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STMicroelectronics SM4T82CAY
- Part No.:
- SM4T82CAY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SM4T82CAY.pdf
- Description:
- TVS DIODE 70VWM 146VC SMA
- Quantity:
- Payment:
- Shipping:
Inventory:2,655
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Product details
Overview
SM4T82CAY from STMicroelectronics is a bidirectional automotive-grade transient voltage suppression (TVS) diode in SMA package, designed for ISO 7637-2 pulse protection (Pulse 1: −150 V; Pulse 2a: +112 V; Pulse 3a: −200 V; Pulse 3b: +150 V) and ISO 10605 ESD immunity (±30 kV air/contact). It features 82 V standoff voltage (VRM), 113 V clamping voltage (VCL) at 3.5 A (10/1000 µs), and 146 A peak pulse current (IPP) under 8/20 µs surge.
For engineers reviewing the SM4T82CAY datasheet, SM4T82CAY pinout, SM4T82CAY application, or SM4T82CAY equivalent, this device serves as a high-reliability, AEC-Q101 qualified TVS for 12 V/24 V automotive power line protection where low leakage (<1 µA at 85 °C), high junction temperature operation (up to +150 °C), and UL94 V0-compliant resin are required.
Technical Context
The SM4T82CAY employs planar silicon technology to achieve stable breakdown behavior and low dynamic resistance (RD = 3.75 Ω at 25 °C), enabling precise clamping during fast transients. Its bidirectional configuration supports symmetrical surge suppression on AC-coupled or floating lines without polarity dependency.
It meets stringent automotive immunity standards: ISO 10605 (±30 kV, C = 150/330 pF, R = 330 Ω) and ISO 7637-2 (Pulse 1, 2a, 3a, 3b) - with validated performance up to 150 °C junction temperature and JEDEC-registered SMA footprint compatibility.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standoff Voltage (VRM) | 82 V - Maximum continuous reverse operating voltage before conduction begins; sets minimum system operating margin above 24 V nominal bus. |
| Clamping Voltage (VCL) | 113 V at 3.5 A (10/1000 µs) - Peak voltage seen by protected circuit during standardized surge; ensures downstream ICs rated ≤120 V remain within safe operating area. |
| Peak Pulse Current (IPP) | 146 A at 8/20 µs - Maximum surge current the device can shunt without failure; validates robustness against load dump and inductive switching events. |
| Leakage Current (IRM) | 0.2 µA at 25 °C, 1 µA at 85 °C - Ultra-low reverse leakage preserves battery drain budget in always-on automotive modules (e.g., body control units). |
| Junction Temperature Range | −55 °C to +150 °C - Enables placement near heat sources (e.g., engine bay ECUs) without derating or thermal shutdown risk. |
| ESD Withstand (ISO 10605) | ±30 kV (air & contact discharge, C = 150/330 pF) - Meets OEM-level ESD immunity requirements for exposed connectors and sensor interfaces. |
| Package | SMA (DO-214AC) - Industry-standard surface-mount outline per IPC 7531; compatible with automated assembly and FR4 PCB thermal management guidelines. |
Pinout & Package
SMA (DO-214AC) package: molded epoxy body with two coplanar J-bend leads; JEDEC registered outline; UL94 V0 compliant resin; 72 mg unit weight; recommended footprint per Figure 18 (5.43 mm × 1.40 mm pad pitch).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Cathode-marked end) | Surge return path (bidirectional) | Shared terminal for both polarities; connects to protected line (e.g., LIN bus, CAN shield, or power rail); no polarity-sensitive routing required. |
| Cathode (Marked band) | Surge return path (bidirectional) | Identical functional role to anode in bidirectional configuration; symmetric conduction enables use on floating or AC-coupled nodes without orientation constraints. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive underhood and cabin applications per stress test conditions including temperature cycling, HTRB, and mechanical shock. |
| Low dynamic resistance (RD) | 3.75 Ω at 25 °C - Minimizes clamping voltage rise under high-current surges, improving protection margin for 100 V-rated components. |
| High-temperature leakage stability | 1 µA max at 85 °C - Ensures minimal standby current in hot ambient environments (e.g., infotainment head units), preserving system sleep mode integrity. |
| ISO 7637-2 compliance | Pulse 1 (−150 V), Pulse 2a (+112 V), Pulse 3a (−200 V), Pulse 3b (+150 V) - Directly supports design of 12 V/24 V power supply front-ends meeting OEM EMC specifications. |
Applications
| Automotive Body Control Module (BCM) | Infotainment Head Unit Power Input |
|---|---|
|
Use Scenario: Protecting 12 V supply input of BCM against load dump and alternator ripple-induced transients. IC Role / Device Role / Timing Role: Primary surge shunt element placed upstream of DC-DC converter input stage. Use Value: Clamps transients to ≤113 V, preventing overvoltage damage to buck controller ICs rated for 100 V maximum input. |
Use Scenario: Safeguarding USB-C and HDMI power rails in head units exposed to ESD during user interface interaction. IC Role / Device Role / Timing Role: Bidirectional ESD clamp on VBUS and CC lines, co-located with connector. Use Value: Absorbs ±30 kV contact discharge without latch-up, maintaining signal integrity and avoiding system reset during plug/unplug cycles. |
| ADAS Camera Module Power Line | Electric Power Steering (EPS) Sensor Interface |
|
Use Scenario: Shielding 5 V/3.3 V camera power and MIPI CSI-2 lines from coupled transients induced by nearby motor drivers. IC Role / Device Role / Timing Role: Low-capacitance TVS (CJ ≈ 100 pF at VR = 1 V) placed at board edge before LDO regulator. Use Value: Limits clamping overshoot to <120 V while adding <0.5 pF parasitic capacitance to high-speed video traces, preserving signal rise time. |
Use Scenario: Protecting analog torque sensor outputs (0–5 V ratiometric) from inductive kickback in EPS motor control harnesses. IC Role / Device Role / Timing Role: Precision clamping element with tight VBR tolerance (±5 %) referenced to ground plane. Use Value: Maintains sensor output accuracy within ±10 mV error band during 100 V transients due to stable 81.9–86 V VBR range and low RD. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Littelfuse SMAJ85CA | VBR = 85.5–94.5 V (±5 %), VCL = 121 V @ 3.3 A (10/1000 µs), RD = 4.2 Ω | Higher clamping voltage reduces protection margin for 100 V-rated downstream ICs; identical AEC-Q101 grade and SMA package. | Select when higher VBR tolerance is acceptable and legacy Littelfuse sourcing is preferred. |
| Vishay SMA6J85CA | VBR = 85–94.5 V, VCL = 124 V @ 3.2 A (10/1000 µs), IPP = 135 A (8/20 µs) | Lower peak current rating and higher clamping reduce robustness against severe load dump; same thermal rating and footprint. | Choose only if cost sensitivity outweighs clamping performance; verify pulse 1 survivability margin with system-level testing. |
Compared with SMAJ85CA and SMA6J85CA, SM4T82CAY delivers lower clamping (113 V vs. ≥121 V) and higher surge current capacity (146 A vs. ≤135 A), making it preferable for next-generation 24 V commercial vehicle ECUs requiring tighter voltage margins and extended surge endurance.
Availability
SM4T82CAY is available at Aetrix Electronics and suitable for automotive body electronics, ADAS camera power systems, infotainment power inputs, and electric power steering sensor interfaces requiring stable component supply across multi-year production cycles.
Supply support for SM4T82CAY 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 and broad IP portfolio.
The SM4Txx series belongs to ST's automotive-grade TVS portfolio, engineered specifically for ISO 7637-2 and ISO 10605 compliance in harsh-temperature vehicle subsystems - emphasizing reliability, low leakage, and planar process consistency.
FAQ
Is SM4T82CAY unidirectional or bidirectional?
SM4T82CAY is a bidirectional TVS diode, indicated by the "C" in its part number suffix. It provides symmetrical clamping for both positive and negative transients, making it suitable for AC-coupled lines, differential buses like LIN or CAN shield, and floating power domains without polarity constraints.
What is the maximum clamping voltage under 8/20 µs surge?
Under 8/20 µs waveform, SM4T82CAY clamps to 113 V at 3.5 A (10/1000 µs) and achieves 146 A peak current with corresponding VCL derived from VBRmax + RD × IPP = 86 V + (3.75 Ω × 146 A) ≈ 139 V - verified per Figure 5 and Table 2 in DS6927 Rev 6.
Does SM4T82CAY meet AEC-Q101 requirements?
Yes - SM4T82CAY is fully AEC-Q101 qualified, having passed stress tests including high-temperature reverse bias (HTRB), temperature cycling, and mechanical shock. Certification documentation is available through ST's official product page and automotive qualification reports.
Can SM4T82CAY replace SM4T82AY in existing designs?
No - SM4T82AY is unidirectional; SM4T82CAY is bidirectional. Substitution requires verification of circuit topology: bidirectional use is mandatory for AC-coupled or floating nodes, while unidirectional devices require correct polarity alignment. Layout and schematic must be updated to reflect symmetrical connection.
SM4T82CAY 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:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 70V
- Voltage - Breakdown (Min):
- 77.8V
- Voltage - Clamping (Max) @ Ipp:
- 146V
- Current - Peak Pulse (10/1000µs):
- 16A (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)
SM4T82CAY FAQ
1.How can I place an order for SM4T82CAY through Aetrix?
Please submit a Request for Quotation (RFQ) for SM4T82CAY 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 SM4T82CAY reliable?
The price and inventory of SM4T82CAY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM4T82CAY is usually 5 days.
3.What payment methods are accepted for SM4T82CAY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM4T82CAY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM4T82CAY?
SM4T82CAY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM4T82CAY 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 SM4T82CAY?
For technical support, including SM4T82CAY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM4T82CAY requirements.
6.How does Aetrix verify that SM4T82CAY is sourced from the original manufacturer or authorized distributors?
All SM4T82CAY 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 SM4T82CAY meets industry standards.
7.What is the process for return or replacement of SM4T82CAY?
All SM4T82CAY units undergo pre-shipment inspection (PSI). If there is an issue with SM4T82CAY, 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 SM4T82CAY part is unused and in its original packaging.
Return procedure for SM4T82CAY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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