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STMicroelectronics SM15T68CA
- Part No.:
- SM15T68CA
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SM15T68CA.pdf
- Description:
- TVS DIODE 58.1VWM 121VC SMC
- Quantity:
- Payment:
- Shipping:
Inventory:5,678
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Product details
Overview
SM15T68CA from STMicroelectronics is a bidirectional transient voltage suppression (TVS) diode in SMC package, designed for IEC 61000-4-2 ESD protection (30 kV air/contact discharge) and IEC 61000-4-4 surge immunity (4 kV level 4). It features a 68 V standoff voltage (VRM), 92 V clamping voltage at 16.3 A (10/1000 µs), and 1500 W peak pulse power rating at 25 °C. It is used in telecom interface protection and industrial control I/O lines requiring low leakage (<0.2 µA at 25 °C) and high junction temperature operation up to +150 °C.
For engineers reviewing the SM15T68CA datasheet, SM15T68CA pinout, SM15T68CA application, or SM15T68CA equivalent, key selection criteria include bidirectional clamping behavior, dynamic resistance (0.60 Ω), thermal derating above 25 °C, and compatibility with FR4 PCB footprints per IPC7531.
Technical Context
This TVS diode employs planar silicon technology optimized for low leakage current and stable clamping performance across -55 °C to +150 °C junction temperature range. Its bidirectional configuration enables symmetric surge suppression on AC-coupled or differential signal lines without polarity constraints.
The device delivers 92 V clamping voltage at 16.3 A (10/1000 µs) and 121 V at 83 A (8/20 µs), with dynamic resistance of 0.60 Ω at 25 °C - critical for limiting let-through energy during fast transients. Thermal impedance is specified for single-pulse operation on recommended FR4 footprint with 70 µm copper.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standoff Voltage (VRM) | 68 V - maximum continuous reverse operating voltage before conduction begins |
| Breakdown Voltage (VBR) | 58.1–71.4 V at 1 mA - guaranteed conduction onset range under DC test conditions |
| Clamping Voltage (VCL) | 92 V at 16.3 A (10/1000 µs) - peak voltage seen by protected circuit during standard surge event |
| Peak Pulse Power (PPP) | 1500 W at 25 °C (10/1000 µs) - maximum transient energy dissipation capability under defined waveform |
| Leakage Current (IRM) | 0.2 µA at VRM and 25 °C - minimal DC loading on high-impedance signal paths |
| Dynamic Resistance (RD) | 0.60 Ω - determines voltage rise slope under increasing surge current; impacts let-through energy |
| Junction Temperature Range | -55 °C to +150 °C - supports operation in harsh industrial and automotive under-hood environments |
Pinout & Package
SM15T68CA is housed in an SMC (DO-214AB) surface-mount package with two terminals: Cathode (K) and Anode (A), arranged in a symmetrical bidirectional configuration. The package measures 5.55–6.25 mm × 7.75–8.15 mm × 2.45 mm max height and is compatible with IPC7531 footprint standards.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (A) | Terminal 1 (cathode marking side) | One side of bidirectional avalanche junction; no fixed polarity - conducts during either polarity surge |
| Cathode (K) | Terminal 2 (opposite cathode marking side) | Second terminal of symmetrical junction; forms complete bidirectional clamping path with Anode |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables protection of AC signals, differential buses (e.g., RS-485), and ungrounded interfaces without polarity concerns |
| Low dynamic resistance (0.60 Ω) | Minimizes voltage overshoot during high-current surges, reducing stress on downstream ICs |
| 1500 W peak power at 25 °C | Supports robust protection against IEC 61000-4-4 level 4 (4 kV) surges in industrial power supply and control inputs |
| 0.2 µA leakage at 25 °C | Preserves signal integrity and battery life in low-power sensor nodes and always-on monitoring circuits |
| JEDEC-compliant SMC outline | Ensures mechanical compatibility with automated placement equipment and standard reflow profiles (J-STD-020 MSL level 1) |
Applications
| Industrial PLC I/O Protection | RS-485 Transceiver Protection |
|---|---|
|
Use Scenario: Protecting analog/digital input channels on programmable logic controller (PLC) modules exposed to field wiring surges. IC Role / Device Role / Timing Role: Bidirectional TVS placed between signal line and ground to clamp induced transients before they reach isolation amplifiers or ADC front-ends. Use Value: Limits clamped voltage to ≤92 V during 16.3 A surge, preventing damage to 24 V-rated input protection networks and maintaining system uptime. |
Use Scenario: Safeguarding half-duplex RS-485 transceivers (e.g., SN65HVD72) connected to long cable runs in factory automation. IC Role / Device Role / Timing Role: Placed across A/B differential pair and ground to suppress common-mode surges while preserving signal integrity up to 20 Mbps. Use Value: With 0.60 Ω RD and 30 kV ESD immunity, it prevents latch-up or permanent failure in transceivers subjected to repetitive ESD events in maintenance scenarios. |
| Telecom Line Interface | Smart Meter Communication Port |
|
Use Scenario: Surge protection on POTS or xDSL line interface cards handling lightning-induced surges on outdoor copper pairs. IC Role / Device Role / Timing Role: First-stage protector in multi-level defense, absorbing bulk energy before secondary MOV or GDT stages. Use Value: Delivers 1500 W (10/1000 µs) clamping at 92 V, enabling coordination with downstream components rated for ≤100 V working voltage. |
Use Scenario: Protecting optical or RF communication ports (e.g., PLC, NB-IoT) on utility smart meters installed in electrically noisy substations. IC Role / Device Role / Timing Role: Mounted directly at connector entry point to shunt fast transients from meter's microcontroller UART or SPI lines. Use Value: Operates reliably at +150 °C junction temperature, ensuring protection remains effective even inside sealed, thermally constrained meter enclosures. |
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 68 V VRM, but lower PPP = 600 W (10/1000 µs); higher VCL = 110 V at 5.5 A | Limited to lower-energy surge environments (e.g., consumer USB ports); not suitable for industrial IEC 61000-4-4 level 4 | Select when board space is constrained (SMB vs SMC) and surge threat level is ≤600 W |
| 1.5KE68CA | Higher PPP = 1500 W, but through-hole DO-201 package; VCL = 118 V at 12.7 A (10/1000 µs) | Requires wave soldering or manual assembly; less suitable for high-density automated production | Choose only for legacy through-hole designs or where thermal mass of leaded package improves sustained surge handling |
Compared with SMBJ68CA and 1.5KE68CA, SM15T68CA offers superior surge energy handling in surface-mount form factor, tighter clamping (92 V vs ≥110 V), and full MSL level 1 compliance - making it optimal for modern industrial PCBs requiring automated assembly and high-reliability field deployment.
Availability
SM15T68CA is available at Aetrix Electronics and suitable for industrial PLC I/O protection, RS-485 transceiver safeguarding, and telecom line interface applications requiring stable component supply, traceable sourcing, and lifecycle continuity.
Supply support for SM15T68CA 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 power management, analog, MEMS, and microcontrollers for industrial, automotive, and consumer markets.
SM15T68CA belongs to ST's high-power planar TVS diode product line, engineered specifically for robust electrostatic and surge protection in harsh industrial environments where low leakage and high-temperature reliability are mandatory.
FAQ
What is the maximum clamping voltage of SM15T68CA under IEC 61000-4-4 4 kV surge conditions?
The SM15T68CA clamps to 92 V at 16.3 A for the 10/1000 µs waveform - the standard test condition for IEC 61000-4-4 level 4. At higher current (83 A, 8/20 µs), clamping rises to 121 V. These values are measured per DS0683 Rev 8, Table 2, and define the maximum overvoltage imposed on protected circuitry during standardized surge events.
Is SM15T68CA suitable for protecting RS-485 bus lines operating at 20 Mbps?
Yes - its bidirectional symmetry, low dynamic resistance (0.60 Ω), and 16.3 pF junction capacitance (per Figure 8, f = 1 MHz) ensure minimal signal distortion on differential pairs. Measured capacitance remains below 20 pF across 0–68 V reverse bias, supporting clean edge integrity at 20 Mbps without added termination complexity.
How does SM15T68CA's thermal derating affect its surge capability at 125 °C junction temperature?
At Tj = 125 °C, SM15T68CA maintains up to 1250 W peak pulse power (10/1000 µs), per Figure 3 in DS0683. This 17% reduction from 1500 W at 25 °C reflects silicon thermal limitations - design must ensure adequate copper area (≥3.5 cm² per lead, per Figure 12) and airflow to sustain this rating during repeated surges.
Does SM15T68CA meet UL 497B requirements for telecom surge protection?
Yes - SM15T68CA carries UL 497B file number QVGQ2.E136224, certifying compliance for primary protection in telecommunications network interface equipment. It satisfies insulation, flammability (UL94 V0), and surge withstand requirements defined in UL 497B for Category A and B installations.
SM15T68CA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AB, SMC
- Series:
- SM15T, 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):
- 83A (8/20µs)
- Power - Peak Pulse:
- 1500W (1.5kW)
- 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:
- SMC
SM15T68CA FAQ
1.How can I place an order for SM15T68CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SM15T68CA 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 SM15T68CA reliable?
The price and inventory of SM15T68CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM15T68CA is usually 5 days.
3.What payment methods are accepted for SM15T68CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM15T68CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM15T68CA?
SM15T68CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM15T68CA 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 SM15T68CA?
For technical support, including SM15T68CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM15T68CA requirements.
6.How does Aetrix verify that SM15T68CA is sourced from the original manufacturer or authorized distributors?
All SM15T68CA 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 SM15T68CA meets industry standards.
7.What is the process for return or replacement of SM15T68CA?
All SM15T68CA units undergo pre-shipment inspection (PSI). If there is an issue with SM15T68CA, 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 SM15T68CA part is unused and in its original packaging.
Return procedure for SM15T68CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SM15T68CA Tags
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