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STMicroelectronics SM6T39CA
- Part No.:
- SM6T39CA
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SM6T39CA.pdf
- Description:
- TVS DIODE 33.3VWM 53.9VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:11,756
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Product details
Overview
SM6T39CA from STMicroelectronics is a bidirectional transient voltage suppression (TVS) diode designed for robust ESD and surge protection on signal/power lines in industrial, telecom, and automotive electronics. It delivers 600 W peak pulse power (10/1000 µs), clamps transients to 53.9 V at 11.1 A, and operates up to 150 °C junction temperature - enabling reliable protection in high-temperature SMPS and interface circuits.
For engineers reviewing the SM6T39CA datasheet, SM6T39CA pinout, SM6T39CA application, or SM6T39CA equivalent, key selection criteria include its bidirectional 39 V breakdown voltage (VBR = 33.3–41.0 V), low leakage (<0.2 µA @ 25 °C), IEC 61000-4-2 ±30 kV contact/air discharge compliance, and SMB package thermal performance under sustained surge stress.
Technical Context
The SM6T39CA employs planar silicon junction technology optimized for low leakage and stable clamping across –55 °C to +150 °C operating range. Its bidirectional structure provides symmetrical protection against both positive and negative transients without polarity dependence.
Clamping behavior is defined by dynamic resistance (RD = 1.16 Ω at 8/20 µs), enabling precise VCL = VBR(max) + RD × IPP calculation. It meets UL497B recognition (E136224) as an isolated loop circuit protector and exceeds IEC 61000-4-4 Level 4 (4 kV) and IEC 61000-4-2 Level 4 (±30 kV).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VBR (min/typ/max) | 33.3 V / 37.1 V / 41.0 V - ensures reliable turn-on before downstream IC damage threshold |
| VCL @ IPP = 11.1 A | 53.9 V - maximum clamped voltage during 10/1000 µs surge, limiting stress on protected circuitry |
| PPP (10/1000 µs) | 600 W - sustains repetitive surges in industrial control I/O without degradation |
| IR @ VRM = 33.3 V | 0.2 µA @ 25 °C - minimizes standby power loss and signal integrity impact in high-impedance lines |
| Tj max | +150 °C - supports operation in enclosed enclosures or near heat-generating components |
| Package | SMB (DO-214AA) - industry-standard surface-mount footprint with IPC7531-compliant pad layout |
| ESD Rating | ±30 kV (IEC 61000-4-2, contact & air) - exceeds Level 4 for direct human interaction points |
Pinout & Package
SMB (DO-214AA) package: 2-terminal surface-mount device with cathode band marking; dimensions per JEDEC MS-012 (A1 = 1.90–2.45 mm, D = 3.30–3.95 mm, E = 5.10–5.60 mm); matte tin-plated leads compliant with J-STD-002 E3 and MIL-STD-750 Method 2026.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (unmarked end) | Transient current sink (bidirectional) | Conducts during negative transients; symmetric with cathode for full-cycle protection |
| Cathode (banded end) | Transient current sink (bidirectional) | Conducts during positive transients; identical clamping behavior to anode due to bidirectional design |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping symmetry | Identical VBR and VCL for ± polarity - eliminates need for polarity-aware layout in differential or AC-coupled lines |
| Low dynamic resistance | RD = 1.16 Ω (8/20 µs) - reduces clamping voltage rise under high-current surges, improving protection margin |
| High-temperature reliability | Rated Tj = 150 °C with <0.2 µA leakage at 25 °C - enables stable operation in thermally constrained SMPS feedback paths |
| UL497B recognition | Agency file E136224 - validates suitability for isolated loop protection in telecom and industrial safety-critical interfaces |
| Robust solderability | J-STD-020 MSL Level 1, 260 °C lead temperature - supports standard reflow without moisture sensitivity concerns |
Applications
| Industrial PLC I/O Protection | Automotive Body Control Module (BCM) Inputs |
|---|---|
|
Use Scenario: Protecting 24 V digital input channels in programmable logic controllers against inductive switching spikes and ESD events from field wiring. IC Role / Device Role / Timing Role: Bidirectional TVS clamp placed between signal line and ground, absorbing >4 kV IEC 61000-4-4 transients before reaching optocoupler or microcontroller GPIO. Use Value: Prevents latch-up or permanent damage to isolation barriers and input comparators while maintaining <0.2 µA leakage to avoid false triggering. |
Use Scenario: Safeguarding LIN bus and sensor inputs (e.g., door lock switches, ambient light sensors) in automotive BCMs exposed to load dump and human ESD. IC Role / Device Role / Timing Role: Primary surge suppressor on unidirectional/bidirectional signal lines, operating within –40 °C to +125 °C ambient with validated UL497B compliance. Use Value: Enables single-device protection for both polarities without external polarity logic, reducing BOM count and PCB area in space-constrained modules. |
| Telecom Line Interface Circuits | AC/DC Power Supply Feedback Loops |
|
Use Scenario: Shielding RS-485 transceivers and Ethernet PHYs in outdoor telecom cabinets from lightning-induced surges and cable discharge events. IC Role / Device Role / Timing Role: First-line transient suppressor on differential pairs, clamping to ≤53.9 V within nanoseconds to prevent transceiver latch-up or burnout. Use Value: Meets IEC 61000-4-5 (surge) and IEC 61000-4-2 (ESD) requirements simultaneously with minimal capacitance impact on signal integrity. |
Use Scenario: Protecting optocoupler feedback paths in isolated AC/DC adapters and server PSUs where high junction temperature and low leakage are critical. IC Role / Device Role / Timing Role: Voltage-clamping element across secondary-side error amplifier inputs, ensuring stable regulation during output overvoltage or startup transients. Use Value: Maintains <0.2 µA leakage at 25 °C and <1 µA at 85 °C - avoids bias current errors that degrade output voltage accuracy over temperature. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ39CA (Littelfuse) | VBR = 34.2–37.8 V; VCL = 56.4 V @ 10.6 A; PPP = 400 W (10/1000 µs) | Lower peak power rating limits use in high-energy industrial surges | Select when cost sensitivity outweighs need for 600 W surge handling |
| P6SMB39CA (ON Semiconductor) | VBR = 33.2–36.8 V; VCL = 53.3 V @ 11.3 A; same SMB package | Nearly identical clamping but slightly lower VBR min and no UL497B recognition | Choose for drop-in replacement where agency certification is not required |
Compared with SMAJ39CA and P6SMB39CA, SM6T39CA offers higher peak pulse power (600 W vs. 400 W/600 W), tighter VBR tolerance (±10% vs. ±10%/±10%), and UL497B recognition - making it preferred for safety-critical isolated loop designs requiring certified surge immunity.
Availability
SM6T39CA is available at Aetrix Electronics and suitable for industrial PLC I/O protection, automotive body control module inputs, and telecom line interface circuits requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for SM6T39CA 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.
The SM6T series belongs to ST's transient protection portfolio, engineered specifically for high-reliability ESD/surge suppression in harsh environments - emphasizing low leakage, high-temperature stability, and regulatory compliance for mission-critical interfaces.
FAQ
What is the difference between SM6T39A and SM6T39CA?
SM6T39A is unidirectional (anode-cathode asymmetry), conducting only in reverse bias, while SM6T39CA is bidirectional - electrically symmetric with identical clamping for both positive and negative transients. The 'CA' suffix explicitly denotes bidirectional functionality, verified in Table 2 of DS0684 Rev 15.
Does SM6T39CA meet automotive AEC-Q200 requirements?
No - SM6T39CA is not AEC-Q200 qualified. It is rated for industrial and telecom applications with Tj = –55 °C to +150 °C and UL497B recognition, but lacks the stress testing, failure analysis, and qualification documentation required for automotive-grade components.
Can SM6T39CA be used in parallel for higher surge current handling?
Not recommended without derating and matching. Parallel connection introduces imbalance due to VBR tolerance (±10%) and thermal coupling differences, risking current hogging. For >11.1 A surge currents, select a higher-rated device like SM8T39CA (1500 W) instead.
What is the thermal resistance (Rth(j-a)) of SM6T39CA on a standard FR4 PCB?
Per Figure 12 in DS0684 Rev 15, Rth(j-a) = ~120 °C/W with 1 cm² copper area per lead, dropping to ~80 °C/W with 2.5 cm². This enables sustained 350 W dissipation at Tj = 150 °C when mounted on recommended IPC7531 footprint with adequate copper pour.
SM6T39CA 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):
- 33.3V
- Voltage - Breakdown (Min):
- 37.1V
- Voltage - Clamping (Max) @ Ipp:
- 53.9V
- Current - Peak Pulse (10/1000µs):
- 11.1A
- 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
SM6T39CA FAQ
1.How can I place an order for SM6T39CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SM6T39CA 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 SM6T39CA reliable?
The price and inventory of SM6T39CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM6T39CA is usually 5 days.
3.What payment methods are accepted for SM6T39CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM6T39CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM6T39CA?
SM6T39CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM6T39CA 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 SM6T39CA?
For technical support, including SM6T39CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM6T39CA requirements.
6.How does Aetrix verify that SM6T39CA is sourced from the original manufacturer or authorized distributors?
All SM6T39CA 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 SM6T39CA meets industry standards.
7.What is the process for return or replacement of SM6T39CA?
All SM6T39CA units undergo pre-shipment inspection (PSI). If there is an issue with SM6T39CA, 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 SM6T39CA part is unused and in its original packaging.
Return procedure for SM6T39CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SM6T39CA Tags
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onsemi
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Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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Nexperia USA Inc.
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Toshiba Semiconductor and Storage
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Diodes Incorporated
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