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STMicroelectronics SMA6J28A-TR
- Part No.:
- SMA6J28A-TR
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMA6J28A-TR.pdf
- Description:
- TVS DIODE 28VWM 51.6VC SMA
- Quantity:
- Payment:
- Shipping:
Inventory:27,935
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Product details
Overview
SMA6J28A-TR from STMicroelectronics is a unidirectional 600 W transient voltage suppression diode with a standoff voltage of 28 V, clamping voltage of 44.0 V at 13.8 A (10/1000 µs), and low leakage current (0.2 µA at 25 °C). It protects DC power rails and I/O lines in industrial control systems against ESD per IEC 61000-4-2 (30 kV contact/air) and fast transients per IEC 61000-4-4 (4 kV).
For engineers reviewing the SMA6J28A-TR datasheet, SMA6J28A-TR pinout, SMA6J28A-TR application, or SMA6J28A-TR equivalent, this TVS diode is selected for high-reliability 24 V system surge protection where junction temperature up to 175 °C, low dynamic resistance (0.697 Ω), and IPC7531-compliant SMA footprint are required.
Technical Context
This unidirectional TVS operates as a voltage-clamped shunt protector: it remains high-impedance below 28 V (VRM), breaks down sharply at 31.1–34.4 V (VBR min–max), and limits surge energy by diverting current to ground when transients exceed VBR. Its planar silicon construction ensures stable leakage and thermal performance across -55 °C to +175 °C.
The device complies with JEDEC DO-214AC (SMA) mechanical outline and UL94 V0 resin housing. It achieves 600 W peak pulse power (10/1000 µs) and 4 kW (8/20 µs), with clamping voltage tightly bounded by dynamic resistance (0.697 Ω) and temperature coefficient (10⁻⁴/°C).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standoff Voltage (VRM) | 28 V - Maximum continuous reverse operating voltage before breakdown begins. |
| Breakdown Voltage (VBR) | 31.1–34.4 V at 1 mA - Confirmed voltage range where device transitions from blocking to clamping mode. |
| Clamping Voltage (VCL) | 44.0 V at 13.8 A (10/1000 µs) - Peak voltage seen by protected circuit during worst-case surge. |
| Peak Pulse Power (PPP) | 600 W (10/1000 µs) - Sustained surge energy handling capability on standard FR4 PCB with recommended copper area. |
| Leakage Current (IRM) | 0.2 µA at 25 °C, 1 µA at 85 °C - Minimal DC loading on 24 V supply rail under normal operation. |
| Dynamic Resistance (RD) | 0.697 Ω - Low impedance during clamping ensures tighter VCL control and reduced voltage overshoot. |
| Junction Temperature Range | -55 °C to +175 °C - Enables deployment in under-hood automotive, industrial motor drives, and outdoor power supplies. |
Pinout & Package
Package: DO-214AC (SMA), JEDEC-registered, UL94 V0 molded epoxy case, matte tin-plated leads, MSL Level 1, compatible with IPC7531 footprint (5.43 mm × 2.63 mm pad pitch).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (marked band) | Surge return path | Connected to system ground; carries full transient current during clamping event. |
| Anode | Protected line connection | Connected to 24 V rail or signal line; voltage referenced to cathode during overvoltage. |
Key Features
| Feature | Design Value |
|---|---|
| IEC 61000-4-2 ESD immunity | 30 kV air/contact discharge - Eliminates need for external ESD filters in industrial HMI and sensor interfaces. |
| Low clamping ratio (VCL/VBR) | 1.27 (44.0 V / 34.4 V max) - Minimizes stress on downstream 30 V-rated ICs in 24 V systems. |
| High-temperature reliability | 175 °C Tj max with <1 µA leakage at 85 °C - Ensures long-term stability in enclosed power converters. |
| JEDEC DO-214AC compliance | Standardized mechanical outline and soldering profile - Enables drop-in replacement and automated assembly compatibility. |
| UL94 V0 flammability rating | Self-extinguishing epoxy housing - Meets safety requirements for industrial equipment enclosures. |
Applications
| Industrial PLC I/O Protection | 24 V DC Power Rail Clamping |
|---|---|
Use Scenario: Digital input modules in programmable logic controllers exposed to inductive kickback from solenoid valves and relay coils. IC Role / Device Role / Timing Role: Unidirectional shunt TVS placed between field-side 24 V input and common ground. Use Value: Limits induced surges to ≤44.0 V, protecting 24 V-rated optocouplers and microcontroller GPIO without derating. |
Use Scenario: Main 24 V supply rail in factory automation controllers subject to load dump and hot-swap transients. IC Role / Device Role / Timing Role: Primary clamping device parallel to bulk capacitor, activated within nanoseconds of overvoltage onset. Use Value: Absorbs 600 W (10/1000 µs) surges while maintaining rail integrity for downstream PMICs and FPGAs. |
| Automotive Body Control Module | RS-485 Transceiver Protection |
Use Scenario: 12/24 V battery-supplied body control units encountering jump-start spikes and alternator load dump. IC Role / Device Role / Timing Role: Standoff-rated TVS on VBAT input, coordinated with upstream fuse and downstream LDO. Use Value: Withstands 175 °C junction temperature and maintains <1 µA leakage at 85 °C ambient, ensuring reliability in engine bay proximity. |
Use Scenario: Half-duplex RS-485 data lines in building management systems subjected to cable ESD events. IC Role / Device Role / Timing Role: Bidirectional-capable unidirectional TVS (anode-to-ground, cathode-to-line) on A/B differential pair. Use Value: Clamps 30 kV ESD pulses to <44 V within 1 ns, preserving signal integrity and preventing transceiver latch-up. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMA6J28AHE3/A/H | Same electrical specs; AEC-Q200 qualified, enhanced moisture sensitivity level (MSL 1), halogen-free. | Required for automotive ECUs where qualification and long-term humidity resistance are mandatory. | Select for automotive-grade deployments requiring PPAP documentation and extended reliability validation. |
| P6SMB28A | Same VRM (28 V), but higher VCL (45.4 V @ 13.3 A), higher RD (0.75 Ω), lower PPP (600 W same, but derated above 85 °C). | Acceptable for commercial-grade 24 V systems with margin >1.4 V between VCL and downstream IC abs max. | Choose when cost sensitivity outweighs 1.4 V clamping margin and high-temp leakage performance. |
Compared with SMA6J28A-TR, SMA6J28AHE3/A/H adds AEC-Q200 qualification and halogen-free compliance for automotive use, while P6SMB28A trades 1.4 V tighter clamping and superior high-temperature leakage for broader commercial availability and lower unit cost.
Availability
SMA6J28A-TR is available at Aetrix Electronics and suitable for industrial PLC I/O protection, 24 V DC power rail clamping, and RS-485 transceiver protection requiring stable component supply, long-lifecycle support, and traceable sourcing.
Supply support for SMA6J28A-TR 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, power, MCU, and sensor solutions for industrial, automotive, and consumer markets.
SMA6JxxA belongs to ST's high-power TVS diode product line, engineered specifically for robust electrostatic and surge protection in harsh-environment industrial and transportation electronics.
FAQ
What is the maximum clamping voltage of SMA6J28A-TR under a 10/1000 µs surge?
The maximum clamping voltage is 44.0 V at 13.8 A for a 10/1000 µs waveform, measured at 25 °C ambient. This value increases with junction temperature at a rate defined by the 10⁻⁴/°C temperature coefficient, reaching ~46.2 V at 125 °C junction temperature.
Can SMA6J28A-TR be used in bidirectional signal line protection?
No - SMA6J28A-TR is unidirectional and conducts only in reverse bias. For bidirectional protection (e.g., RS-485 A/B lines), the SMA6J28CA-TR variant must be used. Using the 'A' version on AC-coupled or floating signals risks forward conduction and failure.
What PCB layout practices maximize surge-handling capability?
Use the IPC7531-recommended SMA footprint with ≥1.64 cm² total copper area under both pads (per Figure 12), minimize trace length between TVS and protected node, and connect cathode directly to solid ground plane - not daisy-chained ground traces - to reduce inductance and maintain clamping performance.
Is SMA6J28A-TR compliant with lead-free reflow standards?
Yes - it supports JEDEC J-STD-020 MSL Level 1 and is qualified for lead-free reflow with peak temperature up to 245 °C (240–245 °C for 2–3 seconds), per ST's documented reflow profile (Figure 21, DS5142 Rev 11).
SMA6J28A-TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AC, SMA
- Series:
- SMA6J, TRANSIL™
- 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:
- 51.6V
- Current - Peak Pulse (10/1000µs):
- 68A (8/20µs)
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 175°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMA6J28A-TR FAQ
1.How can I place an order for SMA6J28A-TR through Aetrix?
Please submit a Request for Quotation (RFQ) for SMA6J28A-TR 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 SMA6J28A-TR reliable?
The price and inventory of SMA6J28A-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMA6J28A-TR is usually 5 days.
3.What payment methods are accepted for SMA6J28A-TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMA6J28A-TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMA6J28A-TR?
SMA6J28A-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMA6J28A-TR 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 SMA6J28A-TR?
For technical support, including SMA6J28A-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMA6J28A-TR requirements.
6.How does Aetrix verify that SMA6J28A-TR is sourced from the original manufacturer or authorized distributors?
All SMA6J28A-TR 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 SMA6J28A-TR meets industry standards.
7.What is the process for return or replacement of SMA6J28A-TR?
All SMA6J28A-TR units undergo pre-shipment inspection (PSI). If there is an issue with SMA6J28A-TR, 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 SMA6J28A-TR part is unused and in its original packaging.
Return procedure for SMA6J28A-TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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