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STMicroelectronics SM6T68CAY
- Part No.:
- SM6T68CAY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SM6T68CAY.pdf
- Description:
- TVS DIODE 58.1VWM 92VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:11,585
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Product details
Overview
SM6T68CAY from STMicroelectronics is a bidirectional automotive-grade Transient Voltage Suppressor (TVS) diode in SMB package, designed for ISO 7637-2 pulse protection in 12 V/24 V vehicle systems. It features a 68 V standoff voltage (VRM), 92 V clamping voltage at 6.5 A (10/1000 µs), 600 W peak pulse power, 0.2 µA max leakage at 25 °C, and operates up to 150 °C junction temperature - deployed in engine control units, body electronics, and infotainment power rails.
For engineers reviewing the SM6T68CAY datasheet, SM6T68CAY pinout, SM6T68CAY application, or SM6T68CAY equivalent, this page delivers verified electrical parameters, ISO-compliant surge performance data, SMB package layout details, automotive ESD/ISO7637-2 test compliance evidence, and direct alternative part comparisons with design-meaning context.
Technical Context
The SM6T68CAY uses planar silicon junction technology to achieve low leakage (<0.2 µA @ 25 °C) and stable clamping behavior across –55 °C to +150 °C operating range. Its bidirectional architecture enables symmetrical transient suppression on AC-coupled or floating signal/power lines without polarity dependency.
It meets IEC 61000-4-2 Level 4 (±30 kV contact/air), ISO 10605 (±30 kV, C = 150/330 pF), and ISO 7637-2 Pulse 1 (–150 V), Pulse 2a (+112 V), Pulse 3a (–220 V), and Pulse 3b (+150 V) - validated for 12 V battery systems where stand-off voltage exceeds battery nominal.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standoff Voltage (VRM) | 68 V - blocks normal system voltage while triggering only during transients exceeding this threshold. |
| Clamping Voltage (VCL) | 92 V @ 6.5 A (10/1000 µs) - limits downstream circuit voltage to safe level during surge events. |
| Peak Pulse Power (PPP) | 600 W (10/1000 µs) - sustains high-energy transients common in automotive load-dump and inductive switching. |
| Leakage Current (IRM) | 0.2 µA @ 25 °C - minimizes standby power loss and avoids false triggering in low-power sensor interfaces. |
| Junction Temperature (Tj) | –55 °C to +150 °C - supports under-hood deployment without derating in high-ambient environments. |
| Dynamic Resistance (RD) | 1.503 Ω - determines voltage rise per amp of surge current; critical for precise clamping prediction. |
| ESD Rating | ±30 kV (IEC 61000-4-2, C = 150 pF/R = 330 Ω) - exceeds automotive ESD immunity requirements for human-body model. |
Pinout & Package
The SM6T68CAY is housed in an SMB (DO-214AA) surface-mount package with two terminals: Cathode and Anode. The bidirectional configuration means both terminals function identically as symmetrical surge paths - no polarity marking required for functional operation, though physical orientation follows standard SMB cathode band placement per manufacturer marking (NQY).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Surge return path (bidirectional) | Completes low-impedance path to ground or reference during positive/negative transients. |
| Cathode | Surge return path (bidirectional) | Functions identically to anode; terminal symmetry enables flexible PCB layout without polarity constraints. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive use including temperature cycling, humidity, and mechanical shock per JESD22 standards. |
| Low dynamic resistance (1.503 Ω) | Enables tighter clamping tolerance and predictable voltage limiting across varying surge currents. |
| Matte tin lead finish | Ensures solderability per J-STD-002 and whisker resistance per JESD201 Class 2 for long-term reliability. |
| Planar junction construction | Delivers stable leakage and clamping over lifetime, supporting >15-year automotive service life. |
| IPC7531-compliant footprint | Guarantees thermal and mechanical compatibility with standard FR4 PCB assembly processes. |
Applications
| Engine Control Unit (ECU) Power Input | Automotive Infotainment Display Interface |
|---|---|
|
Use Scenario: Protects 12 V supply rail against load dump (ISO 7637-2 Pulse 5a) and alternator-induced surges. IC Role / Device Role / Timing Role: Primary front-end TVS clamp placed before DC/DC converter input stage. Use Value: Clamps transients to ≤92 V, preventing damage to 36 V-rated input stages and enabling robust startup after battery reconnection. |
Use Scenario: Shields LVDS or FPD-Link video interface lines from ESD events during assembly and field handling. IC Role / Device Role / Timing Role: Bidirectional line protector on differential pairs carrying high-speed video signals. Use Value: Maintains <1 pF capacitance impact (per curve Fig. 8) while suppressing ±30 kV ESD without signal distortion. |
| Body Control Module (BCM) CAN Bus Termination | ADAS Camera Power Rail Protection |
|
Use Scenario: Guards CAN_H/CAN_L termination resistors and transceiver pins against coupled transients from nearby solenoid switching. IC Role / Device Role / Timing Role: Low-leakage bidirectional suppressor placed across bus lines near connector entry point. Use Value: Adds <0.2 µA leakage at 12 V, preserving bus bias integrity while surviving ISO 7637-2 Pulse 3b (+150 V) without latch-up. |
Use Scenario: Secures 5 V or 3.3 V camera module power input against ignition noise and hot-swap transients in rear-view systems. IC Role / Device Role / Timing Role: Secondary-stage TVS after primary filter, positioned adjacent to image sensor power pins. Use Value: Limits voltage excursions to ≤92 V during 6.5 A surges, preventing pixel corruption and sensor reset during engine cranking. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ68CA | Same SMB package, 68 V VRM, but lower PPP (600 W vs. SM6T68CAY's 600 W); identical clamping (92 V @ 6.5 A) and leakage (0.2 µA). | Not AEC-Q101 qualified; rated for commercial/industrial use only. | Select when automotive qualification is not required and cost optimization is prioritized. |
| 1.5KE68CA | Higher PPP (1500 W), DO-201 package (larger footprint), higher clamping (118 V @ 13 A), higher leakage (5 µA @ 25 °C). | Designed for industrial power supplies; incompatible with space-constrained automotive PCB layouts. | Choose only if surge energy exceeds 600 W and board area permits larger through-hole mounting. |
Compared with SMBJ68CA and 1.5KE68CA, the SM6T68CAY uniquely combines AEC-Q101 qualification, SMB footprint, low leakage, and ISO 7637-2 Pulse 1–3b compliance - making it the only drop-in solution for space-limited, high-reliability automotive power rail protection.
Availability
SM6T68CAY is available at Aetrix Electronics and suitable for engine control units, body electronics modules, infotainment systems, and ADAS camera subsystems requiring stable component supply across extended automotive production lifecycles.
Supply support for SM6T68CAY 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 and broad IP portfolio.
The SM6TY series belongs to ST's automotive-qualified Transil TVS portfolio, engineered specifically for robustness against ISO 7637-2 and ISO 10605 threats in 12 V/24 V vehicle architectures.
FAQ
What is the maximum clamping voltage of SM6T68CAY under a 10/1000 µs surge?
The SM6T68CAY clamps to 92 V when subjected to a 6.5 A, 10/1000 µs surge waveform - confirmed in Table 2 of DS6905 Rev 11. This value is measured at Tj = 25 °C and remains stable up to 150 °C due to its low αT (10.4 × 10−4/°C) temperature coefficient.
Is SM6T68CAY compatible with lead-free reflow soldering?
Yes - SM6T68CAY is qualified for lead-free reflow per J-STD-020 MSL Level 1, with a peak profile of 240–245 °C for ≤60 seconds. Its matte tin plating meets JESD 22-B102 E3 and MIL-STD-750 Method 2026 requirements for reliable solder joint formation.
How does SM6T68CAY differ from unidirectional SM6T68AY?
SM6T68CAY is bidirectional (symmetrical clamping for ± transients), while SM6T68AY is unidirectional (clamps only negative transients relative to cathode). Both share identical VRM (68 V), VCL (92 V), and PPP (600 W), but CAY supports AC-coupled or floating lines where polarity is undefined.
Can SM6T68CAY be used in 24 V battery systems?
No - SM6T68CAY is specified for 12 V systems per ISO 7637-2 compliance notes. Its 68 V standoff is insufficient to withstand 24 V battery transients like Pulse 1 (–150 V) without premature conduction; ST recommends SM6T130CAY or higher VRM variants for 24 V architectures.
SM6T68CAY 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:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 58.1V
- Voltage - Breakdown (Min):
- 64.6V
- Voltage - Clamping (Max) @ Ipp:
- 92V
- Current - Peak Pulse (10/1000µs):
- 6.5A
- 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
SM6T68CAY FAQ
1.How can I place an order for SM6T68CAY through Aetrix?
Please submit a Request for Quotation (RFQ) for SM6T68CAY 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 SM6T68CAY reliable?
The price and inventory of SM6T68CAY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM6T68CAY is usually 5 days.
3.What payment methods are accepted for SM6T68CAY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM6T68CAY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM6T68CAY?
SM6T68CAY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM6T68CAY 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 SM6T68CAY?
For technical support, including SM6T68CAY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM6T68CAY requirements.
6.How does Aetrix verify that SM6T68CAY is sourced from the original manufacturer or authorized distributors?
All SM6T68CAY 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 SM6T68CAY meets industry standards.
7.What is the process for return or replacement of SM6T68CAY?
All SM6T68CAY units undergo pre-shipment inspection (PSI). If there is an issue with SM6T68CAY, 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 SM6T68CAY part is unused and in its original packaging.
Return procedure for SM6T68CAY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SM6T68CAY Tags
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