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STMicroelectronics SMA6T68AY
- Part No.:
- SMA6T68AY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMA6T68AY.pdf
- Description:
- TVS DIODE 58.1VWM 121VC SMA
- Quantity:
- Payment:
- Shipping:
Inventory:5,345
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Product details
Overview
SMA6T68AY from STMicroelectronics is a unidirectional 600 W transient voltage suppression (TVS) diode designed for automotive circuit protection against ISO 7637-2 load dump pulses and IEC/ISO ESD events. It features a 68 V standoff voltage (VRM), 92 V max clamping voltage at 6.5 A (10/1000 µs), 0.2 µA leakage at 25 °C, and operates up to 150 °C junction temperature in SMA package.
For engineers reviewing the SMA6T68AY datasheet, SMA6T68AY pinout, SMA6T68AY application, or SMA6T68AY equivalent, key selection criteria include clamping performance under 10/1000 µs surges, low leakage for battery-sensitive systems, AEC-Q101 qualification, and compatibility with ISO 7637-2 Pulse 1 (–150 V), Pulse 2a (+112 V), Pulse 3a (–220 V), and Pulse 3b (+150 V) waveforms.
Technical Context
This TVS diode uses planar silicon technology to achieve stable breakdown behavior and low dynamic resistance (1.5 Ω at 10/1000 µs), enabling precise clamping during fast transients. Its unidirectional configuration provides forward conduction path for reverse-polarity protection while maintaining high impedance in normal operation.
The device meets stringent automotive reliability requirements: AEC-Q101 qualified, MSL Level 1, JESD22-B102 E3 solderability, and whisker-resistant matte tin plating. It complies with ISO 10605 (±30 kV air/contact discharge), IEC 61000-4-2 (Level 4), and ISO 7637-2 (Pulse 1, 2a, 3a, 3b) standards for 12 V and 24 V vehicle electrical systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standoff Voltage (VRM) | 68 V - Maximum continuous reverse operating voltage before significant leakage; defines minimum system operating margin. |
| Breakdown Voltage (VBR) | 64.6 V (typ) at 1 mA - Voltage at which device enters avalanche conduction; ensures reliable triggering before downstream IC damage. |
| Clamping Voltage (VCL) | 92.0 V at 6.5 A (10/1000 µs) - Peak voltage seen by protected circuit during surge; critical for MCU/ECU I/O survivability. |
| Peak Pulse Power | 600 W (10/1000 µs) - Sustained energy-handling capability for slow-rising load dump transients in automotive power nets. |
| Leakage Current | 0.2 µA at 25 °C - Ultra-low standby current preserves battery life in always-on vehicle modules (e.g., CAN gateways, body controllers). |
| Junction Temperature | –55 °C to +150 °C - Enables deployment in engine bay, under-hood, or transmission control units without derating. |
| Dynamic Resistance | 1.50 Ω - Low RD minimizes voltage overshoot during high-di/dt events; improves clamping accuracy across temperature. |
Pinout & Package
Package: SMA (DO-214AC), JEDEC-registered surface-mount outline with matte tin-plated leads; footprint per IPC7531; thermal resistance Rth(j-a) = 4.5 °C/W on 1 cm² copper (FR4).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (marked band) | Surge current sink | Connected to protected line (e.g., LIN bus, sensor supply); conducts avalanche current to ground during overvoltage. |
| Anode | Reference / ground return | Connected to system ground plane; completes low-inductance path for transient energy dissipation. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive-grade reliability including temperature cycling, humidity bias, and mechanical shock per JESD47. |
| Low leakage current | 0.2 µA at 25 °C enables use in always-on circuits without measurable battery drain over years of operation. |
| High-temperature operation | 150 °C Tj(max) supports placement near heat sources (e.g., powertrain ECUs) without thermal derating. |
| ISO 7637-2 compliance | Withstands Pulse 1 (–150 V), Pulse 2a (+112 V), Pulse 3a (–220 V), and Pulse 3b (+150 V) without degradation. |
| ESD robustness | ±30 kV contact/air discharge per ISO 10605 (C = 150 pF / 330 Ω and C = 330 pF / 330 Ω) protects infotainment and ADAS interfaces. |
Applications
| Engine Control Unit (ECU) Power Input | LIN Bus Transceiver Protection |
|---|---|
Use Scenario: Protecting 12 V supply rail of gasoline/diesel engine control units against alternator load dump and battery reversal. IC Role / Device Role / Timing Role: Unidirectional TVS placed between battery feed and LDO input to clamp transients before they reach microcontroller power domain. Use Value: Prevents brownout-induced MCU resets and internal LDO failure during ISO 7637-2 Pulse 1 (–150 V) and Pulse 2a (+112 V) events. | Use Scenario: Safeguarding LIN physical layer transceivers (e.g., TJA1020) from ESD and coupled noise on vehicle wiring harnesses. IC Role / Device Role / Timing Role: TVS connected between LIN line and ground to suppress ±30 kV ESD strikes and fast transients induced by nearby solenoid switching. Use Value: Maintains LIN communication integrity during assembly-line ESD events and service-center hot-plug operations without latch-up or parametric shift. |
| Body Control Module (BCM) Sensor Inputs | ADAS Camera Power Rail |
Use Scenario: Shielding analog sensor inputs (e.g., ambient temperature, rain sensor) in BCMs from harness-coupled transients and ESD. IC Role / Device Role / Timing Role: TVS placed at connector entry point to shunt surge energy away from precision op-amps and ADC front-ends. Use Value: Ensures sensor signal fidelity remains within ±0.5% error band after repeated ISO 10605 ±30 kV discharges, avoiding false fault codes. | Use Scenario: Protecting 5 V or 3.3 V camera module power rails in rear-view or surround-view systems exposed to harsh under-vehicle environments. IC Role / Device Role / Timing Role: TVS deployed upstream of DC-DC converter to absorb ISO 7637-2 Pulse 3a (–220 V) and Pulse 3b (+150 V) spikes induced by ABS actuation. Use Value: Eliminates image corruption or frame loss during braking events by limiting rail collapse to <1.2 V below nominal for <10 µs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMA6T68A | Same electrical specs but non-AEC-Q101 qualified; lacks automotive reliability testing and MSL Level 1 rating. | Not suitable for production automotive ECUs; acceptable for industrial or consumer prototypes. | Select only if AEC-Q101 compliance is not required and cost sensitivity outweighs long-term field reliability. |
| SMC6T68A | Same VRM/VBR/VCL but in larger SMC (DO-214AB) package; higher thermal mass allows 1500 W peak pulse power (10/1000 µs). | Better suited for high-energy transients in alternator output lines; requires more PCB area and different footprint. | Choose when surge energy exceeds 600 W or board layout permits larger package; avoid if space-constrained or targeting AEC-Q101 certification. |
Compared with SMA6T68A and SMC6T68A, SMA6T68AY delivers certified automotive reliability in the smallest qualified footprint, making it optimal for space-limited ECU designs where ISO 7637-2 immunity and zero-field-failure targets are mandatory.
Availability
SMA6T68AY is available at Aetrix Electronics and suitable for engine control units, LIN bus nodes, body control modules, and ADAS camera power supplies requiring stable component supply across multi-year automotive production cycles.
Supply support for SMA6T68AY 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 microcontrollers, power devices, sensors, and analog ICs for automotive, industrial, and consumer markets.
The SMA6TY series belongs to ST's automotive-grade Transil™ TVS portfolio, engineered specifically to meet ISO 7637-2 and ISO 10605 immunity requirements in 12 V/24 V vehicle networks without compromising leakage or thermal stability.
FAQ
What is the maximum clamping voltage of SMA6T68AY under a 10/1000 µs surge?
The maximum clamping voltage is 92.0 V at 6.5 A for a 10/1000 µs waveform, measured at 25 °C. This value increases with junction temperature using the αT coefficient of 10.4 × 10−4/°C; at 125 °C, VCL ≈ 99.5 V. The clamping performance is validated per IEC 61000-4-5 test conditions and directly limits stress on downstream regulators and MCUs.
Is SMA6T68AY bidirectional or unidirectional?
SMA6T68AY is unidirectional, indicated by the "A" suffix in its order code (vs. "CAY" for bidirectional). It conducts only in reverse-bias avalanche mode and blocks forward current up to its rated peak forward voltage (1.3 V at 10 A). This configuration is ideal for protecting positive-supply rails where polarity reversal is not expected.
Does SMA6T68AY require derating at elevated ambient temperatures?
Yes - its peak pulse power must be derated above 25 °C ambient, following the curve in Figure 3 of DS6931. At 85 °C ambient, 10/1000 µs power capability drops to ~70% of 600 W (≈420 W). Derating is calculated using junction temperature (Tj = Tamb + Ppk × Rth(j-a)) and confirmed via thermal simulation on the recommended 1 cm² copper footprint.
Can SMA6T68AY replace SMA6T68A in an existing design?
Yes, SMA6T68AY is a direct drop-in replacement for SMA6T68A in terms of pinout, footprint, and electrical parameters. However, SMA6T68AY adds AEC-Q101 qualification, MSL Level 1, and enhanced ESD robustness - making it mandatory for new automotive designs but optional for legacy industrial boards where qualification is not enforced.
SMA6T68AY Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AC, SMA
- Series:
- SMA6TY, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 58.1V
- Voltage - Breakdown (Min):
- 64.6V
- Voltage - Clamping (Max) @ Ipp:
- 121V
- Current - Peak Pulse (10/1000µs):
- 33A (8/20µs)
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMA6T68AY FAQ
1.How can I place an order for SMA6T68AY through Aetrix?
Please submit a Request for Quotation (RFQ) for SMA6T68AY 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 SMA6T68AY reliable?
The price and inventory of SMA6T68AY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMA6T68AY is usually 5 days.
3.What payment methods are accepted for SMA6T68AY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMA6T68AY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMA6T68AY?
SMA6T68AY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMA6T68AY 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 SMA6T68AY?
For technical support, including SMA6T68AY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMA6T68AY requirements.
6.How does Aetrix verify that SMA6T68AY is sourced from the original manufacturer or authorized distributors?
All SMA6T68AY 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 SMA6T68AY meets industry standards.
7.What is the process for return or replacement of SMA6T68AY?
All SMA6T68AY units undergo pre-shipment inspection (PSI). If there is an issue with SMA6T68AY, 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 SMA6T68AY part is unused and in its original packaging.
Return procedure for SMA6T68AY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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