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STMicroelectronics SM15T15A
- Part No.:
- SM15T15A
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SM15T15A.pdf
- Description:
- TVS DIODE 12.8VWM 27.2VC SMC
- Quantity:
- Payment:
- Shipping:
Inventory:7,007
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Product details
Overview
SM15T15A from STMicroelectronics is a unidirectional 1500 W transient voltage suppression diode in SMC package, designed for IEC 61000-4-2 ESD (30 kV air/contact) and IEC 61000-4-4 surge (4 kV level 4) protection. It features 15 V standoff voltage (VRWM), 21.2 V clamping voltage at 1 A (VCL), 0.2 µA leakage at 25 °C, and operates up to 150 °C junction temperature - deployed in industrial power supplies and telecom interface circuits.
For engineers reviewing the SM15T15A datasheet, SM15T15A pinout, SM15T15A application, or SM15T15A equivalent, key selection criteria include clamping voltage under 10/1000 µs surge, low leakage for high-impedance signal lines, thermal derating above 25 °C, and SMC footprint compatibility with IPC7531 standards.
Technical Context
The SM15T15A uses planar silicon avalanche technology to achieve precise breakdown at 15 V (VBR min = 12.8 V, typ = 14.3 V), with dynamic resistance of 0.076 Ω enabling fast response to transients. Its unidirectional configuration provides forward conduction path only during reverse overvoltage events, supporting DC-biased protection schemes.
Thermal performance is defined by junction-to-ambient thermal resistance (Rth(j-a)) of ~100 °C/W on standard FR4 PCB with recommended copper area, and peak pulse power drops linearly from 1500 W at 25 °C to 1250 W at 150 °C per Figure 3 - critical for sustained surge duty in enclosed industrial enclosures.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 15 V - maximum continuous reverse working voltage before clamping begins |
| VBR (min/typ) | 12.8 V / 14.3 V at 1 mA - ensures reliable triggering margin below system rail voltage |
| VCL @ 1 A | 21.2 V - clamping voltage limits protected circuit stress during 10/1000 µs surges |
| IPP (10/1000 µs) | 71 A - peak surge current capability at rated clamping voltage |
| IR @ VRWM | 0.2 µA at 25 °C - ultra-low leakage preserves signal integrity in high-Z analog/sensor inputs |
| Tj max | +150 °C - enables operation in thermally constrained environments like sealed power converters |
| Package | SMC (DO-214AB) - JEDEC-registered surface-mount outline with 7.75–8.15 mm body width |
Pinout & Package
SM15T15A is housed in an SMC (DO-214AB) plastic package with two terminals: cathode (marked end) and anode. The package complies with IPC7531 footprint and JEDEC MO-136AC outline, featuring matte tin-plated leads and MSL level 1 moisture sensitivity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (marked end) | Surge current sink | Connected to protected line; conducts during reverse overvoltage to shunt energy to ground |
| Anode | Reference node | Typically tied to system ground or lower-potential rail; completes clamping path |
Key Features
| Feature | Design Value |
|---|---|
| IEC 61000-4-2 ESD robustness | 30 kV contact/air discharge - exceeds level 4, eliminating need for external spark gaps in front-end interfaces |
| Low dynamic resistance | 0.076 Ω - minimizes voltage overshoot during fast-rising transients (e.g., relay bounce, inductive switching) |
| High-temperature stability | Rated for full 1500 W pulse power at Tj = 25 °C, derated to 1250 W at Tj = 150 °C - supports compact thermal design |
| UL 497B certification | QVGQ2.E136224 - validates suitability for telecom/data line surge protection per UL safety standards |
| Planar junction construction | Enables tight VBR tolerance (±5%) and stable leakage across temperature - critical for precision sensor front-ends |
Applications
| Industrial Power Supply Input | RS-485 Data Line Protection |
|---|---|
Use Scenario: 24 V DC input stage of programmable logic controller (PLC) exposed to load dump and inductive kickback. IC Role / Device Role / Timing Role: Unidirectional TVS diode placed between +24 V rail and chassis ground to clamp surges before they reach DC-DC converter input. Use Value: 21.2 V clamping at 71 A prevents MOSFET gate oxide damage and maintains <100 ns response time under 10/1000 µs transients. | Use Scenario: Differential pair of RS-485 transceiver connected to long outdoor cable runs subject to lightning-induced surges. IC Role / Device Role / Timing Role: One SM15T15A per line (A and B) referenced to local ground, providing common-mode surge suppression. Use Value: 0.2 µA leakage avoids bias current error in high-impedance termination networks; 15 V VRWM accommodates ±12 V bus swing without false triggering. |
| Telecom DSL Line Interface | Automotive Body Control Module (BCM) Sensor Inputs |
Use Scenario: Analog front-end of DSL line card handling POTS/ADSL signals with AC coupling and DC bias. IC Role / Device Role / Timing Role: Unidirectional TVS placed across transformer secondary to protect PHY IC from induced surges on twisted-pair lines. Use Value: 30 kV ESD rating meets GR-1089-CORE requirements; planar junction ensures no parameter drift after repeated 8/20 µs surge exposure. | Use Scenario: 5 V analog sensor input (e.g., temperature, pressure) in BCM exposed to ISO 7637-2 pulse 1/2a/5a transients. IC Role / Device Role / Timing Role: TVS mounted directly at connector entry point to clamp fast transients before reaching op-amp input stage. Use Value: 150 °C operating junction temperature allows placement near heat-generating MCU; low capacitance (<100 pF at 0 V) preserves signal bandwidth up to 10 MHz. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ15A (Bourns) | Same SMC package, 15 V VRWM, but higher VCL = 24.4 V at 1 A and 1000 W peak power | Limited to lower-energy surges; less margin for 24 V systems with tight downstream voltage tolerances | Prefer when cost sensitivity outweighs clamping voltage performance |
| P6SMB15A (Littelfuse) | Identical electrical specs (VRWM = 15 V, VCL = 21.2 V, 1500 W), but higher leakage (1 µA) and no UL 497B listing | Not certified for telecom line-side use; requires additional safety review for UL-compliant designs | Select only for non-certified industrial control where leakage is not critical |
Compared with SMBJ15A and P6SMB15A, SM15T15A delivers superior clamping performance at full rated power, lower leakage for precision analog paths, and UL 497B certification - making it optimal for safety-critical telecom and industrial interfaces requiring validated surge immunity.
Availability
SM15T15A is available at Aetrix Electronics and suitable for industrial power supply inputs, RS-485 data line protection, telecom DSL line interfaces, and automotive BCM sensor inputs requiring stable component supply across extended temperature and surge conditions.
Supply support for SM15T15A 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 automotive, industrial, and power discrete solutions with emphasis on reliability and environmental compliance.
The SM15T series belongs to ST's high-power TVS portfolio, engineered specifically for robust IEC 61000-4-2/4-4/4-5 surge protection in space-constrained industrial and telecom equipment.
FAQ
What is the maximum clamping voltage of SM15T15A under a 10/1000 µs surge?
The maximum clamping voltage (VCL) of SM15T15A is 21.2 V at 1 A for a 10/1000 µs waveform, measured at Tj = 25 °C. This value increases with junction temperature per the αT coefficient (8.4 × 10−4/°C), reaching approximately 22.5 V at 125 °C.
Is SM15T15A suitable for bidirectional signal lines like USB or CAN?
No - SM15T15A is unidirectional and intended for DC-biased lines such as power rails or single-ended data lines. For bidirectional applications like USB or CAN, the SM15T15CA variant must be used, which provides symmetrical clamping in both polarities.
Does SM15T15A require derating when mounted on a 1 oz copper PCB?
Yes - thermal performance depends on copper area. With the recommended footprint (Figure 14), Rth(j-a) is ~100 °C/W. On a standard 1 oz (35 µm) FR4 board without extended copper pours, derating to ≤1000 W peak power is advised for continuous surge duty above 70 °C ambient.
What marking code identifies SM15T15A on the device body?
SM15T15A is marked as "MDX" on the cathode end of the SMC package, per Table 6 in DS0683 Rev 8. This 3-character code distinguishes it from other variants in the SM15TxxA family and confirms unidirectional configuration.
SM15T15A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AB, SMC
- Series:
- SM15T, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 12.8V
- Voltage - Breakdown (Min):
- 14.3V
- Voltage - Clamping (Max) @ Ipp:
- 27.2V
- Current - Peak Pulse (10/1000µs):
- 368A (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
SM15T15A FAQ
1.How can I place an order for SM15T15A through Aetrix?
Please submit a Request for Quotation (RFQ) for SM15T15A 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 SM15T15A reliable?
The price and inventory of SM15T15A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM15T15A is usually 5 days.
3.What payment methods are accepted for SM15T15A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM15T15A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM15T15A?
SM15T15A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM15T15A 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 SM15T15A?
For technical support, including SM15T15A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM15T15A requirements.
6.How does Aetrix verify that SM15T15A is sourced from the original manufacturer or authorized distributors?
All SM15T15A 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 SM15T15A meets industry standards.
7.What is the process for return or replacement of SM15T15A?
All SM15T15A units undergo pre-shipment inspection (PSI). If there is an issue with SM15T15A, 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 SM15T15A part is unused and in its original packaging.
Return procedure for SM15T15A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SM15T15A Tags
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