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STMicroelectronics SMA6T68CAY
- Part No.:
- SMA6T68CAY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMA6T68CAY.pdf
- Description:
- TVS DIODE 58.1VWM 121VC SMA
- Quantity:
- Payment:
- Shipping:
Inventory:8,925
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Product details
Overview
SMA6T68CAY from STMicroelectronics is a bidirectional automotive-grade transient voltage suppression (TVS) diode in SMA package, designed for ISO 7637-2 pulse protection and ESD immunity per ISO 10605. It features 68 V breakdown voltage (VBR = 68.0 V min), 92.0 V max clamping voltage at 6.5 A (10/1000 µs), 600 W peak pulse power, and operates up to 150 °C junction temperature - deployed in automotive body control modules, infotainment power rails, and CAN/LIN bus interfaces.
For engineers reviewing the SMA6T68CAY datasheet, SMA6T68CAY pinout, SMA6T68CAY application, or SMA6T68CAY equivalent, key selection criteria include bidirectional surge clamping capability, low leakage (<0.2 µA @ 25 °C), AEC-Q101 qualification, and compliance with ISO 7637-2 Pulse 1/2a/3a/3b and ISO 10605 ±30 kV ESD levels.
Technical Context
This TVS diode uses planar silicon technology to achieve stable high-temperature operation (Tj up to +150 °C) and ultra-low leakage current (0.2 µA @ 25 °C). Its bidirectional architecture enables symmetrical clamping for both positive and negative transients without polarity dependency.
The device meets stringent automotive surge standards: ISO 7637-2 Pulse 1 (−150 V), Pulse 2a (+112 V), Pulse 3a (−220 V), and Pulse 3b (+150 V), while delivering 92.0 V clamping at 6.5 A (10/1000 µs) and 121 V at 33.0 A (8/20 µs), with dynamic resistance of 1.50 Ω.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VBR (min) | 68.0 V - ensures reliable turn-on above nominal 60 V system rails, preventing false triggering during load dump or cold-crank conditions. |
| VCL (max, 10/1000 µs) | 92.0 V - limits downstream IC stress during 6.5 A surge, compatible with 75 V-rated automotive components. |
| PPP (10/1000 µs) | 600 W - sustains repeated ISO 7637-2 transients without degradation under standard PCB copper area (1 cm²). |
| IR (max @ 25 °C) | 0.2 µA - minimizes standby power loss in always-on vehicle networks (e.g., LIN sleep mode). |
| Tj (max) | +150 °C - supports under-hood placement near ECUs, motors, or power converters without thermal derating. |
| ESD Rating | ±30 kV (air/contact, C = 150 pF / 330 Ω) - exceeds ISO 10605 Level 4, eliminating need for secondary ESD protection. |
| Package | SMA (DO-214AC) - JEDEC-registered surface-mount outline with matte tin lead finish, MSL Level 1, IPC-7531 compliant footprint. |
Pinout & Package
SMA6T68CAY is housed in a two-terminal SMA (DO-214AC) package with cathode band marking. The device has no polarity-sensitive orientation for bidirectional operation - either terminal may serve as anode or cathode depending on transient polarity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode / Cathode (bidirectional) | Surge current path (reversible) | Both terminals conduct equally during positive or negative transients - eliminates routing constraints in differential or floating lines. |
| Cathode band (marking) | Manufacturing reference only | Indicates terminal 1 per JEDEC DO-214AC; functionally irrelevant for bidirectional use but required for tape-and-reel orientation and automated placement. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive temperature cycling, mechanical shock, and humidity testing - enables direct use in Tier-1 production without requalification. |
| Bidirectional clamping | Single-device protection for AC-coupled or floating buses (e.g., LIN, FlexRay, sensor bridges) without external polarity logic. |
| Low dynamic resistance (RD) | 1.50 Ω - reduces clamping voltage overshoot during fast 8/20 µs surges (121 V @ 33 A), improving margin for 100 V-rated components. |
| High-temperature stability | Leakage remains ≤1 µA up to +85 °C - maintains signal integrity in engine bay or head unit environments without thermal runaway risk. |
| ISO 7637-2 Pulse 3a/3b compliance | Withstands −220 V / +150 V fast transients (200 ns rise time) - protects against ignition noise and alternator switching spikes in 12 V systems. |
Applications
| Body Control Module (BCM) | Infotainment Power Rail |
|---|---|
|
Use Scenario: Protects 12 V input to microcontroller power supply against load dump and jump-start surges. IC Role / Device Role / Timing Role: Primary clamping element placed upstream of DC-DC converter input. Use Value: Limits voltage to ≤92 V during 6.5 A transients, preventing overvoltage shutdown or damage to buck controller ICs rated for 75 V max input. |
Use Scenario: Shields USB-C PD and HDMI power domains from ESD events during user interface interaction. IC Role / Device Role / Timing Role: Board-level ESD suppressor on VBUS and auxiliary power lines. Use Value: Absorbs ±30 kV contact discharge without latch-up, preserving signal integrity and avoiding system reset during hot-plug operations. |
| CAN FD Transceiver Interface | Automotive Sensor Bridge |
|
Use Scenario: Guards CAN_H/CAN_L differential pair against coupled transients induced by nearby solenoid switching. IC Role / Device Role / Timing Role: Common-mode surge clamp between CAN bus and transceiver ground. Use Value: Clamps common-mode surges to <92 V within 100 ns, maintaining CAN FD bit timing integrity and preventing bit errors at 5 Mbps. |
Use Scenario: Protects Wheatstone bridge outputs (e.g., pressure, temperature sensors) from ESD during assembly or service. IC Role / Device Role / Timing Role: Low-capacitance bidirectional clamp across differential analog output pins. Use Value: Adds <10 pF capacitance at 0 V bias - avoids gain error or phase shift in millivolt-level bridge signals while passing ±30 kV ESD. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMA6T68AY | Unidirectional; VBR = 68.0 V min, same VCL/PPP specs | Requires correct polarity placement; unsuitable for AC or floating lines | Select only when protecting DC rails with known polarity and ground-referenced return paths. |
| SMC6T68CAY | Larger SMC (DO-214AB) package; identical electrical specs but higher thermal mass | Lower Rth(j-a) (≈35 °C/W vs. ≈55 °C/W) enables higher surge repetition rates | Choose for high-duty-cycle surge environments (e.g., starter motor control) where SMA thermal limits are exceeded. |
Compared with SMA6T68AY, SMA6T68CAY offers polarity-agnostic protection critical for differential buses; compared with SMC6T68CAY, it trades thermal robustness for space-constrained PCB layouts - ideal for compact automotive modules where board area is prioritized over extreme surge repetition.
Availability
SMA6T68CAY is available at Aetrix Electronics and suitable for automotive body electronics, infotainment power management, and CAN FD interface protection requiring stable component supply across multi-year vehicle production cycles.
Supply support for SMA6T68CAY 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 AEC-Q100/101 validation infrastructure.
SMA6T68CAY belongs to the SMA6TY Transil series - engineered specifically for automotive-grade transient suppression in 12 V systems, with emphasis on ISO 7637-2 and ISO 10605 compliance, high-temperature reliability, and planar process consistency.
FAQ
Is SMA6T68CAY suitable for 24 V commercial vehicle applications?
No - its 68 V breakdown voltage and 92 V clamping are optimized for 12 V automotive systems. For 24 V platforms, ST recommends SMA6T130CAY (VBR = 130 V min) or SMC6T130CAY to maintain adequate margin above 28 V nominal and 35 V load dump peaks.
What is the maximum recommended PCB copper area for optimal thermal performance?
ST specifies 1 cm² total copper area (0.5 cm² per pad) on FR4 with 70 µm Cu thickness for rated 600 W pulse handling. Increasing copper to 2 cm² reduces Rth(j-a) from 55 °C/W to ~40 °C/W, enabling higher surge repetition rates without junction overheating.
Does SMA6T68CAY require derating at elevated ambient temperatures?
Yes - peak pulse power drops linearly with junction temperature: at Tj = 125 °C, PPP is reduced to ~70% of 600 W (≈420 W) per Figure 3. Designers must ensure thermal design keeps Tj ≤125 °C during worst-case surge repetition to avoid permanent parametric shift.
Can SMA6T68CAY be used in parallel for higher surge current handling?
No - TVS diodes exhibit negative temperature coefficient and mismatched VBR tolerances (±5%), causing current hogging and premature failure. For >6.5 A 10/1000 µs requirements, select higher-power packages like SMC6T68CAY or SMA6T68CAY in validated multi-device layouts per ST AN4277.
SMA6T68CAY 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:
- -
- Bidirectional Channels:
- 1
- 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)
SMA6T68CAY FAQ
1.How can I place an order for SMA6T68CAY through Aetrix?
Please submit a Request for Quotation (RFQ) for SMA6T68CAY 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 SMA6T68CAY reliable?
The price and inventory of SMA6T68CAY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMA6T68CAY is usually 5 days.
3.What payment methods are accepted for SMA6T68CAY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMA6T68CAY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMA6T68CAY?
SMA6T68CAY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMA6T68CAY 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 SMA6T68CAY?
For technical support, including SMA6T68CAY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMA6T68CAY requirements.
6.How does Aetrix verify that SMA6T68CAY is sourced from the original manufacturer or authorized distributors?
All SMA6T68CAY 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 SMA6T68CAY meets industry standards.
7.What is the process for return or replacement of SMA6T68CAY?
All SMA6T68CAY units undergo pre-shipment inspection (PSI). If there is an issue with SMA6T68CAY, 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 SMA6T68CAY part is unused and in its original packaging.
Return procedure for SMA6T68CAY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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