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Alpha & Omega Semiconductor Inc. SMDJ28A
- Part No.:
- SMDJ28A
- Manufacturer:
- Alpha & Omega Semiconductor Inc.
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SMDJ28A.pdf
- Description:
- 1CH 28V UNIDIRECTIONAL 3000W SMD
- Quantity:
- Payment:
- Shipping:
Inventory:8,696
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Product details
Overview
SMDJ28A from Alpha & Omega Semiconductor is a unidirectional transient voltage suppressor (TVS) diode designed for high-energy surge protection in DC power lines and signal interfaces. It features a 28.0 V reverse standoff voltage (VRWM), 31.1–34.4 V breakdown voltage (VBR) at 1 mA, 45.4 V maximum clamping voltage at 66.1 A peak pulse current, and 3000 W peak pulse power dissipation on a 10/1000 µs waveform - deployed in industrial motor drives to protect IGBT gate drivers from inductive switching transients.
For engineers reviewing the SMDJ28A datasheet, pinout, applications, or equivalent options, key selection criteria include clamping voltage margin relative to protected IC VDD rails, thermal resistance (RθJL = 15 °C/W), unidirectional polarity confirmation, and DO-214AB package compatibility with automated SMT placement and reflow profiles up to 260 °C.
Technical Context
The SMDJ28A operates as a silicon avalanche diode that enters controlled breakdown above its specified VRWM, diverting transient energy to ground while limiting voltage across downstream components. Its glass-passivated junction ensures stable VBR tolerance and low leakage (≤2.0 µA @ 28.0 V), and its 1.0 ps typical response time enables suppression of fast-rising ESD and lightning-induced surges before sensitive circuitry is stressed.
Mounted on 8.0 mm × 8.0 mm copper pads per terminal, the device delivers 3000 W peak pulse power handling with thermal resistance of 15 °C/W junction-to-lead and 75 °C/W junction-to-ambient. Its MSL1 rating and matte tin lead-free plating support robust, high-yield surface-mount assembly without solderability degradation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 28.0 V - Maximum continuous reverse operating voltage before clamping begins; sets minimum system rail margin for reliable standby operation. |
| VBR @ IT=1 mA | 31.1–34.4 V - Confirmed avalanche onset range; defines threshold for transient conduction and must exceed VRWM by ≥11% for design margin. |
| Vc @ IPPM | 45.4 V - Clamped voltage at 66.1 A peak pulse; determines maximum stress imposed on protected load during worst-case 10/1000 µs surge. |
| PPPM | 3000 W - Peak pulse power rating on standard 10/1000 µs waveform; validates suitability for IEC 61000-4-5 Level 4 (4 kV) surge testing. |
| TJ max | +150 °C - Maximum junction temperature; enables operation in under-hood automotive or enclosed industrial enclosures without derating below full power. |
| Polarity | Unidirectional - Cathode-banded configuration; requires correct orientation in series with positive supply rail to clamp negative transients to ground. |
| Package | DO-214AB (SMC J-Bend) - Standardized surface-mount outline with J-bent leads; supports 3000 pcs/reel tape-and-reel delivery and automated pick-and-place. |
Pinout & Package
DO-214AB (SMC J-Bend) package: molded plastic case with J-bent terminals; cathode indicated by color band; terminals solderable per MIL-STD-750 Method 2026; meets UL 94V-0 flammability rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Transient return path | Connected to ground or low-impedance return plane; carries full IPPM during clamping event; requires low-inductance layout. |
| Cathode | Protected line interface | Connected to DC rail or signal line being protected; polarity marking (band) must align with positive supply direction for unidirectional operation. |
Key Features
| Feature | Design Value |
|---|---|
| Fast response time | Typically <1.0 ps - Enables clamping before ESD or lightning-induced transients propagate into IC inputs, critical for USB, CAN, and RS-485 interfaces. |
| Low profile SMT package | DO-214AB footprint - Saves board space vs. axial-leaded TVS; compatible with standard SMC land patterns and reflow profiles up to 260 °C peak. |
| High surge current capability | 66.1 A IPPM - Supports repeated 10/1000 µs surges without degradation when mounted on 8 mm × 8 mm copper pads. |
| Stable temperature coefficient | ΔVBR = 0.1% × VBR × ΔT - Predictable VBR drift over -55°C to +150°C ambient; simplifies margin analysis across extended temperature ranges. |
| UL 94V-0 flammability | Plastic housing self-extinguishing - Meets safety requirements for enclosed power supplies and industrial control cabinets. |
Applications
| Industrial Motor Drives | Automotive Body Control Modules |
|---|---|
Use Scenario: Protecting gate driver ICs from inductive kickback during IGBT/MOSFET turn-off in 24 V DC bus inverters. IC Role / Device Role: Unidirectional TVS placed between gate driver output and power ground to clamp negative voltage spikes. Use Value: Limits gate-source voltage to ≤45.4 V, preventing gate oxide rupture in SiC or high-speed MOSFET drivers operating near 28 V nominal rails. | Use Scenario: Suppressing load dump transients on LIN bus nodes during battery disconnect events in 12 V vehicle networks. IC Role / Device Role: Unidirectional TVS connected between LIN transceiver VCC pin and chassis ground. Use Value: Clamps 12 V rail to 45.4 V during 35 V/100 ms load dump, maintaining transceiver functionality without latch-up or damage. |
| Telecom Power Feeds | Renewable Energy Inverters |
Use Scenario: Safeguarding PoE (Power over Ethernet) PSE controller ICs from induced surges on 48 V DC feed lines. IC Role / Device Role: Unidirectional TVS installed at PSE output stage before magnetics, referenced to local ground. Use Value: Withstands 3000 W surges while holding clamped voltage below 50 V, preserving IEEE 802.3af/at compliance margins. | Use Scenario: Protecting MPPT controller inputs from lightning-induced surges on PV string monitoring lines in solar farms. IC Role / Device Role: Unidirectional TVS placed across differential voltage sense inputs referenced to system ground. Use Value: Maintains ≤2.0 µA leakage at 28 V, ensuring minimal impact on high-impedance voltage measurement accuracy while suppressing >6 kV transients. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SAC28 | Same VRWM (28 V), but lower PPPM (1500 W); Vc = 48.4 V @ 31.0 A; DO-214AC (SMA) package. | Lower surge capacity limits use to sub-IEC 61000-4-5 Level 3 environments; smaller SMA footprint reduces thermal mass. | Select SAC28 only where board space is constrained and surge threat level is limited to 2 kV contact discharge. |
| 1.5KE28A | Same VRWM (28 V), but axial-leaded DO-201AD package; Vc = 43.0 V @ 69.8 A; higher RθJA (100 °C/W). | Requires through-hole assembly and manual soldering; less suitable for high-volume SMT production or vibration-prone environments. | Choose 1.5KE28A only for legacy designs with existing DO-201AD footprints and no reflow process capability. |
Compared with SAC28 and 1.5KE28A, the SMDJ28A delivers 100% higher peak pulse power (3000 W), superior thermal performance (RθJL = 15 °C/W), and full SMT manufacturability - making it the preferred choice for new industrial and automotive designs requiring IEC 61000-4-5 Level 4 compliance and automated assembly.
Availability
SMDJ28A is available at Aetrix Electronics and suitable for industrial motor drives, automotive body control modules, telecom power feeds, and renewable energy inverters requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant green packaging.
Supply support for SMDJ28A 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
Alpha & Omega Semiconductor (AOS) is a fabless power semiconductor company specializing in high-efficiency MOSFETs, IGBTs, and protection devices for power conversion and management systems.
The SMDJ series is part of AOS's transient voltage suppressor product line, engineered specifically for high-power, surface-mount surge protection in harsh industrial and automotive environments where reliability under repetitive surge stress is critical.
FAQ
What is the maximum clamping voltage of the SMDJ28A under a 10/1000 µs surge?
The SMDJ28A has a maximum clamping voltage (VC) of 45.4 V when subjected to its rated peak pulse current of 66.1 A on a 10/1000 µs waveform. This value is measured per JEDEC standards and defines the upper voltage limit imposed on protected circuitry during worst-case transient events. The SMDJ28A maintains this clamping performance consistently across its operating temperature range of –55°C to +150°C.
Is the SMDJ28A suitable for bidirectional surge protection?
No, the SMDJ28A is a unidirectional TVS diode, intended for clamping only negative-going transients relative to its cathode connection. For bidirectional protection, the SMDJ28CA variant must be used - it provides symmetrical clamping in both polarities. The SMDJ28A's cathode band marking and electrical specifications apply exclusively to unidirectional operation, and incorrect use in a bidirectional configuration may result in failure to suppress positive transients.
What is the thermal resistance specification for the SMDJ28A, and how does it affect PCB layout?
The SMDJ28A has a typical junction-to-lead thermal resistance (RθJL) of 15 °C/W and junction-to-ambient (RθJA) of 75 °C/W when mounted on 8.0 mm × 8.0 mm copper pads per terminal. To achieve rated 3000 W pulse power, the PCB must provide adequate copper area and thermal vias to dissipate heat during repetitive surges. Reducing pad size or omitting thermal relief increases junction temperature and risks parametric shift or failure. The SMDJ28A's RθJL value confirms efficient heat transfer to the PCB leads, enabling reliable operation in compact layouts.
Does the SMDJ28A meet lead-free and RoHS compliance requirements?
Yes, the SMDJ28A is a certified AOS Green Product: it is lead-free, RoHS compliant, and halogen-free per IEC 61249-2-21. Its matte tin lead finish meets J-STD-020 MSL1 moisture sensitivity level and withstands peak reflow temperatures up to 260 °C. The device also complies with UL 94V-0 flammability standards, confirming safe operation in enclosed equipment. Documentation of compliance is available in AOS's Green Policy document (aospdf.com/media/AOSGreenPolicy.pdf).
How does the SMDJ28A's response time compare to standard Zener diodes, and why does it matter?
The SMDJ28A exhibits a typical response time of less than 1.0 ps - significantly faster than conventional Zener diodes (typically >1 ns). This ultrafast reaction enables the SMDJ28A to begin clamping before most ESD and lightning-induced transients fully develop, preventing voltage overshoot from reaching sensitive downstream ICs. In practice, this means the SMDJ28A can protect high-speed interfaces like CAN FD or USB 2.0 without adding signal distortion or timing skew, unlike slower alternatives that allow damaging voltage excursions to occur prior to conduction.
SMDJ28A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Alpha & Omega Semiconductor Inc.
- Package/Case:
- DO-214AB, SMC
- Series:
- -
- 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):
- 66.1A
- Power - Peak Pulse:
- 3000W (3kW)
- 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-214AB
SMDJ28A FAQ
1.How can I place an order for SMDJ28A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMDJ28A 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 SMDJ28A reliable?
The price and inventory of SMDJ28A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMDJ28A is usually 5 days.
3.What payment methods are accepted for SMDJ28A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMDJ28A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMDJ28A?
SMDJ28A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMDJ28A 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 SMDJ28A?
For technical support, including SMDJ28A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMDJ28A requirements.
6.How does Aetrix verify that SMDJ28A is sourced from the original manufacturer or authorized distributors?
All SMDJ28A 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 SMDJ28A meets industry standards.
7.What is the process for return or replacement of SMDJ28A?
All SMDJ28A units undergo pre-shipment inspection (PSI). If there is an issue with SMDJ28A, 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 SMDJ28A part is unused and in its original packaging.
Return procedure for SMDJ28A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMDJ28A Tags
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