My Inquiry
My Account
Vishay General Semiconductor - Diodes Division SMAJ28AHM3/I
- Part No.:
- SMAJ28AHM3/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ28AHM3/I.pdf
- Description:
- TVS DIODE 28VWM 45.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:6,882
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SMAJ28AHM3/I 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 in automotive power rail protection and industrial sensor interface circuits.
For engineers reviewing the SMAJ28AHM3/I datasheet, SMAJ28AHM3/I pinout, SMAJ28AHM3/I application, or SMAJ28AHM3/I equivalent, key selection criteria include its AEC-Q101 qualification (HM3 suffix), halogen-free RoHS compliance, 150 °C max junction temperature, low incremental surge resistance, and compatibility with automated SMT placement on 0.2" × 0.2" copper pads.
Technical Context
This TVS diode operates as a unidirectional clamping device, leveraging an avalanche breakdown mechanism to divert transient energy away from sensitive downstream circuitry. Its response time is sub-nanosecond, and it exhibits low dynamic impedance during clamping, enabling effective suppression of fast-rising ESD and inductive switching spikes.
The SMAJ28AHM3/I is rated for repetitive 10/1000 μs surges at 0.01 % duty cycle (400 W up to 78 V; derated to 300 W above), with thermal resistance of 120 °C/W (junction-to-ambient) and 30 °C/W (junction-to-lead), requiring appropriate PCB copper area for sustained power handling.
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 / 34.4 V at 1 mA - Confirmed breakdown threshold range; ensures reliable turn-on within spec across process variation. |
| VC @ IPPM | 45.4 V at 8.8 A - Clamped voltage under standardized 10/1000 μs surge; determines protected circuit's maximum transient exposure. |
| PPPM | 400 W (10/1000 μs) - Peak transient energy absorption capability; supports robust protection against common automotive load-dump events. |
| ID @ VWM | 1.0 μA - Reverse leakage at stand-off voltage; negligible power loss and minimal impact on high-impedance signal paths. |
| TJ max | +150 °C - Maximum junction temperature; enables operation in under-hood automotive environments and industrial enclosures. |
| Package | SMA (DO-214AC) - Standardized surface-mount outline with cathode band marking; compatible with JEDEC J-STD-020 MSL Level 1 reflow. |
Pinout & Package
Package: SMA (DO-214AC), molded plastic case with matte tin-plated leads, UL 94 V-0 rated, polarity indicated by cathode band on unidirectional variants.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side connection terminal | Connected to ground or return path; completes clamping loop when transient exceeds VBR. |
| Cathode | High-side connection terminal | Connected to protected line (e.g., 24 V rail); marked by visible band; reverse-biased during normal operation. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive applications including engine control units and body electronics per stress test requirements. |
| Halogen-free & RoHS-compliant | HM3 suffix confirms compliance with environmental regulations and material restrictions for global OEM supply chains. |
| 400 W peak pulse power | Handles high-energy transients such as ISO 7637-2 Pulse 5a (load dump) without degradation when mounted per recommended pad layout. |
| Fast response time | Sub-nanosecond clamping onset ensures protection of fast-switching MOSFET gates and microcontroller I/O pins. |
| Low clamping ratio (VC/VBR) | ~1.43 (45.4 V / 31.7 V avg) - Minimizes overvoltage stress on protected ICs compared to competing TVS devices. |
Applications
| Automotive Power Rail Protection | Industrial Sensor Interface Protection |
|---|---|
Use Scenario: Protecting 24 V supply lines in vehicle ECUs from load-dump transients (ISO 7637-2 Pulse 5a) and alternator ripple. IC Role / Device Role / Timing Role: Unidirectional clamping TVS placed between battery feed and LDO input, shunting surge current to chassis ground. Use Value: Limits voltage excursion to ≤45.4 V during 8.8 A surge, preventing damage to downstream 36 V-rated regulators and CAN transceivers. | Use Scenario: Safeguarding analog outputs of pressure/temperature sensors connected to PLC analog input modules. IC Role / Device Role / Timing Role: Standoff protection on 4–20 mA current loop or 0–10 V output line, located adjacent to connector entry point. Use Value: Suppresses induced surges from nearby motor drives or relay switching, preserving ADC reference integrity and measurement accuracy. |
| Consumer Power Adapter Input Protection | Telecom DC Power Feed Protection |
Use Scenario: Input-stage surge suppression on universal AC/DC adapters powering USB-C PD devices and smart home hubs. IC Role / Device Role / Timing Role: Primary TVS on secondary-side DC bus (e.g., 12 V or 19 V), upstream of buck converter and USB controller. Use Value: Absorbs 400 W surges from lightning-induced coupling or hot-plug events while maintaining <1 μA leakage at nominal voltage. | Use Scenario: Protection of -48 V DC telecom power feeds entering base station radios and remote radio units (RRUs). IC Role / Device Role / Timing Role: Unidirectional TVS on negative rail, cathode tied to -48 V line, anode grounded, guarding PoE-like distribution infrastructure. Use Value: Withstands repeated 10/1000 μs surges up to 400 W and operates reliably from -55 °C to +150 °C in outdoor cabinet environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ28AHE3/I | Same electrical specs, but RoHS-compliant without halogen-free certification (E3 vs HM3). | Approved for commercial/industrial use; not AEC-Q101 qualified or halogen-free certified. | Select when automotive qualification or halogen-free requirement is not mandated. |
| SMBJ28A-HM3/I | Higher 600 W PPPM rating, larger SMB (DO-214AA) package, same VWM/VBR/VC. | Requires more PCB area; suited for higher-energy transients where 400 W margin is insufficient. | Choose when system-level testing reveals need for >400 W surge headroom or improved thermal dissipation. |
Compared with SMAJ28AHM3/I, SMAJ28AHE3/I lacks AEC-Q101 and halogen-free status but offers identical clamping performance at lower cost, while SMBJ28A-HM3/I provides greater surge capacity in a physically larger footprint-enabling design flexibility based on space, reliability, and environmental compliance priorities.
Availability
SMAJ28AHM3/I is available at Aetrix Electronics and suitable for automotive electronics, industrial sensor systems, and telecom power distribution requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for SMAJ28AHM3/I 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 devices, and optoelectronics with emphasis on reliability, efficiency, and application-specific optimization.
The SMAJ series is engineered for high-reliability transient suppression in harsh environments, targeting automotive, industrial, and communications systems where robustness against ESD, EFT, and surge events is critical.
FAQ
What is the clamping voltage of the SMAJ28AHM3/I under a standard 10/1000 μs surge?
The SMAJ28AHM3/I has a maximum clamping voltage (VC) of 45.4 V when subjected to its rated peak pulse current (IPPM) of 8.8 A using the 10/1000 μs waveform. This value is measured per Figure 1 in the Vishay datasheet 88390 and defines the upper voltage limit imposed on protected circuitry during transient events.
Is the SMAJ28AHM3/I qualified for automotive applications?
Yes, the SMAJ28AHM3/I is AEC-Q101 qualified, as confirmed by the "HM3" suffix and documentation in Vishay's ordering information table (page 3, note 1). This qualification covers stress tests including HTGB, HTRB, TCT, and mechanical shock, making SMAJ28AHM3/I suitable for under-hood and chassis-mounted automotive electronics.
What does the "HM3" suffix indicate for the SMAJ28AHM3/I?
The "HM3" suffix on SMAJ28AHM3/I denotes halogen-free, RoHS-compliant construction with AEC-Q101 qualification. It distinguishes this variant from E3 (RoHS only), HE3 (AEC-Q101 + RoHS), and M3 (halogen-free + RoHS, non-automotive), confirming compliance with both environmental standards and automotive reliability requirements.
Can the SMAJ28AHM3/I be used in bidirectional configurations?
No, the SMAJ28AHM3/I is a unidirectional TVS diode, as indicated by the "A" (not "CA") suffix and cathode band marking. Bidirectional operation requires a part with "CA" suffix (e.g., SMAJ28CA); using SMAJ28AHM3/I in reverse-biased signal paths would result in forward conduction and failure to suppress negative-going transients.
What is the recommended PCB pad layout for optimal thermal performance of the SMAJ28AHM3/I?
Vishay specifies mounting the SMAJ28AHM3/I on 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal to achieve rated 400 W peak pulse power. Smaller pads reduce thermal dissipation and cause premature failure under repeated surges; thermal relief traces should be minimized, and inner-layer copper pours are recommended for enhanced heat spreading.
SMAJ28AHM3/I Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AC, SMA
- Series:
- TransZorb®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- 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/I FAQ
1.How can I place an order for SMAJ28AHM3/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ28AHM3/I 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/I reliable?
The price and inventory of SMAJ28AHM3/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ28AHM3/I is usually 5 days.
3.What payment methods are accepted for SMAJ28AHM3/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ28AHM3/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ28AHM3/I?
SMAJ28AHM3/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ28AHM3/I 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/I?
For technical support, including SMAJ28AHM3/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ28AHM3/I requirements.
6.How does Aetrix verify that SMAJ28AHM3/I is sourced from the original manufacturer or authorized distributors?
All SMAJ28AHM3/I 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/I meets industry standards.
7.What is the process for return or replacement of SMAJ28AHM3/I?
All SMAJ28AHM3/I units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ28AHM3/I, 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/I part is unused and in its original packaging.
Return procedure for SMAJ28AHM3/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ28AHM3/I Tags
-
ESD9B5.0ST5G
onsemi
-
DESD3V3E1BL-7B
Diodes Incorporated
-
ESD5Z3.3T1G
onsemi
-
D5V0H1B2LP-7B
Diodes Incorporated
-
D5V0P1B2LP-7B
Diodes Incorporated
-
DESD5V0U1BA-7
Diodes Incorporated
-
ESD5Z5.0T1G
onsemi
-
DESD5V0U1BB-7
Diodes Incorporated
-
D12V0L1B2LP-7B
Diodes Incorporated
-
PESD2V0Y1BSFYL
Nexperia USA Inc.
-
DF2S5M4CT,L3F
Toshiba Semiconductor and Storage
-
D5V0L1B2WS-7
Diodes Incorporated
Tech Hub
Schmitt triggers use separate rising and falling thresholds to stabilize slow or noisy signals. This guide covers hysteresis, 74HC14 and 74HCT14 selection, comparator calculations, RC oscillators and p…
Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
