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STMicroelectronics SM50T19AY
- Part No.:
- SM50T19AY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SM50T19AY.pdf
- Description:
- AUTOMOTIVE 5000 W, 16 V TVS IN S
- Quantity:
- Payment:
- Shipping:
Inventory:2,489
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Product details
Overview
SM50T19AY from STMicroelectronics is an AEC-Q101-qualified unidirectional transient voltage suppression (TVS) diode in SMC package, designed for automotive power line protection. It features a 19 V breakdown voltage (VBR = 17.9–19.8 V), 26 V clamping voltage at 192 A (8/20 µs), 5000 W peak pulse power (10/1000 µs), and ultra-low leakage current of 0.2 µA at 25 °C - enabling robust surge immunity in 12 V battery systems including e-breaker circuits compliant with ISO 7637-2 Pulse 1/2a/3a/3b and ISO 16750.
For engineers reviewing the SM50T19AY datasheet, SM50T19AY pinout, SM50T19AY application, or SM50T19AY equivalent, this device is selected for high-reliability automotive ESD and load-dump protection where junction temperature up to +175 °C, low dynamic resistance (13.8 mΩ), and JEDEC-registered SMC footprint compatibility are critical design requirements.
Technical Context
The SM50T19AY employs planar silicon avalanche technology to achieve stable VBR temperature coefficient (αT = 10 × 10−4/°C) and low leakage across −55 °C to +175 °C operating junction range. Its unidirectional configuration provides forward conduction path during negative transients while blocking reverse current until VBR is exceeded.
Clamping performance is defined by dynamic resistance (RD = 13.8 mΩ) and VCL = 26 V @ IPP = 192 A (8/20 µs), ensuring predictable voltage limiting under ISO 7637-2 Pulse 1 (−150 V), Pulse 2a (+112 V), Pulse 3a (−220 V), and Pulse 3b (+150 V). Thermal impedance is optimized for FR4 PCBs with recommended 3.14 cm² copper area per lead.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VBR (min/typ/max) | 17.9 / 18.8 / 19.8 V - ensures reliable turn-on before system damage at nominal 19 V rating |
| VCL @ 192 A (8/20 µs) | 26 V - limits downstream voltage to safe level during 192 A surge events |
| IPP (8/20 µs) | 192 A - supports high-energy transient absorption without failure |
| RD | 13.8 mΩ - minimizes clamping voltage rise under high-current pulses |
| IR @ VRM = 16 V | 0.2 µA at 25 °C - prevents standby power loss and signal interference in always-on modules |
| Tj max | +175 °C - enables placement near hot engine-control units without derating |
| Package | SMC (DO-214AB) - JEDEC-registered, IPC7531-compliant footprint for automated assembly |
Pinout & Package
SM50T19AY uses the standard SMC (DO-214AB) surface-mount package with cathode-bar marking. The device has two terminals: anode and cathode, configured for unidirectional operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Input terminal for negative transients | Connected to protected line (e.g., battery rail); conducts during reverse-biased surges |
| Cathode | Output/reference terminal | Connected to ground or low-impedance return path; defines polarity and clamping reference |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive under-hood environments including thermal cycling, humidity, and mechanical shock |
| ISO 10605 ESD immunity | 30 kV contact/air discharge - exceeds automotive ESD requirements without external shielding |
| IEC 61000-4-2 Level 4 compliance | 30 kV air/contact discharge - ensures robustness against human-body-model ESD in infotainment and ADAS interfaces |
| Low dynamic resistance | 13.8 mΩ - reduces VCL overshoot during fast-rising transients (e.g., ISO 7637-2 Pulse 3b) |
| Planar junction construction | Enables stable leakage (<0.2 µA) and predictable VBR drift up to +175 °C junction temperature |
Applications
| Engine Control Unit (ECU) Power Input | Body Control Module (BCM) LIN Bus Line |
|---|---|
|
Use Scenario: Protection of 12 V supply rail against load dump (ISO 7637-2 Pulse 5b) and alternator-induced spikes. IC Role / Device Role / Timing Role: Unidirectional TVS clamp placed between battery input and DC-DC converter input stage. Use Value: Limits transient voltage to ≤26 V during 192 A surges, preventing overvoltage shutdown or MOSFET gate oxide damage in upstream regulators. |
Use Scenario: ESD and coupled noise suppression on LIN physical layer lines exposed to cabin harnesses. IC Role / Device Role / Timing Role: Low-capacitance TVS connected between LIN bus and chassis ground, referenced to local ground plane. Use Value: Clamps 30 kV ESD events within nanoseconds while adding <1 pF parasitic capacitance, preserving LIN signal integrity at 19.2 kbps. |
| e-Brake Actuator Power Stage | ADAS Camera Power Supply |
|
Use Scenario: Surge protection for high-side switch drivers in electric parking brake control modules. IC Role / Device Role / Timing Role: TVS placed directly at motor driver IC power pins to absorb inductive kickback from solenoid coils. Use Value: Withstands repeated 5000 W (10/1000 µs) pulses and maintains <0.2 µA leakage at 125 °C ambient, ensuring long-term reliability in sealed actuators. |
Use Scenario: Input rail protection for image sensor power supplies in rear-view and surround-view cameras. IC Role / Device Role / Timing Role: Unidirectional TVS on 5 V or 3.3 V camera rail, coordinated with ceramic decoupling capacitors. Use Value: Prevents latch-up or pixel corruption during hot-plug events and ISO 7637-2 Pulse 3a (−220 V) transients on vehicle harnesses. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ19A | VBR = 21.1–23.3 V; VCL = 30.6 V @ 152 A; RD ≈ 20 mΩ; SMC package | Higher clamping voltage and lower IPP (152 A vs. 192 A) reduces margin for ISO 7637-2 Pulse 1 (−150 V) | Acceptable for non-critical 12 V loads but not recommended for e-brake or ECU primary rail where 26 V clamping is specified. |
| SMBJ19A | VBR = 21.1–23.3 V; VCL = 30.6 V @ 152 A; SMB package (smaller footprint, higher thermal resistance) | SMB package increases junction-to-ambient thermal resistance by ~25 °C/W vs. SMC, limiting sustained surge capability | Only suitable for space-constrained designs with lower duty-cycle transients; requires larger copper pour to match SM50T19AY thermal performance. |
Compared with SMAJ19A and SMBJ19A, SM50T19AY delivers lower clamping voltage (26 V vs. 30.6 V), higher surge current rating (192 A vs. 152 A), and superior thermal management in SMC package - making it the preferred choice for AEC-Q101-compliant automotive power rails demanding strict voltage limiting and long-term reliability at +175 °C.
Availability
SM50T19AY is available at Aetrix Electronics and suitable for engine control units, body control modules, e-brake actuators, and ADAS camera power supplies requiring stable component supply across automotive production lifecycles.
Supply support for SM50T19AY 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, specializing in automotive, industrial, and power management solutions.
SM50T19AY belongs to the SM50TY series of AEC-Q101-qualified TVS diodes engineered specifically for automotive power-line surge protection - targeting compliance with ISO 7637-2, ISO 16750, and ISO 10605 in harsh under-hood and cabin environments.
FAQ
What is the maximum clamping voltage of SM50T19AY under an 8/20 µs surge?
The SM50T19AY clamps to 26 V when subjected to a 192 A peak current pulse with 8/20 µs waveform, as specified in Table 2 of DS13895 Rev 2. This value is measured at Tamb = 25 °C and represents the maximum voltage seen by downstream circuitry during such transients.
Is SM50T19AY bidirectional or unidirectional?
SM50T19AY is a unidirectional TVS diode, indicated by the "AY" suffix (vs. "CAY" for bidirectional versions). It conducts only during reverse-biased overvoltage events and blocks forward current up to its rated standoff voltage of 16 V.
Does SM50T19AY meet AEC-Q101 requirements for automotive use?
Yes - SM50T19AY is explicitly qualified to AEC-Q101 standards, including stress tests for temperature cycling, high-temperature operating life, and ESD robustness. Its qualification is documented in the device's official datasheet (DS13895) and supported by STMicroelectronics' automotive product certification program.
What is the recommended PCB footprint for SM50T19AY?
The recommended footprint follows IPC7531 guidelines and matches the JEDEC DO-214AB (SMC) outline: 5.11 mm × 8.19 mm pad length, 3.14 mm pad width, and 1.54 mm solder mask opening per terminal. Figure 24 in DS13895 Rev 2 provides exact dimensions and thermal relief recommendations for optimal thermal performance.
SM50T19AY Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AB, SMC
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 16V (Max)
- Voltage - Breakdown (Min):
- 17.9V
- Voltage - Clamping (Max) @ Ipp:
- 26V
- Current - Peak Pulse (10/1000µs):
- 192A
- Power - Peak Pulse:
- 5000W (5kW)
- 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
SM50T19AY FAQ
1.How can I place an order for SM50T19AY through Aetrix?
Please submit a Request for Quotation (RFQ) for SM50T19AY 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 SM50T19AY reliable?
The price and inventory of SM50T19AY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM50T19AY is usually 5 days.
3.What payment methods are accepted for SM50T19AY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM50T19AY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM50T19AY?
SM50T19AY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM50T19AY 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 SM50T19AY?
For technical support, including SM50T19AY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM50T19AY requirements.
6.How does Aetrix verify that SM50T19AY is sourced from the original manufacturer or authorized distributors?
All SM50T19AY 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 SM50T19AY meets industry standards.
7.What is the process for return or replacement of SM50T19AY?
All SM50T19AY units undergo pre-shipment inspection (PSI). If there is an issue with SM50T19AY, 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 SM50T19AY part is unused and in its original packaging.
Return procedure for SM50T19AY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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