductor - Diodes Division SMAJ28AHM3_A/H
- Part No.:
- SMAJ28AHM3_A/H
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ28AHM3_A/H.pdf
- Description:
- TVS DIODE 28VWM 45.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:4,115
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Product details
Overview
SMAJ28AHM3_A/H from Vishay General Semiconductor is a unidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMA (DO-214AC) package, designed for clamping voltage transients on power and signal 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), commonly deployed to protect MOSFET gates and microcontroller I/O in automotive body electronics.
For engineers reviewing the SMAJ28AHM3_A/H datasheet, SMAJ28AHM3_A/H pinout, SMAJ28AHM3_A/H application, or SMAJ28AHM3_A/H equivalent, key selection criteria include verified clamping performance under 10/1000 μs surge, unidirectional polarity with cathode band marking, AEC-Q101 qualification status, and compatibility with automated SMT placement on 0.2" × 0.2" copper pads.
Technical Context
This TVS diode operates as a fast-acting shunt protector: when reverse voltage exceeds VBR, it avalanches to clamp transient energy away from downstream circuitry. Its glass-passivated junction ensures stable leakage (<1.0 μA at VWM) and low incremental surge resistance, enabling consistent clamping across repetitive surges.
The device is rated for 150 °C max junction temperature and exhibits a +0.098 %/°C temperature coefficient of VBR - critical for thermal stability in under-hood automotive environments. Its MSL Level 1 rating (260 °C peak reflow) and matte tin-plated leads comply with J-STD-002 solderability standards.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 28 V - maximum continuous reverse operating voltage before significant leakage begins; defines safe operating margin below clamping threshold |
| VBR (min/max) | 31.1 V / 34.4 V at 1 mA - guaranteed avalanche initiation range; ensures predictable turn-on across process and temperature |
| VC @ IPPM | 45.4 V at 8.8 A - clamped voltage during 10/1000 μs surge; determines maximum stress imposed on protected IC or MOSFET |
| PPPM | 400 W - peak pulse power handling per 10/1000 μs waveform on specified 0.2" × 0.2" copper pads; defines single-event surge robustness |
| ID @ VWM | ≤1.0 μA - reverse leakage at stand-off voltage; ensures minimal quiescent power loss and signal integrity on high-impedance lines |
| TJ max. | +150 °C - maximum junction temperature; enables operation in under-hood automotive and industrial ambient conditions |
| AEC-Q101 | Qualified - validated for automotive-grade reliability including temperature cycling, HTRB, and ESD; required for body control modules and lighting drivers |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, low-profile case with matte tin-plated leads. Cathode identified by a visible band on the body end.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to ground or lower-potential rail in unidirectional protection configuration; carries surge current during clamping |
| Cathode | Reverse-biased clamping terminal | Connected to protected line (e.g., 24 V supply or CAN_H); avalanche conduction initiates here when V > VBR |
Key Features
| Feature | Design Value |
|---|---|
| 400 W peak pulse power (10/1000 μs) | Enables reliable suppression of ISO 7637-2 Pulse 1/2a/5a transients in 12 V/24 V automotive systems without derating |
| AEC-Q101 qualified (HM3 suffix) | Confirms compliance with automotive stress tests including HTGB, TC, and AC-H3TRB - required for OEM Tier 1 BOM acceptance |
| MSL Level 1, 260 °C peak reflow | Supports standard lead-free SMT assembly without moisture sensitivity concerns or baking requirements |
| Glass passivated junction | Delivers stable VBR and low leakage over lifetime, even under humidity and thermal cycling stress |
| Halogen-free, RoHS-compliant (HM3) | Fulfills EU ELV and customer green procurement mandates without compromising electrical performance |
Applications
| Automotive Body Control Module | Industrial PLC Digital Input |
|---|---|
Use Scenario: Protecting 24 V supply rails and switch inputs against load dump and inductive kickback in door module ECUs. IC Role / Device Role / Timing Role: Unidirectional shunt TVS placed between 24 V rail and chassis ground to clamp transients before they reach MCU power pins. Use Value: Limits rail voltage to ≤45.4 V during 100 A/50 ms load dump events, preventing brownout or latch-up in 3.3 V logic supplies derived via LDO. |
Use Scenario: Safeguarding 24 V digital input channels on programmable logic controllers exposed to field wiring surges. IC Role / Device Role / Timing Role: Standoff-clamp TVS on each optocoupler input leg to absorb induced transients from adjacent motor cables. Use Value: Maintains <1.0 μA leakage at 24 V, preserving input threshold accuracy while clamping 8.8 A surges within 1 ns response time. |
| Automotive LED Headlamp Driver | Telecom Power Interface |
Use Scenario: Shielding high-side MOSFET gate drivers from switching noise and relay bounce in adaptive front-lighting systems. IC Role / Device Role / Timing Role: Local TVS mounted directly at gate driver output to suppress dv/dt-induced false triggering. Use Value: Clamps gate-source voltage to ≤45.4 V during 10/1000 μs surges, preventing MOSFET avalanche failure and ensuring PWM fidelity. |
Use Scenario: Protecting 48 V DC power feed inputs on telecom base station remote radio units from lightning-induced surges. IC Role / Device Role / Timing Role: First-stage unidirectional TVS on primary DC input before bulk capacitor and DC/DC converter. Use Value: Handles 400 W pulses without degradation, reducing need for secondary MOV-based protection and minimizing board space. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ28AHE3_A/H | Same electrical specs and AEC-Q101 qualification, but RoHS-compliant with lead-free (non-halogen-free) plating | Acceptable where halogen-free mandate is not enforced; identical layout and thermal behavior | Select SMAJ28AHM3_A/H only when halogen-free compliance is contractually required |
| SMBJ28A-HM3 | Higher 600 W PPPM rating in larger SMB (DO-214AA) package; same VWM/VBR/VC but 12.5 A IPPM | Better suited for higher-energy transients (e.g., ISO 16750-2 long-duration pulses); requires larger PCB footprint | Choose SMBJ28A-HM3 when system-level testing shows 400 W insufficient; otherwise SMAJ28AHM3_A/H optimizes space and cost |
Compared with SMAJ28AHE3_A/H, SMAJ28AHM3_A/H adds halogen-free construction without sacrificing AEC-Q101 or clamping performance; versus SMBJ28A-HM3, it trades 50 % higher pulse power for 30 % smaller footprint and lower thermal resistance to ambient.
Availability
SMAJ28AHM3_A/H is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC I/O protection, and telecom DC power interface designs requiring stable component supply, halogen-free compliance, and AEC-Q101 validation.
Supply support for SMAJ28AHM3_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 qualification.
The SMAJ series was engineered specifically for surface-mount transient suppression in space-constrained automotive and industrial systems, balancing high pulse power density, fast response, and manufacturability.
FAQ
What is the clamping voltage of SMAJ28AHM3_A/H at its rated peak pulse current?
The SMAJ28AHM3_A/H has a maximum clamping voltage (VC) of 45.4 V at 8.8 A peak pulse current (IPPM), measured under the standardized 10/1000 μs waveform condition. This value defines the upper voltage limit imposed on protected circuitry during surge events and is confirmed in Vishay's datasheet Document Number 88390, page 2. The clamping performance remains stable across temperature due to its +0.098 %/°C VBR coefficient.
Is SMAJ28AHM3_A/H qualified for automotive applications?
Yes, SMAJ28AHM3_A/H is AEC-Q101 qualified, as indicated by the "HM3" suffix and confirmed in the Vishay datasheet revision 09-Jan-2024. This qualification covers stress tests including high-temperature reverse bias, temperature cycling, and unbiased highly accelerated stress testing - making it suitable for use in automotive body control modules, lighting drivers, and infotainment power supplies.
What does the "HM3" suffix signify in SMAJ28AHM3_A/H?
The "HM3" suffix in SMAJ28AHM3_A/H denotes halogen-free, RoHS-compliant construction with matte tin-plated leads, meeting JESD201 Class 2 whisker resistance. It also confirms AEC-Q101 qualification. This distinguishes it from "HE3" (RoHS-compliant, AEC-Q101, but not halogen-free) and "E3" (commercial-grade, RoHS-compliant only).
How does SMAJ28AHM3_A/H differ from SMAJ28A-E3/61?
SMAJ28AHM3_A/H is halogen-free, AEC-Q101 qualified, and supplied in 7" tape-and-reel (1800 pcs), whereas SMAJ28A-E3/61 is RoHS-compliant but not halogen-free or automotive-qualified, and uses the same packaging. Electrically, both share identical VWM (28 V), VBR (31.1–34.4 V), and VC (45.4 V), but only SMAJ28AHM3_A/H meets automotive OEM green and reliability mandates.
What is the thermal resistance of SMAJ28AHM3_A/H from junction to ambient?
The typical thermal resistance from junction to ambient (RθJA) for SMAJ28AHM3_A/H is 120 °C/W when mounted on the minimum recommended pad layout (0.2" × 0.2" copper pads per terminal), per Vishay datasheet page 3. This value is critical for calculating junction temperature rise under sustained power dissipation and must be used with the 3.3 W steady-state power rating (PD) for thermal design validation.
SMAJ28AHM3_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:
- Telecom
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ28AHM3_A/H FAQ
1.How can I place an order for SMAJ28AHM3_A/H through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ28AHM3_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 SMAJ28AHM3_A/H reliable?
The price and inventory of SMAJ28AHM3_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 SMAJ28AHM3_A/H is usually 5 days.
3.What payment methods are accepted for SMAJ28AHM3_A/H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ28AHM3_A/H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ28AHM3_A/H?
SMAJ28AHM3_A/H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ28AHM3_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 SMAJ28AHM3_A/H?
For technical support, including SMAJ28AHM3_A/H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ28AHM3_A/H requirements.
6.How does Aetrix verify that SMAJ28AHM3_A/H is sourced from the original manufacturer or authorized distributors?
All SMAJ28AHM3_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 SMAJ28AHM3_A/H meets industry standards.
7.What is the process for return or replacement of SMAJ28AHM3_A/H?
All SMAJ28AHM3_A/H units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ28AHM3_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 SMAJ28AHM3_A/H part is unused and in its original packaging.
Return procedure for SMAJ28AHM3_A/H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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