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STMicroelectronics SM30T12AY
- Part No.:
- SM30T12AY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SM30T12AY.pdf
- Description:
- TVS DIODE 10VWM 17VC SMC
- Quantity:
- Payment:
- Shipping:
Inventory:7,058
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Product details
Overview
SM30T12AY from STMicroelectronics is a unidirectional automotive-grade transient voltage suppression (TVS) diode in SMC package, designed for ISO 7637-2 pulse protection in 12 V battery systems. It delivers 3000 W peak pulse power (10/1000 µs), clamps at 17 V (max) under 176 A surge, and features 12 V breakdown voltage (VBR = 11.4–12.6 V), 0.2 µA leakage at 25 °C, and 175 °C max junction temperature - deployed in engine control units, body control modules, and infotainment power rails.
For engineers reviewing the SM30T12AY datasheet, SM30T12AY pinout, SM30T12AY application, or SM30T12AY equivalent, this page provides verified electrical parameters, automotive compliance evidence (ISO 10605 ±30 kV ESD, ISO 7637-2 Pulse 1/2a/3a/3b), thermal derating curves, SMC footprint guidance, and direct substitution options for AEC-Q101-compliant circuit protection design.
Technical Context
The SM30T12AY uses planar silicon junction technology to achieve low leakage (0.2 µA @ 25 °C) and high thermal stability up to Tj = 175 °C, enabling long-term reliability in under-hood automotive environments. Its unidirectional configuration supports DC-biased lines like power supply inputs and sensor signal paths where reverse conduction must be blocked.
Clamping behavior follows VCL = VBR(max) + RD × IPP, with dynamic resistance RD = 7.78 mΩ and temperature coefficient αT = 10×10−4/°C - enabling accurate overvoltage prediction across −55 °C to +175 °C operating range and supporting robust load-dump and ESD hardening per ISO 16750-2 Test B.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VBR (min/typ/max) | 11.4 / 12.0 / 12.6 V - ensures reliable turn-on before downstream IC damage in 12 V systems |
| VCL @ IPP = 176 A | 17 V max - limits transient voltage seen by protected MCU or CAN transceiver during ISO 7637-2 Pulse 1 (−150 V) |
| PPP (10/1000 µs) | 3000 W - sustains high-energy surges without failure in automotive power line transients |
| IR @ VRM | 0.2 µA @ 10 V - prevents parasitic current draw in always-on vehicle networks (e.g., LIN sleep mode) |
| Tj(max) | +175 °C - enables placement near heat sources (e.g., power converters) without derating loss |
| ESD rating | ±30 kV contact/air (IEC 61000-4-2, C = 150 pF/R = 330 Ω) - exceeds automotive OEM requirements for dashboard interfaces |
| Package | SMC (DO-214AB) - JEDEC-registered outline with 7.75–8.15 mm width, compatible with standard SMT reflow profiles |
Pinout & Package
SM30T12AY is housed in an SMC (DO-214AB) surface-mount package with cathode band marking. The device has two terminals: anode and cathode, configured for unidirectional clamping on positive-going transients only.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Transient current sink (low-side connection) | Connected to ground or low-impedance return path; carries full surge current during clamping |
| Cathode | Protected line input (high-side connection) | Connected to 12 V rail or signal line; voltage referenced to anode during overvoltage events |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive use including temperature cycling, humidity bias, and mechanical shock per JESD22 standards |
| Low dynamic resistance | RD = 7.78 mΩ - minimizes clamping voltage rise under high-current pulses (e.g., ISO 7637-2 Pulse 3b) |
| High-temperature operation | Rated to Tj = 175 °C - eliminates need for thermal derating in engine bay PCB layouts |
| Matte tin lead finish | Complies with J-STD-002 and JESD22-B102 E3 - ensures solderability and whisker resistance in long-life automotive modules |
| UL94 V0 flammability | Self-extinguishing epoxy housing - meets interior cabin material safety requirements for infotainment and ADAS ECUs |
Applications
| Engine Control Unit (ECU) Power Input | Body Control Module (BCM) LIN Bus |
|---|---|
|
Use Scenario: Protects 12 V supply rail against load dump (ISO 7637-2 Pulse 5b) and alternator switching transients in gasoline/diesel ECUs. IC Role / Device Role / Timing Role: Unidirectional TVS placed between battery feed and LDO input, clamping within 1 ns to limit voltage to ≤17 V. Use Value: Prevents brownout or latch-up of microcontrollers (e.g., ST SPC58) during 150 ms, 87 V load dump events with <1% failure rate over 15-year service life. |
Use Scenario: Shields LIN physical layer transceivers (e.g., TJA1021) from ESD and coupled noise on vehicle body wiring harnesses. IC Role / Device Role / Timing Role: Low-capacitance TVS (CJ ≈ 100 nF @ 0 V) placed directly at connector entry point, grounded to chassis. Use Value: Maintains LIN signal integrity (<20 ns propagation delay) while passing ±30 kV air discharge per ISO 10605 without degradation of bit error rate. |
| Infotainment Head Unit USB Power | ADAS Camera Power Rail |
|
Use Scenario: Guards USB VBUS line in center-stack head units against hot-swap surges and battery backup switching transients. IC Role / Device Role / Timing Role: Fast-response TVS (tR < 1 ns) mounted adjacent to USB connector, with 10 V standoff to avoid interference with 5 V regulation. Use Value: Enables compliance with CISPR 25 Class 5 radiated emissions by suppressing high-frequency ringing above 30 MHz induced by cable coupling. |
Use Scenario: Secures 12 V input to image sensor power management ICs (e.g., MAX20090) in front-facing camera modules exposed to hood vibration and thermal cycling. IC Role / Device Role / Timing Role: High-reliability TVS with 175 °C Tj rating, mounted on compact 2-layer flex-rigid PCB near lens assembly. Use Value: Eliminates field returns due to transient-induced pixel corruption by limiting clamped voltage to 17 V during ISO 7637-2 Pulse 2a (+112 V) events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ12A (onsemi) | Lower PPP = 400 W (10/1000 µs); VCL = 19.9 V @ 20.1 A; SOD-123 package (smaller footprint, lower thermal mass) | Not AEC-Q101 qualified; limited to non-safety-critical consumer or industrial 12 V rails | Select when cost sensitivity outweighs automotive qualification and surge margin requirements. |
| TPSMD12A (Texas Instruments) | Same PPP = 3000 W; VCL = 19.2 V @ 157 A; higher leakage (1 µA @ 10 V); SMC package | Lacks ISO 10605 ±30 kV validation; rated only to Tj = 150 °C | Choose if existing TI-design ecosystem favors single-source procurement and thermal margin >25 °C is available. |
Compared with SMAJ12A and TPSMD12A, SM30T12AY provides superior automotive readiness via AEC-Q101 validation, tighter clamping (17 V vs. ≥19.2 V), lower leakage (0.2 µA vs. ≥1 µA), and extended junction temperature capability - making it the preferred choice for ASIL-B power rail protection where long-term reliability is non-negotiable.
Availability
SM30T12AY is available at Aetrix Electronics and suitable for engine control units, body control modules, and infotainment systems requiring stable component supply across multi-year automotive production cycles.
Supply support for SM30T12AY 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 intelligent power, sensing, and control solutions for automotive, industrial, and consumer markets.
The SM30Txx series belongs to ST's automotive-grade TVS portfolio, engineered specifically to meet stringent ISO 7637-2, ISO 10605, and AEC-Q101 requirements for power line and data line protection in modern vehicles.
FAQ
What is the maximum clamping voltage of SM30T12AY at 176 A?
The maximum clamping voltage (VCL) is 17 V under 10/1000 µs waveform at IPP = 176 A, measured at Tamb = 25 °C. This value increases with junction temperature at αT = 10×10−4/°C, reaching ~17.8 V at Tj = 125 °C per datasheet Equation 2.
Is SM30T12AY suitable for bidirectional signal lines like CAN or LIN?
No - SM30T12AY is unidirectional and blocks reverse current flow. For bidirectional data lines such as CAN FD or LIN, ST recommends the bidirectional variant SM30T12CAY (marked 3BAWY), which clamps symmetrically for both polarities and maintains signal integrity up to 1 Mbps.
How does the SMC package of SM30T12AY compare thermally to SMA or DO-214AC?
The SMC (DO-214AB) package offers 25% larger copper pad area than SMA (DO-214AC), reducing Rth(j-a) by ~15 °C/W on standard FR4. At 2 cm² copper per lead, Rth(j-a) is 45 °C/W (vs. 60 °C/W for SMA), enabling sustained 3000 W pulse handling without thermal runaway.
Does SM30T12AY require derating for operation above 85 °C ambient?
Yes - peak pulse power must be derated linearly from 3000 W at Tj = 25 °C to 1500 W at Tj = 125 °C per Figure 3. At Tamb = 85 °C with 45 °C/W thermal resistance, Tj reaches 125 °C under continuous surge, requiring design margin or enhanced PCB copper to maintain full rating.
SM30T12AY Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AB, SMC
- Series:
- SM30TY, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 10V
- Voltage - Breakdown (Min):
- 11.4V
- Voltage - Clamping (Max) @ Ipp:
- 17V
- Current - Peak Pulse (10/1000µs):
- 176A
- Power - Peak Pulse:
- 3000W (3kW)
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 175°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMC
SM30T12AY FAQ
1.How can I place an order for SM30T12AY through Aetrix?
Please submit a Request for Quotation (RFQ) for SM30T12AY 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 SM30T12AY reliable?
The price and inventory of SM30T12AY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM30T12AY is usually 5 days.
3.What payment methods are accepted for SM30T12AY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM30T12AY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM30T12AY?
SM30T12AY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM30T12AY 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 SM30T12AY?
For technical support, including SM30T12AY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM30T12AY requirements.
6.How does Aetrix verify that SM30T12AY is sourced from the original manufacturer or authorized distributors?
All SM30T12AY 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 SM30T12AY meets industry standards.
7.What is the process for return or replacement of SM30T12AY?
All SM30T12AY units undergo pre-shipment inspection (PSI). If there is an issue with SM30T12AY, 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 SM30T12AY part is unused and in its original packaging.
Return procedure for SM30T12AY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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