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STMicroelectronics SM15T12A
- Part No.:
- SM15T12A
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SM15T12A.pdf
- Description:
- TVS DIODE 10.2VWM 21.7VC SMC
- Quantity:
- Payment:
- Shipping:
Inventory:8,378
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Product details
Overview
SM15T12A from STMicroelectronics is a unidirectional 1500 W transient voltage suppression (TVS) diode in SMC package, designed for IEC 61000-4-2 ESD protection (30 kV air/contact) and IEC 61000-4-4 surge immunity (4 kV level 4). It features 12 V breakdown voltage (VBR = 10.2–12.6 V), 16.7 V clamping voltage at 1 A (VCL), and 0.2 µA leakage at 25 °C. Used in DC power rails of industrial PLCs, telecom interfaces, and SMPS input stages where low leakage and high Tj (150 °C) ensure long-term reliability.
For engineers reviewing the SM15T12A datasheet, SM15T12A pinout, SM15T12A application, or SM15T12A equivalent, key selection criteria include clamping voltage under 10/1000 µs surge, junction temperature derating above 25 °C, dynamic resistance (RD = 0.046 Ω), and compatibility with IPC7531-compliant SMC footprints.
Technical Context
The SM15T12A employs planar silicon avalanche technology to deliver precise, repeatable clamping during fast transients. Its unidirectional configuration supports DC-biased lines, with VBR specified at 1 mA and temperature coefficient αT = 7.8 × 10−4/°C enabling accurate VBR calculation across −55 °C to +150 °C.
Clamping behavior follows VCL(Tj) = VCL(25 °C) × [1 + αT(Tj − 25)], and peak pulse power drops linearly from 1500 W at Tj = 25 °C to 1250 W at Tj = 150 °C per 10/1000 µs waveform. Dynamic resistance RD = 0.046 Ω governs voltage rise under surge current beyond rated IPP.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VBR (min/typ/max) | 10.2 / 11.4 / 12.0 V at IBR = 1 mA - defines minimum voltage at which avalanche conduction begins; critical for ensuring protection triggers before downstream IC damage. |
| VCL @ IPP = 1 A | 16.7 V - maximum voltage seen by protected circuit during 1 A 10/1000 µs surge; determines safe margin below IC absolute max ratings. |
| IPP (10/1000 µs) | 90 A - peak surge current capability at 1500 W; sets maximum line surge energy the device can absorb without failure. |
| RD | 0.046 Ω - dynamic resistance governing VCL rise above rated IPP; lower RD improves clamping tightness under higher surges. |
| IR @ VRM | 0.2 µA at 25 °C - ultra-low reverse leakage ensures minimal power loss and signal integrity on high-impedance or battery-backed lines. |
| Tj max | +150 °C - enables operation in thermally constrained environments (e.g., enclosed power supplies) without derating penalty up to full rating. |
| ESD Rating | ±30 kV contact & air discharge per IEC 61000-4-2 - exceeds Level 4, eliminating need for secondary ESD stages in most industrial interfaces. |
Pinout & Package
SM15T12A is housed in an SMC (DO-214AB) surface-mount package with two terminals: Cathode (marked side) and Anode. The package complies with JEDEC MO-136AC and IPC7531 footprint standards, 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 avalanche current to ground during overvoltage events; polarity must match DC bias direction. |
| Anode | Reference node | Typically tied to system ground or lowest potential rail; establishes reference for clamping action and defines unidirectional conduction path. |
Key Features
| Feature | Design Value |
|---|---|
| 1500 W peak pulse power (10/1000 µs) | Enables single-device protection against severe lightning-induced surges in industrial 24 V DC systems without parallel staging. |
| 0.2 µA max leakage at 25 °C | Preserves battery life and avoids false triggering in low-power sensor nodes and always-on monitoring circuits. |
| 150 °C operating junction temperature | Supports placement near heat-generating components (e.g., MOSFETs, inductors) without thermal derating in compact SMPS designs. |
| IEC 61000-4-2 ±30 kV ESD robustness | Eliminates need for external ESD suppressors on front-panel connectors and human-accessible ports in medical and test equipment. |
| Dynamic resistance RD = 0.046 Ω | Ensures predictable clamping voltage rise (ΔV = RD × ΔI) under variable surge currents, simplifying worst-case margin analysis. |
Applications
| Industrial PLC I/O Modules | Telecom Line Interface Cards |
|---|---|
|
Use Scenario: 24 V DC digital input channels exposed to field wiring transients and ESD from operator interaction. IC Role / Device Role: Primary surge clamp on signal line between connector and optocoupler input stage. Use Value: Limits transient voltage to ≤16.7 V, protecting 5 V logic-level optocouplers and preventing latch-up or gate oxide damage. |
Use Scenario: Protection of RS-485 transceiver pins connected to outdoor cabling in base station backhaul links. IC Role / Device Role: Unidirectional TVS placed between transceiver VCC-referenced data lines and chassis ground. Use Value: Absorbs 4 kV IEC 61000-4-4 surges while maintaining <0.2 µA leakage to avoid bias current errors in precision differential receivers. |
| AC-DC SMPS Input Stage | Automotive Body Control Module (BCM) Power Rails |
|
Use Scenario: Secondary-side 12 V output rail of offline flyback converter subject to load-dump and hot-swap transients. IC Role / Device Role: Clamp device across regulated 12 V bus, referenced to common ground plane. Use Value: Withstands 1250 W surge at 150 °C junction temperature, enabling reliable operation without heatsinking in sealed enclosures. |
Use Scenario: 12 V supply rail feeding microcontroller and CAN transceivers in interior lighting control units. IC Role / Device Role: Unidirectional TVS on main power feed, positioned upstream of LDO regulators. Use Value: Provides ±30 kV ESD immunity per IEC 61000-4-2 while adding only 0.2 µA standby current-critical for low-quiescent-current BCM designs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ12A (Bourns) | Same SMC package, but 600 W rating (vs. 1500 W); VCL = 19.9 V @ 32.4 A; RD = 0.12 Ω. | Limited to lower-energy surges; less suitable for 4 kV IEC 61000-4-4 applications requiring >1 kA peak current handling. | Select when cost sensitivity outweighs surge margin, and system testing confirms 600 W suffices. |
| 1.5KE12A (ON Semiconductor) | Through-hole DO-201 package; 1500 W rating; VCL = 18.2 V @ 82.4 A; RD = 0.075 Ω; no MSL rating. | Requires PCB real estate for axial leads; incompatible with automated SMT assembly; unsuitable for high-density layouts. | Choose only for legacy through-hole designs or prototyping where reflow compatibility is not required. |
Compared with SMBJ12A and 1.5KE12A, SM15T12A delivers superior clamping performance (16.7 V vs. ≥18.2 V), lower dynamic resistance (0.046 Ω vs. ≥0.075 Ω), and SMT-ready SMC packaging with MSL Level 1 and IPC7531 compliance-making it optimal for high-reliability, high-density industrial power and interface protection.
Availability
SM15T12A is available at Aetrix Electronics and suitable for industrial PLC I/O modules, telecom line interface cards, and AC-DC SMPS input stages requiring stable component supply, consistent parametric performance, and full traceability across production batches.
Supply support for SM15T12A 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, MCU, power, and sensing solutions for industrial, automotive, and consumer markets.
The SM15T series belongs to ST's high-power TVS portfolio, engineered specifically for robust, low-leakage transient protection in space-constrained, thermally demanding applications such as industrial automation and telecom infrastructure.
FAQ
What is the maximum clamping voltage of SM15T12A under a 10/1000 µs surge?
The maximum clamping voltage is 16.7 V at 1 A peak pulse current (IPP = 1 A) for a 10/1000 µs waveform, measured at Tj = 25 °C. This value increases with junction temperature per the coefficient αT = 7.8 × 10−4/°C, reaching ~17.3 V at Tj = 125 °C.
Can SM15T12A be used in bidirectional signal lines?
No-SM15T12A is unidirectional and must be installed with cathode toward the protected line and anode to ground. For bidirectional protection (e.g., RS-485), use SM15T12CA, which has symmetrical breakdown in both polarities and identical clamping performance in either direction.
What is the recommended PCB footprint for SM15T12A?
The recommended footprint follows IPC7531 and JEDEC MO-136AC standards: pad length 5.11 mm, pad width 1.54 mm, center-to-center spacing 8.19 mm, and copper area per pad ≥3.14 cm² to maintain Rth(j-a) ≤ 4.5 °C/W and support full 1500 W surge capability.
Does SM15T12A require derating at elevated ambient temperatures?
Yes-peak pulse power must be derated linearly from 1500 W at Tj = 25 °C to 1250 W at Tj = 150 °C. Since Tj = Tamb + Pdiss × Rth(j-a), ambient temperature limits depend on PCB copper area; for standard FR4 with 70 µm Cu, Tamb should not exceed 85 °C to sustain full rating.
SM15T12A 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):
- 10.2V
- Voltage - Breakdown (Min):
- 11.4V
- Voltage - Clamping (Max) @ Ipp:
- 21.7V
- Current - Peak Pulse (10/1000µs):
- 461A (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
SM15T12A FAQ
1.How can I place an order for SM15T12A through Aetrix?
Please submit a Request for Quotation (RFQ) for SM15T12A 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 SM15T12A reliable?
The price and inventory of SM15T12A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM15T12A is usually 5 days.
3.What payment methods are accepted for SM15T12A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM15T12A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM15T12A?
SM15T12A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM15T12A 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 SM15T12A?
For technical support, including SM15T12A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM15T12A requirements.
6.How does Aetrix verify that SM15T12A is sourced from the original manufacturer or authorized distributors?
All SM15T12A 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 SM15T12A meets industry standards.
7.What is the process for return or replacement of SM15T12A?
All SM15T12A units undergo pre-shipment inspection (PSI). If there is an issue with SM15T12A, 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 SM15T12A part is unused and in its original packaging.
Return procedure for SM15T12A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SM15T12A Tags
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