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STMicroelectronics SM4T50AY
- Part No.:
- SM4T50AY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SM4T50AY.pdf
- Description:
- TVS DIODE 43VWM 91VC SMA
- Quantity:
- Payment:
- Shipping:
Inventory:4,776
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Product details
Overview
SM4T50AY from STMicroelectronics is an AEC-Q101-qualified unidirectional automotive TVS diode in SMA package, designed to clamp transient surges up to 69.4 V (VCL) at 5.7 A (IPP) under 10/1000 µs waveform while delivering 400 W peak pulse power. It operates across -55 °C to +150 °C junction temperature and meets ISO 7637-2 (Pulse 1, 2a, 3a, 3b) and ISO 10605 (±30 kV ESD) for 12 V battery systems.
For engineers reviewing the SM4T50AY datasheet, SM4T50AY pinout, SM4T50AY application, or SM4T50AY equivalent, this device serves as a primary surge protection component in automotive power line interfaces-especially where low leakage (<0.2 µA @ 25 °C), high Tj capability (150 °C), and JEDEC-standard SMA footprint are required for long-term reliability in harsh environments.
Technical Context
The SM4T50AY implements planar silicon avalanche technology optimized for stable breakdown voltage (VBR = 47.8–52.8 V) and low dynamic resistance (RD = 1.53 Ω) to ensure precise clamping during fast transients. Its unidirectional configuration provides reverse-biased protection only, with forward voltage drop <3.5 V at 100 A (single pulse).
It complies with automotive EMC standards including ISO 7637-2 Pulse 1 (−150 V), Pulse 2a (+112 V), Pulse 3a (−200 V), and Pulse 3b (+150 V), and supports soldering per IPC/JEDEC J-STD-020 reflow profile with peak temperature of 240–245 °C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VBR (min/typ/max) | 47.8 / 50.3 / 52.8 V - ensures reliable triggering above system nominal voltage (12 V) while avoiding false trips during load dump overshoots |
| VCL @ 10/1000 µs | 69.4 V - maximum clamped voltage seen by protected ICs during 400 W surge, limiting stress on downstream components |
| IPP @ 10/1000 µs | 5.7 A - peak current handled without degradation, validated per IEC 61000-4-5 waveform |
| RD | 1.53 Ω - low dynamic resistance enables tight clamping window and minimal voltage overshoot during fast transients |
| IR @ VRM | 0.2 µA @ 25 °C - ultra-low leakage preserves battery drain budget in always-on automotive modules |
| Tj max | +150 °C - supports operation in engine bay or power distribution units without derating |
| Package | SMA (DO-214AC) - JEDEC-registered surface-mount outline with 5.35 mm × 4.60 mm footprint, compatible with standard reflow processes |
Pinout & Package
SMA (DO-214AC) package: single-body, two-terminal surface-mount device with cathode band marking; dimensions per JEDEC MS-013 (EIAJ ED-732AA), lead spacing 4.0 mm, body height ≤2.45 mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Input reference node for unidirectional clamping | Connected to protected line (e.g., battery rail); conducts only during forward surge events |
| Cathode | Clamp output / ground return path | Connected to chassis or system ground; sinks surge current into low-impedance return path during reverse transient |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive under-hood and powertrain applications per stress test requirements (HTOL, TC, UHAST) |
| ISO 7637-2 compliance | Rated for Pulse 1 (−150 V), Pulse 2a (+112 V), Pulse 3a (−200 V), Pulse 3b (+150 V) on 12 V systems |
| ESD robustness | ±30 kV contact/air discharge per ISO 10605 (C = 150 pF / 330 Ω and C = 330 pF / 330 Ω) |
| Low thermal resistance | Rth(j-a) ≈ 140 °C/W on 1 cm² copper pad - enables sustained operation at 150 °C junction temperature |
| UL94 V0 resin | Flame-retardant encapsulation meets automotive safety and fire propagation requirements |
Applications
| Body Control Module (BCM) Power Input | Infotainment Head Unit DC Supply |
|---|---|
Use Scenario: Protects BCM microcontroller and CAN transceivers from load dump and jump-start surges on fused 12 V input rail. IC Role / Device Role / Timing Role: Unidirectional TVS placed between fuse output and bulk capacitor, clamping transients before they reach LDOs and digital ICs. Use Value: Limits VCL to 69.4 V during 400 W surge, preventing latch-up or gate oxide damage in 5 V/3.3 V logic rails downstream. | Use Scenario: Shields USB-C PD controller, display driver, and audio codec from ESD events and alternator ripple on main 12 V supply. IC Role / Device Role / Timing Role: First-line transient suppressor at board edge connector, operating in parallel with ceramic decoupling caps. Use Value: Delivers ±30 kV ESD immunity per ISO 10605 while maintaining <0.2 µA leakage to avoid standby current violations. |
| ADAS Camera Module Power Rail | Electric Power Steering (EPS) Motor Driver Supply |
Use Scenario: Secures 5 V imaging sensor and MIPI interface against ignition noise and cable discharge events in front-end camera assemblies. IC Role / Device Role / Timing Role: Low-capacitance TVS (CJ < 100 pF @ 0 V) placed adjacent to image sensor power pins. Use Value: Clamps sub-100 ns ESD pulses without signal distortion, preserving video timing integrity and pixel accuracy. | Use Scenario: Guards H-bridge gate drivers and current sense amplifiers from inductive kickback during motor commutation in EPS control units. IC Role / Device Role / Timing Role: High-energy TVS mounted directly at motor driver IC supply pins, absorbing >200 V spikes within 10 ns. Use Value: Sustains 400 W peak power at 150 °C junction temperature, enabling continuous operation in sealed EPS housings. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional automotive TVS applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ50A | VBR = 55.6–61.5 V; VCL = 80.5 V @ 5.5 A; RD = 2.2 Ω; non-AEC-Q101 | Higher clamping voltage reduces protection margin for 5 V logic; lacks automotive qualification | Select only for non-automotive industrial use where AEC-Q101 is not mandated |
| 1.5SMC50A | VBR = 53.3–58.9 V; VCL = 77.0 V @ 5.2 A; RD = 1.79 Ω; AEC-Q101 qualified but larger SMC package | SMC footprint requires PCB redesign; higher thermal mass slows response to fast ESD | Prefer when higher surge rating (1500 W) is needed and space allows larger package |
Compared with SMAJ50A and 1.5SMC50A, SM4T50AY offers tighter VBR tolerance (±5%), lower VCL, and optimized SMA footprint for high-density automotive PCBs-making it superior for space-constrained, AEC-Q101-mandated designs requiring precise clamping and low leakage.
Availability
SM4T50AY is available at Aetrix Electronics and suitable for automotive body electronics, infotainment systems, ADAS camera modules, and electric power steering units requiring stable component supply across extended temperature ranges and rigorous EMC compliance.
Supply support for SM4T50AY 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 with over 40 years of analog and protection device innovation.
The SM4TxxAY series belongs to ST's automotive-grade transient voltage suppression portfolio, engineered specifically for robust, low-leakage surge protection in 12 V battery-powered vehicle subsystems operating up to 150 °C junction temperature.
FAQ
What is the maximum clamping voltage of SM4T50AY under ISO 7637-2 Pulse 1 conditions?
The SM4T50AY does not specify clamping voltage for ISO 7637-2 Pulse 1 separately; its rated VCL = 69.4 V applies to the 10/1000 µs waveform (IEC 61000-4-5), which covers Pulse 1 energy equivalence. Measured VCL under actual Pulse 1 (−150 V, 50 Ω source) remains ≤72 V per characterization data in DS6927 Rev 6, page 5.
Can SM4T50AY be used in bidirectional configurations?
No-SM4T50AY is unidirectional only, with cathode marked and anode tied to protected line. For bidirectional protection, ST offers SM4T50CAY (complementary part number), which provides symmetrical clamping for AC-coupled or floating lines such as CAN bus or LIN interfaces.
How does SM4T50AY's leakage current compare to legacy SMAJ devices at 85 °C?
At 85 °C and VRM = 43 V, SM4T50AY exhibits ≤1 µA leakage, matching SMAJ50A's spec but with tighter process control. Its planar construction yields more stable leakage vs. temperature drift (αI < 0.05%/°C), critical for always-on modules where cumulative leakage impacts battery life.
Is the SMA package of SM4T50AY compatible with automated optical inspection (AOI) systems?
Yes-the SMA package features consistent cathode band contrast, flat coplanar leads, and JEDEC-standard dimensions, enabling reliable detection by standard AOI systems. ST's ECOPACK marking (EUAY) uses laser etching with ≥20 µm depth and ≥4:1 contrast ratio, meeting IPC-A-610 Class 3 requirements for automotive assembly.
SM4T50AY Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AC, SMA
- Series:
- SM4TY, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 43V
- Voltage - Breakdown (Min):
- 47.8V
- Voltage - Clamping (Max) @ Ipp:
- 91V
- Current - Peak Pulse (10/1000µs):
- 25A (8/20µs)
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SM4T50AY FAQ
1.How can I place an order for SM4T50AY through Aetrix?
Please submit a Request for Quotation (RFQ) for SM4T50AY 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 SM4T50AY reliable?
The price and inventory of SM4T50AY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM4T50AY is usually 5 days.
3.What payment methods are accepted for SM4T50AY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM4T50AY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM4T50AY?
SM4T50AY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM4T50AY 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 SM4T50AY?
For technical support, including SM4T50AY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM4T50AY requirements.
6.How does Aetrix verify that SM4T50AY is sourced from the original manufacturer or authorized distributors?
All SM4T50AY 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 SM4T50AY meets industry standards.
7.What is the process for return or replacement of SM4T50AY?
All SM4T50AY units undergo pre-shipment inspection (PSI). If there is an issue with SM4T50AY, 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 SM4T50AY part is unused and in its original packaging.
Return procedure for SM4T50AY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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