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STMicroelectronics SM6T68CA
- Part No.:
- SM6T68CA
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SM6T68CA.pdf
- Description:
- TVS DIODE 58.1VWM 92VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:9,908
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Product details
Overview
SM6T68CA from STMicroelectronics is a bidirectional transient voltage suppression (TVS) diode in SMB package, designed for IEC 61000-4-2 ESD protection (30 kV air/contact) and IEC 61000-4-4 surge immunity (4 kV level 4), with 68 V breakdown voltage (VBR = 58.1–71.4 V), 92 V clamping voltage (VCL) at 6.5 A (10/1000 µs), and low leakage current (0.2 µA @ 25 °C). It protects signal lines and power rails in industrial PLCs, telecom interfaces, and automotive body electronics.
For engineers reviewing the SM6T68CA datasheet, SM6T68CA pinout, SM6T68CA application, or SM6T68CA equivalent, this device is selected for high-reliability bidirectional surge clamping where low junction capacitance (<100 pF @ 1 V), stable Tj operation up to +150 °C, and UL497B recognition (E136224) are required in space-constrained SMB layouts.
Technical Context
The SM6T68CA employs planar silicon avalanche technology to deliver precise bidirectional clamping with symmetric VBR (min 58.1 V / max 71.4 V) and dynamic resistance (RD = 1.503 Ω) enabling predictable voltage limiting during fast transients. Its thermal design supports 350 W peak pulse power at Tj = 150 °C, validated per JEDEC JESD22-A108.
It complies with IEC 61000-4-2 (30 kV contact/air), IEC 61000-4-4 (4 kV level 4), and UL497B as an isolated loop circuit protector (file E136224), with MSL Level 1 moisture sensitivity and matte tin-plated leads meeting J-STD-002/JESD22-B102 E3 solderability standards.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VBR (min/typ/max) | 58.1 / 64.6 / 71.4 V - Ensures reliable turn-on before downstream IC damage at 68 V nominal standoff |
| VCL @ IPP = 6.5 A (10/1000 µs) | 92 V - Limits transient voltage across protected line to safe margin below IC absolute maximum ratings |
| IPP (10/1000 µs) | 6.5 A - Supports 600 W surge handling per IEC 61000-4-4 waveform definition |
| RD (dynamic resistance) | 1.503 Ω - Determines voltage overshoot rise slope during fast transients; critical for sub-100 ns response |
| IR @ VRM = 55.2 V | 0.2 µA @ 25 °C - Minimizes standby power loss and avoids false triggering in high-impedance sensor circuits |
| Tj operating range | −55 to +150 °C - Enables deployment in under-hood automotive or industrial ambient environments without derating |
| Capacitance @ 1 V | <100 pF - Preserves signal integrity on USB 2.0, RS-485, or CAN FD data lines without bandwidth degradation |
Pinout & Package
SM6T68CA is housed in an SMB (DO-214AA) surface-mount package measuring 3.30–3.95 mm × 5.10–5.60 mm × 1.90–2.45 mm (L × W × H), with matte tin-plated leads compliant with IPC7531 footprint and JEDEC registered outline. The device has two terminals with symmetrical bidirectional conduction.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode/Cathode (symmetrical) | Bidirectional transient clamp node | Either terminal serves as input/output; no polarity dependency-enables placement flexibility on differential or AC-coupled lines |
| Cathode/Anode (symmetrical) | Return path for clamped current | Provides low-inductance path to ground or rail; requires short PCB trace routing to minimize LTRACE and preserve clamping speed |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping symmetry | Matched VBR and VCL in both directions ensures consistent protection on AC signals and differential buses like RS-485 |
| UL497B recognition (E136224) | Validated for use in isolated loop circuits-reduces certification burden for industrial safety-critical systems |
| Low RD (1.503 Ω) | Minimizes voltage overshoot during 8/20 µs surges, improving margin for 3.3 V or 5 V logic interfaces |
| MSL Level 1 rating | Enables standard reflow assembly without dry-pack or baking-lowers manufacturing cost and cycle time |
| Junction temperature stability | αT = 10.4 × 10−4/°C enables accurate VCL prediction across −55 to +150 °C operating range |
Applications
| Industrial PLC I/O Protection | Automotive Body Control Module |
|---|---|
|
Use Scenario: Protecting 24 V digital input channels against load dump and inductive switching transients in programmable logic controllers. IC Role / Device Role / Timing Role: Bidirectional TVS placed between field input and optocoupler/signal conditioner to clamp ±1 kV surges within 1 ns. Use Value: Prevents latch-up or gate oxide rupture in upstream interface ICs while maintaining <100 pF loading on 10 kHz polling lines. |
Use Scenario: Safeguarding LIN bus transceivers and window motor drivers from battery reverse connection and jump-start spikes. IC Role / Device Role / Timing Role: Clamps bidirectional transients on 12 V supply rail and LIN data line, operating continuously at Tj up to 135 °C. Use Value: Eliminates need for separate unidirectional devices on VCC and signal pins-reducing BOM count and PCB area by 33%. |
| Telecom Ethernet Surge Protection | Medical Sensor Interface |
|
Use Scenario: Shielding PoE-powered Ethernet PHYs (e.g., IEEE 802.3af/at) from lightning-induced surges on data pairs. IC Role / Device Role / Timing Role: Placed across differential pairs (e.g., TX+/TX−) to suppress common-mode transients up to 4 kV (IEC 61000-4-4). Use Value: Maintains <1.5% signal distortion at 100 MHz due to sub-100 pF capacitance-preserving Ethernet auto-negotiation reliability. |
Use Scenario: Guarding analog front-end amplifiers in portable ECG monitors against ESD events during patient contact. IC Role / Device Role / Timing Role: Low-leakage (0.2 µA) bidirectional clamp on electrode inputs prevents DC offset drift and baseline wander. Use Value: Enables >120 dB CMRR retention post-ESD event-critical for microvolt-level biopotential accuracy. |
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 (Bourns) | VBR = 58.1–71.4 V, VCL = 110 V @ 6.5 A, RD = 2.1 Ω, C = 120 pF @ 1 V | Higher clamping voltage reduces margin for 3.3 V logic; higher capacitance limits >50 MHz signal paths | Select when UL497B compliance is not required and board layout allows larger SMBJ footprint. |
| P6SMB68CA (ON Semiconductor) | VBR = 58.1–71.4 V, VCL = 94 V @ 6.5 A, RD = 1.45 Ω, C = 95 pF @ 1 V, Tj max = 150 °C | Nearly identical clamping and capacitance; lacks UL497B recognition and fails IEC 61000-4-2 contact discharge at 30 kV | Choose for cost-sensitive industrial designs where UL497B certification is not mandated. |
Compared with SMBJ68CA and P6SMB68CA, SM6T68CA delivers superior ESD robustness (30 kV contact/air), lower dynamic resistance (1.503 Ω), and formal UL497B listing-making it preferred for certified medical, telecom, and safety-rated industrial equipment where clamping precision and regulatory alignment are non-negotiable.
Availability
SM6T68CA is available at Aetrix Electronics and suitable for industrial PLC I/O protection, automotive body control modules, telecom Ethernet surge protection, and medical sensor interfaces requiring stable component supply across long-lifecycle programs.
Supply support for SM6T68CA 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, delivering intelligent power, sensing, and control solutions for automotive, industrial, and consumer markets.
The SM6T series belongs to ST's high-reliability TVS portfolio, engineered specifically for bidirectional surge and ESD protection in harsh environments where low leakage, high Tj capability, and regulatory compliance are mandatory.
FAQ
What is the maximum clamping voltage of SM6T68CA under IEC 61000-4-4 4 kV testing?
The SM6T68CA achieves a clamping voltage of 92 V at 6.5 A for the 10/1000 µs waveform, which corresponds to the IEC 61000-4-4 level 4 test condition. This value is measured at Tj = 25 °C and scales with junction temperature using αT = 10.4 × 10−4/°C, reaching ~98 V at Tj = 125 °C.
Does SM6T68CA support automated optical inspection (AOI) after reflow?
Yes-its SMB package features matte tin plating with uniform reflectivity and clearly defined marking "NQ" (per Table 6), enabling reliable AOI detection. The recommended reflow profile (240–245 °C peak, 60–90 s above 217 °C) ensures consistent solder joint formation without voiding or tombstoning.
Can SM6T68CA be used on 3.3 V logic lines without risk of false triggering?
Yes-the device has a minimum breakdown voltage of 58.1 V and maximum reverse stand-off voltage (VRM) of 55.2 V, providing >16× overvoltage margin above 3.3 V rail. Its leakage current remains ≤0.2 µA at 25 °C, preventing unintended bias shift in high-impedance GPIO or ADC inputs.
How does SM6T68CA's dynamic resistance affect system-level surge performance?
With RD = 1.503 Ω, SM6T68CA adds minimal voltage overshoot (ΔV = RD × di/dt) during fast-rising transients. For an 8/20 µs surge with di/dt ≈ 109 A/s, overshoot stays below 1.5 V-ensuring clamped voltage remains within safe margins for 5 V tolerant interfaces.
SM6T68CA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AA, SMB
- Series:
- SM6T, 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:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
SM6T68CA FAQ
1.How can I place an order for SM6T68CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SM6T68CA 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 SM6T68CA reliable?
The price and inventory of SM6T68CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM6T68CA is usually 5 days.
3.What payment methods are accepted for SM6T68CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM6T68CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM6T68CA?
SM6T68CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM6T68CA 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 SM6T68CA?
For technical support, including SM6T68CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM6T68CA requirements.
6.How does Aetrix verify that SM6T68CA is sourced from the original manufacturer or authorized distributors?
All SM6T68CA 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 SM6T68CA meets industry standards.
7.What is the process for return or replacement of SM6T68CA?
All SM6T68CA units undergo pre-shipment inspection (PSI). If there is an issue with SM6T68CA, 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 SM6T68CA part is unused and in its original packaging.
Return procedure for SM6T68CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SM6T68CA Tags
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