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STMicroelectronics SMCJ28A-TR
- Part No.:
- SMCJ28A-TR
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SMCJ28A-TR.pdf
- Description:
- TVS DIODE 28VWM 59VC SMC
- Quantity:
- Payment:
- Shipping:
Inventory:7,866
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Product details
Overview
SMCJ28A-TR from STMicroelectronics is a unidirectional transient voltage suppression (TVS) diode in SMC package, designed for primary-level surge protection of DC power rails and signal lines against IEC 61000-4-2 ESD (±30 kV air/contact) and IEC 61000-4-4 EFT (4 kV). It features a 28 V standoff voltage (VRM), 31.1–32.7 V breakdown at 1 mA, 45.4 V clamping voltage at 34 A (10/1000 µs), 1500 W peak pulse power, and 0.2 µA max leakage at 25 °C.
For engineers reviewing the SMCJ28A-TR datasheet, SMCJ28A-TR pinout, SMCJ28A-TR application, or SMCJ28A-TR equivalent, this device is selected for high-reliability industrial power supply input stages, automotive body control modules, PoE-powered equipment interfaces, and telecom line card protection where low-leakage, high-Tj (150 °C) operation and robust 8/20 µs surge handling (up to 10 kW) are required.
Technical Context
This unidirectional TVS diode operates as a voltage-clamped crowbar during transients: it remains high-impedance below VRM = 28 V, triggers at VBR = 31.1–32.7 V (1 mA), and limits surge energy with dynamic resistance RD = 0.325 Ω at 25 °C. Its planar junction enables stable performance up to Tj = 150 °C, sustaining 1250 W (10/1000 µs) at maximum junction temperature.
Compliance with IEC 61000-4-2 Level 4 (±30 kV), IEC 61000-4-4 Level 4 (4 kV), UL94 V0, and J-STD-020 MSL Level 1 confirms suitability for surface-mount reflow assembly and harsh EMC environments. The SMC package supports IPC7531 footprint and JEDEC registered outline with matte tin lead finish.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standoff Voltage (VRM) | 28 V - Maximum continuous reverse operating voltage before conduction begins. |
| Breakdown Voltage (VBR) | 31.1–32.7 V at 1 mA - Confirmed triggering threshold for reliable overvoltage detection. |
| Clamping Voltage (VCL) | 45.4 V at 34 A (10/1000 µs) - Peak voltage seen by protected circuit during worst-case surge. |
| Peak Pulse Power (PPP) | 1500 W (10/1000 µs) - Sustained surge energy handling capability under standard lightning waveform. |
| Leakage Current (IRM) | 0.2 µA at 25 °C - Minimal standby current draw critical for battery-backed or low-power systems. |
| Junction Temperature Range | −55 to +150 °C - Enables deployment in under-hood automotive, industrial motor drives, and outdoor telecom enclosures. |
| Dynamic Resistance (RD) | 0.325 Ω at 25 °C - Low impedance during clamping ensures rapid voltage stabilization and reduced stress on downstream components. |
Pinout & Package
The SMCJ28A-TR uses a 2-pin SMC (DO-214AB) surface-mount package with cathode band marking. Leads are matte tin-plated for solderability and RoHS compliance. Thermal resistance Rth(j-a) is 100 °C/W on recommended FR4 footprint (3.14 cm² copper per lead).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (unmarked end) | Current entry during forward surge (e.g., negative transients on grounded rail) | Connected to protected line; conducts only during reverse-biased overvoltage events. |
| Cathode (banded end) | Clamping reference node / surge return path | Typically tied to ground or common reference; defines polarity-sensitive clamping behavior. |
Key Features
| Feature | Design Value |
|---|---|
| High surge immunity | Withstands 10 kW (8/20 µs) surges - protects against severe lightning-induced transients in AC/DC front-ends. |
| Low leakage at elevated temperature | IR ≤ 0.2 µA at 25 °C and <1000 nA at 125 °C - preserves efficiency in high-temperature power conversion stages. |
| Stable clamping across temperature | VCL shift coefficient αT = 9.8 × 10−4/°C - ensures predictable protection margin from −55 to +150 °C. |
| Reflow-compatible packaging | MSL Level 1, JEDEC-compliant SMC outline, matte tin leads - supports automated high-volume PCB assembly without moisture sensitivity concerns. |
| IEC 61000-4-2/4-4 certified | Passes ±30 kV contact/air discharge and 4 kV EFT - eliminates need for external pre-compliance testing in industrial and automotive designs. |
Applications
| Industrial Power Supply Input | Automotive Body Control Module (BCM) |
|---|---|
|
Use Scenario: Protection of 24 V DC input stage against load dump, jump-start spikes, and ISO 7637-2 transients. IC Role / Device Role / Timing Role: Unidirectional TVS placed between VIN and chassis ground to clamp positive surges above 28 V. Use Value: Limits peak voltage to 45.4 V during 34 A transients, preventing damage to upstream DC-DC controllers and downstream microcontrollers. |
Use Scenario: Safeguarding LIN bus interface pins and sensor supply lines in door modules and lighting controls. IC Role / Device Role / Timing Role: Standoff-rated clamping element on 12 V supply rail and bidirectional data lines (with CA variant). Use Value: 0.2 µA leakage avoids battery drain; 150 °C rating ensures reliability in sealed, heat-trapped cabin environments. |
| Telecom Line Card Interface | PoE-Powered Equipment (PD) |
|
Use Scenario: Secondary surge protection on Ethernet PHY side of RJ45 connectors after primary gas discharge tube (GDT) stage. IC Role / Device Role / Timing Role: Fast-response clamping device absorbing residual energy from IEC 61000-4-4 4 kV bursts. Use Value: 45.4 V clamping prevents PHY IC latch-up; low capacitance (<100 pF at 10 V) avoids signal integrity degradation on 100BASE-TX lines. |
Use Scenario: Input rail protection for IEEE 802.3af/at PDs receiving power over twisted-pair cabling. IC Role / Device Role / Timing Role: Unidirectional TVS on PSE-side DC input to suppress induced surges from cable coupling and hot-plug events. Use Value: 1500 W rating handles worst-case PoE inrush + surge combinations; SMC package allows compact layout near connector. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ28A-TR | Lower PPP = 600 W (10/1000 µs); same VRM/VBR/VCL but higher RD = 0.55 Ω | Acceptable for lower-energy surges (e.g., consumer electronics), not for industrial 4 kV EFT or automotive load dump. | Select when cost or board space is constrained and surge threat level is ≤600 W. |
| 1.5KE28A | Through-hole DO-201 package; 1500 W rating but slower response (higher junction capacitance), no MSL Level 1 rating | Not suitable for automated SMT lines; thermal performance inferior due to larger thermal mass and no optimized footprint. | Choose only for legacy through-hole designs or prototyping where reflow compatibility is not required. |
Compared with SMBJ28A-TR and 1.5KE28A, SMCJ28A-TR delivers superior surge robustness (1500 W vs. 600 W), lower dynamic resistance (0.325 Ω vs. 0.55 Ω), and full SMT process support - making it optimal for high-reliability, high-volume industrial and automotive applications demanding consistent clamping and thermal stability.
Availability
SMCJ28A-TR is available at Aetrix Electronics and suitable for industrial power supply inputs, automotive body control modules, telecom line card interfaces, and PoE-powered equipment requiring stable component supply across extended temperature ranges and rigorous EMC standards.
Supply support for SMCJ28A-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, delivering innovative silicon solutions for automotive, industrial, and power management applications.
The SMCJ series belongs to ST's high-power TVS portfolio, engineered specifically for robust, low-leakage transient suppression in harsh electromagnetic environments - targeting design-in for mission-critical industrial and automotive subsystems.
FAQ
What is the maximum clamping voltage of SMCJ28A-TR under a 10/1000 µs surge?
The maximum clamping voltage (VCL) is 45.4 V at 34 A for a 10/1000 µs waveform, measured at Tamb = 25 °C. This value increases linearly with junction temperature at a coefficient of 9.8 × 10−4/°C, reaching approximately 48.2 V at Tj = 150 °C.
Can SMCJ28A-TR be used in bidirectional configurations?
No - SMCJ28A-TR is unidirectional and must be connected with cathode to ground (or reference) to protect against positive transients only. For bidirectional protection, ST offers the pin-compatible SMCJ28CA variant, which clamps both polarities symmetrically around 0 V.
What is the recommended PCB footprint for thermal reliability?
ST specifies a minimum copper area of 3.14 cm² (0.49 in²) under each lead on FR4 with 70 µm copper thickness. This achieves Rth(j-a) ≈ 100 °C/W and supports sustained 1250 W operation at Tj = 150 °C. The IPC7531-compliant footprint is detailed in Figure 14 of DS1284 Rev 11.
Does SMCJ28A-TR meet automotive AEC-Q200 requirements?
No - while rated for −55 to +150 °C operation and compliant with IEC 61000-4-2/4-4, SMCJ28A-TR is not AEC-Q200 qualified. For automotive-grade TVS diodes, ST recommends the SMAJ28A-Q or SMF28A-Q series, which undergo full stress testing per AEC-Q200 Rev D.
SMCJ28A-TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AB, SMC
- Series:
- SMCJ, 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:
- 59V
- Current - Peak Pulse (10/1000µs):
- 169A (8/20µs)
- Power - Peak Pulse:
- 1500W (1.5kW)
- 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:
- SMC (DO-214AB)
SMCJ28A-TR FAQ
1.How can I place an order for SMCJ28A-TR through Aetrix?
Please submit a Request for Quotation (RFQ) for SMCJ28A-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 SMCJ28A-TR reliable?
The price and inventory of SMCJ28A-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMCJ28A-TR is usually 5 days.
3.What payment methods are accepted for SMCJ28A-TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMCJ28A-TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMCJ28A-TR?
SMCJ28A-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMCJ28A-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 SMCJ28A-TR?
For technical support, including SMCJ28A-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMCJ28A-TR requirements.
6.How does Aetrix verify that SMCJ28A-TR is sourced from the original manufacturer or authorized distributors?
All SMCJ28A-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 SMCJ28A-TR meets industry standards.
7.What is the process for return or replacement of SMCJ28A-TR?
All SMCJ28A-TR units undergo pre-shipment inspection (PSI). If there is an issue with SMCJ28A-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 SMCJ28A-TR part is unused and in its original packaging.
Return procedure for SMCJ28A-TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMCJ28A-TR Tags
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