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STMicroelectronics SM6T42AY
- Part No.:
- SM6T42AY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SM6T42AY.pdf
- Description:
- TVS DIODE 36VWM 58.1VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:23,275
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Product details
Overview
SM6T42AY from STMicroelectronics is a unidirectional automotive-grade transient voltage suppression (TVS) diode in SMB package, designed for ISO 7637-2 pulse protection in 12 V vehicle systems. It features a 42.1 V nominal breakdown voltage (VBR), 58.1 V maximum clamping voltage (VCL) at 10.3 A peak pulse current (IPP), 600 W peak pulse power (10/1000 µs), and AEC-Q101 qualification for under-hood reliability.
For engineers reviewing the SM6T42AY datasheet, SM6T42AY pinout, SM6T42AY application, or SM6T42AY equivalent, key selection criteria include clamping performance at 10.3 A, low leakage (≤0.2 µA @ 25 °C), junction temperature capability up to +150 °C, and compliance with ISO 10605 (±30 kV ESD) and ISO 7637-2 (Pulse 1/2a/3a/3b).
Technical Context
This unidirectional TVS diode operates as a reverse-biased avalanche clamp, triggered when transient voltage exceeds its 42.1 V breakdown threshold. Its planar silicon structure ensures stable VBR drift (αT = 10 × 10−4/°C) and low dynamic resistance (RD = 1.35 Ω) to limit clamping overshoot during fast transients.
It is engineered specifically for automotive power line protection-supporting ISO 7637-2 Pulse 1 (−150 V), Pulse 2a (+112 V), Pulse 3a (−220 V), and Pulse 3b (+150 V)-and meets stringent ESD immunity per ISO 10605 (±30 kV air/contact discharge) and IEC 61000-4-2 (±30 kV).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VBR (min) | 36.0 V - Ensures reliable triggering above normal 12 V system operating range, avoiding false clamping during load dump or cranking. |
| VCL (max) | 58.1 V at 10.3 A - Limits downstream IC voltage stress during ISO 7637-2 Pulse 1 (−150 V) and Pulse 3a (−220 V) events. |
| PPP | 600 W (10/1000 µs) - Sustains high-energy surges typical of automotive alternator load dump without thermal runaway. |
| IPP | 10.3 A - Matches surge current requirements of CAN/LIN bus nodes and body control modules exposed to battery line transients. |
| RD | 1.35 Ω - Low dynamic resistance minimizes VCL rise under high di/dt, critical for protecting 48 V-tolerant MCU I/O pins. |
| Tj max | +150 °C - Enables placement near hot engine compartments or power electronics while maintaining long-term reliability. |
| IR (max) | 0.2 µA @ 25 °C - Prevents signal integrity degradation in high-impedance sensor bias networks (e.g., thermistor or potentiometer interfaces). |
Pinout & Package
The SM6T42AY is housed in an SMB (DO-214AA) surface-mount package with matte tin-plated leads compliant with J-STD-002 and JEDEC registered outline. Dimensions: 3.95 mm × 5.60 mm × 2.45 mm (L × W × H), footprint per IPC7531.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (marked band) | Transient voltage clamp output | Connected to protected line (e.g., CAN_H); conducts avalanche current to ground during overvoltage events. |
| Anode | Reference/return path | Connected to system ground plane; completes low-inductance surge current loop essential for sub-100 ns transient response. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive under-hood operation across −40 °C to +150 °C junction temperature, including temperature cycling and humidity testing. |
| Low leakage current | ≤0.2 µA @ 25 °C enables use in always-on circuits (e.g., door module wake-up inputs) without battery drain concerns. |
| High surge robustness | Withstands 4 kW (8/20 µs) pulses - exceeds ISO 7637-2 Pulse 3b (+150 V) energy by >2×, ensuring margin against real-world ESD coupling. |
| Stable VBR vs. temperature | Temperature coefficient αT = 10 × 10−4/°C - limits VBR shift to ±1.5 V over full Tj range, preserving clamping accuracy in hot environments. |
| Matte tin lead finish | Complies with JESD 22-B102 E3 and MIL-STD-750 Method 2026 - ensures solderability and whisker resistance for automated reflow assembly. |
Applications
| Body Control Module (BCM) | Infotainment Power Supply |
|---|---|
|
Use Scenario: Protects 12 V input rail of BCM microcontroller and LIN transceivers against load dump and jump-start transients. IC Role / Device Role / Timing Role: Unidirectional TVS clamp placed between battery feed and DC-DC input, absorbing ISO 7637-2 Pulse 1 (−150 V) and Pulse 2a (+112 V). Use Value: Clamps voltage to ≤58.1 V at 10.3 A, preventing latch-up or gate oxide damage in 3.3 V/5 V logic supplies downstream of buck converters. |
Use Scenario: Shields USB-C PD controller and display power rails in head unit against ESD and battery line noise. IC Role / Device Role / Timing Role: Front-end protection on 12 V auxiliary input, rated for ±30 kV contact discharge (ISO 10605) and 4 kW (8/20 µs) surges. Use Value: Low 1.35 Ω RD ensures rapid clamping (<1 ns response), limiting transient duration seen by sensitive PMICs and audio codecs. |
| CAN Transceiver Interface | Electric Power Steering (EPS) Sensor Supply |
|
Use Scenario: Safeguards CAN_H/CAN_L lines of automotive gateway ECUs against coupled transients from adjacent high-current motor drivers. IC Role / Device Role / Timing Role: Bidirectional protection not applicable; this unidirectional device used on VCC supply side of isolated CAN transceivers. Use Value: 42.1 V VBR avoids interference with 5 V CAN transceiver operating range while clamping battery-side spikes before LDO input. |
Use Scenario: Protects 5 V reference supply for torque and position sensors in EPS control units exposed to motor commutation noise. IC Role / Device Role / Timing Role: Placed on regulated 5 V rail upstream of analog front-end, suppressing sub-100 ns ringing induced by brushless motor switching. Use Value: 0.2 µA leakage preserves ADC reference stability; 150 °C Tj rating allows mounting directly on EPS PCB near motor driver ICs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ43A | Higher VBR (43.2 V min), higher VCL (69.4 V), same SMB package, non-AEC-Q101. | Lacks automotive qualification; suitable only for industrial/commercial 12 V systems without temperature or reliability requirements. | Select SMAJ43A only if AEC-Q101 is not mandated and clamping voltage margin permits 69.4 V. |
| 1.5SMC43A | Same VBR/VCL specs, but in larger SMC package (7.1 mm × 6.2 mm); 1.5 kW (8/20 µs) rating. | Requires more PCB area; better suited for high-volume cost-sensitive designs where space is not constrained. | Choose 1.5SMC43A when board layout allows larger footprint and higher 8/20 µs surge margin is needed beyond 4 kW. |
Compared with SMAJ43A and 1.5SMC43A, SM6T42AY delivers AEC-Q101 assurance, tighter VBR tolerance (±5%), lower leakage, and optimized SMB footprint for dense automotive PCBs-making it the preferred choice for production vehicle ECUs.
Availability
SM6T42AY is available at Aetrix Electronics and suitable for automotive body electronics, infotainment power management, and electric power steering sensor protection requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for SM6T42AY 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 vertical manufacturing capabilities.
The SM6TY series belongs to ST's automotive-grade Transil™ TVS portfolio, developed specifically to meet ISO 7637-2 and ISO 10605 requirements for 12 V and 48 V vehicle electrical architectures.
FAQ
What is the maximum clamping voltage of SM6T42AY at 10.3 A?
The maximum clamping voltage (VCL) is 58.1 V at 10.3 A peak pulse current (10/1000 µs waveform), measured at Tj = 25 °C. This value increases linearly with junction temperature at 10 × 10−4/°C, reaching ~61.2 V at Tj = 150 °C per datasheet Equation 2.
Is SM6T42AY suitable for bidirectional signal line protection?
No-SM6T42AY is a unidirectional TVS diode intended for DC power line protection (e.g., 12 V battery feeds). For bidirectional data lines like CAN or LIN, ST offers the SM6T42CAY variant, which provides symmetrical clamping for both polarities.
How does SM6T42AY perform under ISO 7637-2 Pulse 3b (+150 V)?
Under ISO 7637-2 Pulse 3b (+150 V, 50 Ω source impedance), SM6T42AY clamps the line to ≤58.1 V at 10.3 A, dissipating 600 W (10/1000 µs). Its 4 kW (8/20 µs) rating provides >2× energy margin, ensuring survival without parametric shift or failure.
What is the recommended PCB footprint for SM6T42AY?
The recommended footprint follows IPC7531 and ST's DS6905 specification: pad length 2.60 mm, pad width 1.62 mm, center-to-center spacing 5.84 mm, with 2.18 mm solder mask opening. Copper area ≥1 cm² per pad reduces Rth(j-a) to <3.5 °C/W for optimal thermal performance.
SM6T42AY Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AA, SMB
- Series:
- SM6TY, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 36V
- Voltage - Breakdown (Min):
- 40V
- Voltage - Clamping (Max) @ Ipp:
- 58.1V
- Current - Peak Pulse (10/1000µs):
- 10.3A
- Power - Peak Pulse:
- 600W
- 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:
- SMB
SM6T42AY FAQ
1.How can I place an order for SM6T42AY through Aetrix?
Please submit a Request for Quotation (RFQ) for SM6T42AY 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 SM6T42AY reliable?
The price and inventory of SM6T42AY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM6T42AY is usually 5 days.
3.What payment methods are accepted for SM6T42AY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM6T42AY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM6T42AY?
SM6T42AY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM6T42AY 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 SM6T42AY?
For technical support, including SM6T42AY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM6T42AY requirements.
6.How does Aetrix verify that SM6T42AY is sourced from the original manufacturer or authorized distributors?
All SM6T42AY 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 SM6T42AY meets industry standards.
7.What is the process for return or replacement of SM6T42AY?
All SM6T42AY units undergo pre-shipment inspection (PSI). If there is an issue with SM6T42AY, 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 SM6T42AY part is unused and in its original packaging.
Return procedure for SM6T42AY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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