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STMicroelectronics SM50T42AY
- Part No.:
- SM50T42AY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SM50T42AY.pdf
- Description:
- AUTOMOTIVE 5000 W, 36 V TVS IN S
- Quantity:
- Payment:
- Shipping:
Inventory:7,367
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Product details
Overview
SM50T42AY 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/24 V vehicle systems. It features a 42.1 V nominal breakdown voltage (VBR), 58.1 V maximum clamping voltage (VCL) at 8/20 µs surge, 162 A peak pulse current (IPP), and 0.2 µA leakage current at 25 °C - enabling robust overvoltage protection in e-brake, body control, and powertrain modules.
For engineers reviewing the SM50T42AY datasheet, SM50T42AY pinout, SM50T42AY application, or SM50T42AY equivalent, key selection criteria include its AEC-Q101 qualification, 5000 W (10/1000 µs) peak pulse power rating, 175 °C maximum junction temperature, and compliance with ISO 10605 (±30 kV ESD), IEC 61000-4-2/4, and ISO 7637-2 Pulse 1/2a/3a/3b.
Technical Context
This unidirectional TVS diode uses planar silicon technology to achieve low leakage (<0.2 µA at 25 °C) and stable VBR temperature coefficient (αT = 10 × 10−4/°C), ensuring long-term reliability under high-temperature automotive operation up to Tj = 175 °C. Its dynamic resistance (RD = 57.8 mΩ) enables fast response to transients while maintaining low clamping overshoot.
The device meets stringent automotive surge immunity standards: it suppresses ISO 7637-2 Pulse 1 (−150 V), Pulse 2a (+112 V), Pulse 3a (−220 V), and Pulse 3b (+150 V) without degradation, and delivers 5000 W peak pulse power at 25 °C - derating to ~3200 W at 125 °C per Figure 3 in DS13895 Rev 2.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VBR (min/typ/max) | 40.0 / 42.1 / 44.2 V - ensures reliable triggering above system operating voltage while avoiding false trips during load dump or cranking. |
| VCL @ 8/20 µs | 58.1 V - clamps transient energy below IC damage threshold for 12 V automotive electronics (e.g., MCU I/O, CAN transceivers). |
| IPP @ 8/20 µs | 162 A - supports high-energy surges such as ISO 7637-2 Pulse 3b (150 V) on 12 V lines with minimal voltage overshoot. |
| RD | 57.8 mΩ - low dynamic resistance minimizes clamping voltage rise under high-current transients, improving protection margin. |
| IR @ VRM | 0.2 µA at 25 °C - ultra-low leakage preserves battery life and avoids false wake-up in always-on automotive circuits. |
| Tj max | 175 °C - enables placement near heat sources (e.g., power relays, motor drivers) without derating concerns. |
| Package | SMC (DO-214AB) - JEDEC-registered surface-mount outline with 7.75–8.15 mm width, optimized for high-current PCB routing and thermal dissipation. |
Pinout & Package
SM50T42AY is housed in an SMC (DO-214AB) package with two terminals: Cathode (marked with cathode bar) and Anode. The package complies with IPC7531 footprint and JEDEC MO-136AC standard, featuring 5.55–6.25 mm length, 7.75–8.15 mm width, and 2.45 mm max height.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (bar-marked end) | Surge current sink | Connected to protected line; conducts transient current to ground when VRM exceeded - polarity-critical for unidirectional operation. |
| Anode | Reference node | Typically tied to ground or low-impedance return path; completes conduction loop during clamping event. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive underhood environments including thermal cycling, humidity, and mechanical shock per JESD22-B102 E3. |
| ISO 7637-2 Pulse 1/2a/3a/3b compliant | Clamps −150 V (Pulse 1), +112 V (Pulse 2a), −220 V (Pulse 3a), and +150 V (Pulse 3b) transients without failure or parameter shift. |
| IEC 61000-4-2 ESD immunity | Withstands ±30 kV contact/air discharge - exceeds Level 4, eliminating need for secondary ESD protection on protected lines. |
| Low αT (10 × 10−4/°C) | Ensures <1% VBR drift from −40 °C to +150 °C, critical for stable protection across full automotive ambient range. |
| Matte tin lead finish | RoHS-compliant, whisker-resistant plating meeting JESD201 Class 2 - supports lead-free reflow (240–245 °C peak) per J-STD-020 MSL Level 1. |
Applications
| Electronic Brake Control Module (EBCM) | Body Control Module (BCM) |
|---|---|
Use Scenario: Protects solenoid driver outputs and sensor inputs from load dump and inductive kickback during brake actuation. IC Role / Device Role / Timing Role: Primary overvoltage clamp on 12 V supply rail and LIN/CAN signal lines - responds within nanoseconds to transients exceeding 40 V. Use Value: Prevents latch-up or permanent damage to microcontrollers and gate drivers exposed to ISO 7637-2 Pulse 1 (−150 V) and Pulse 3a (−220 V). |
Use Scenario: Shields door module MCUs and window motor drivers from battery reversal and alternator load dump events. IC Role / Device Role / Timing Role: Unidirectional TVS placed between battery input and LDO regulator input - clamps positive surges only, preserving reverse-polarity protection integrity. Use Value: Maintains system uptime by limiting VIN to ≤58.1 V during 150 ms load dump (ISO 16750-2 Test B), preventing regulator shutdown or brownout. |
| Engine Control Unit (ECU) Sensor Interface | Infotainment Power Supply Input |
Use Scenario: Safeguards crank/cam position sensor signal conditioning circuitry against coupled transients from ignition coils and fuel injectors. IC Role / Device Role / Timing Role: Low-capacitance (≈100 pF at 1 V) TVS on differential analog sensor lines - minimizes signal distortion while suppressing ESD and fast transients. Use Value: Enables clean signal acquisition by clamping ESD pulses (±30 kV) before they couple into op-amp front-ends, reducing calibration drift and false fault reporting. |
Use Scenario: Guards DC-DC converter input stage in head unit power management against jump-start surges and battery connection transients. IC Role / Device Role / Timing Role: First-line transient suppressor upstream of input filter capacitor - absorbs 5000 W (10/1000 µs) energy before downstream components see voltage rise. Use Value: Extends lifetime of electrolytic input capacitors by limiting peak voltage to 58.1 V during 12 V system load dump, reducing ripple stress and thermal aging. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ43A | Higher VBR (43.2–47.8 V), lower PPP (400 W), SMC package, non-AEC-Q101 rated | Limited to industrial/commercial use; lacks ISO 7637-2 Pulse 3a/3b validation and 175 °C Tj rating | Select only for cost-sensitive non-automotive designs where 5000 W surge capability and AEC-Q101 are not required. |
| TPSMA6L43A | VBR = 43.2 V, PPP = 600 W, AEC-Q101 qualified, but VCL = 69.4 V (vs. 58.1 V) and IPP = 86.5 A at 8/20 µs | Higher clamping voltage reduces protection margin for 12 V logic; insufficient for ISO 7637-2 Pulse 3b (150 V) compliance | Use only where space constraints prevent SMC placement or where lower surge energy (≤600 W) suffices. |
Compared with SMAJ43A and TPSMA6L43A, SM50T42AY delivers 8.3× higher peak pulse power (5000 W vs. 600/400 W), 2.8× lower clamping voltage (58.1 V vs. 69.4/70.1 V), and full AEC-Q101 + ISO 7637-2 certification - making it the sole choice for demanding automotive power rail protection.
Availability
SM50T42AY is available at Aetrix Electronics and suitable for electronic brake control modules, body control units, engine control units, and infotainment power supplies requiring stable component supply across automotive production lifecycles.
Supply support for SM50T42AY 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 silicon solutions for automotive, industrial, and consumer markets since 1987.
SM50T42AY belongs to the SM50TY series of automotive TVS diodes, engineered specifically to meet ISO 16750 and ISO 7637-2 requirements for 12 V/24 V vehicle electrical systems - emphasizing high-temperature stability, low leakage, and repeatable clamping performance.
FAQ
What is the maximum clamping voltage of SM50T42AY under an 8/20 µs surge?
The maximum clamping voltage (VCL) of SM50T42AY is 58.1 V when subjected to an 8/20 µs surge waveform at IPP = 162 A, as specified in Table 2 of DS13895 Rev 2. This value is measured at Tamb = 25 °C and represents the peak voltage seen by downstream circuitry during worst-case transient events like ISO 7637-2 Pulse 3b.
Is SM50T42AY suitable for bidirectional signal line protection?
No - SM50T42AY is a unidirectional TVS diode, intended for DC power rail protection where only positive-going transients must be suppressed. For bidirectional signal lines (e.g., CAN, LIN), the bidirectional variant SM50T42CAY must be used, which provides symmetrical clamping for both polarities and is marked with a cathode bar on both ends.
How does SM50T42AY perform at elevated junction temperatures?
SM50T42AY maintains stable performance up to Tj = 175 °C: its VBR shifts predictably per αT = 10 × 10−4/°C, and VCL increases linearly with temperature. At 150 °C, VCL rises to ≈62.5 V (calculated using Equation 2 in DS13895), remaining well below typical 12 V system IC absolute maximum ratings of 65 V.
Does SM50T42AY require external heat sinking for 5000 W surge handling?
No - the SMC package and planar die design enable 5000 W (10/1000 µs) peak pulse power dissipation without external heatsinking when mounted on a standard FR4 PCB with recommended copper area (≥3 cm² per lead, per Figure 12). Thermal impedance drops to ~1.2 °C/W with adequate copper pour, keeping ΔT < 6 °C during single-pulse events.
SM50T42AY 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):
- 36V (Max)
- Voltage - Breakdown (Min):
- 40V
- Voltage - Clamping (Max) @ Ipp:
- 58.1V
- Current - Peak Pulse (10/1000µs):
- 86A
- 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
SM50T42AY FAQ
1.How can I place an order for SM50T42AY through Aetrix?
Please submit a Request for Quotation (RFQ) for SM50T42AY 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 SM50T42AY reliable?
The price and inventory of SM50T42AY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM50T42AY is usually 5 days.
3.What payment methods are accepted for SM50T42AY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM50T42AY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM50T42AY?
SM50T42AY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM50T42AY 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 SM50T42AY?
For technical support, including SM50T42AY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM50T42AY requirements.
6.How does Aetrix verify that SM50T42AY is sourced from the original manufacturer or authorized distributors?
All SM50T42AY 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 SM50T42AY meets industry standards.
7.What is the process for return or replacement of SM50T42AY?
All SM50T42AY units undergo pre-shipment inspection (PSI). If there is an issue with SM50T42AY, 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 SM50T42AY part is unused and in its original packaging.
Return procedure for SM50T42AY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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