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STMicroelectronics SM6T39CAY
- Part No.:
- SM6T39CAY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SM6T39CAY.pdf
- Description:
- TVS DIODE 33.3VWM 53.9VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:9,721
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Product details
Overview
SM6T39CAY from STMicroelectronics is a bidirectional automotive-grade transient voltage suppression (TVS) diode in SMB package, designed for ISO 7637-2 pulse protection and IEC 61000-4-2 ESD immunity. It features a 39 V standoff voltage (VRM), 53.9 V clamping voltage at 11.1 A (10/1000 µs), 600 W peak pulse power, and operates up to 150 °C junction temperature - deployed in 12 V automotive power line protection.
For engineers reviewing the SM6T39CAY datasheet, SM6T39CAY pinout, SM6T39CAY application, or SM6T39CAY equivalent, key selection criteria include bidirectional surge clamping performance under ISO 7637-2 Pulse 1/2a/3a/3b, low leakage (<0.2 µA @ 25 °C), thermal stability at Tj = 150 °C, and compliance with AEC-Q101 and ISO10605 ±30 kV (air/contact discharge).
Technical Context
This device uses planar silicon technology to achieve low leakage current and high thermal robustness, enabling stable operation across -55 °C to +150 °C junction range. Its bidirectional structure provides symmetrical clamping for both positive and negative transients without polarity dependency.
The SM6T39CAY meets stringent automotive EMC requirements: ISO 7637-2 Pulse 1 (-150 V), Pulse 2a (+112 V), Pulse 3a (-220 V), and Pulse 3b (+150 V); it also exceeds IEC 61000-4-2 Level 4 (±30 kV air/contact) and ISO 10605 (C = 150 pF/R = 330 Ω and C = 330 pF/R = 330 Ω).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standoff Voltage (VRM) | 39 V - Maximum continuous reverse operating voltage before breakdown; defines circuit operating margin against normal battery fluctuations. |
| Breakdown Voltage (VBR) | 33.3–41.0 V @ IBR = 1 mA - Voltage at which device enters avalanche conduction; ensures reliable triggering during surges. |
| Clamping Voltage (VCL) | 53.9 V @ IPP = 11.1 A (10/1000 µs) - Peak voltage seen by protected circuit during worst-case surge; limits stress on downstream ICs. |
| Peak Pulse Power (PPP) | 600 W @ 10/1000 µs - Sustained energy-handling capability at ambient; derates to 515 W at Tj = 150 °C per Figure 3. |
| Leakage Current (IRM) | 0.2 µA @ 25 °C, 1 µA @ 85 °C - Minimal DC loading on signal/power lines; critical for low-power sensor interfaces. |
| Junction Temperature Range | -55 °C to +150 °C - Enables under-hood deployment in engine control units and body electronics without thermal derating penalties. |
| ESD Withstand | ±30 kV (IEC 61000-4-2, C = 150 pF/R = 330 Ω; ISO 10605, C = 330 pF/R = 330 Ω) - Full compliance with automotive ESD immunity standards. |
Pinout & Package
SM6T39CAY is housed in an SMB (DO-214AA) surface-mount package with two terminals: Cathode (K) and Anode (A). The bidirectional configuration means both terminals are functionally symmetric - no polarity marking required for mounting orientation in AC-coupled or floating bus applications.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (A) | Transient return path (bidirectional) | Provides low-impedance path to ground or reference during either polarity surge; interchangeable with cathode in layout. |
| Cathode (K) | Transient return path (bidirectional) | Functions identically to anode under reverse surge; enables symmetrical clamping without directional routing constraints. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive use including temperature cycling, humidity, and mechanical shock - required for ECUs, ADAS, and infotainment modules. |
| Bidirectional clamping | Enables single-device protection of differential buses (e.g., LIN, CAN FD stubs) or ungrounded power rails without polarity concerns. |
| Low dynamic resistance (RD) | 0.504 Ω - Minimizes clamping voltage rise under high-current pulses, improving protection margin for sensitive microcontrollers. |
| High-temperature reliability | Rated for 150 °C junction operation with <0.2 µA leakage at 25 °C - supports long-term stability in engine bay and power distribution units. |
| Automotive footprint compliance | IPC7531-compliant SMB outline with JEDEC registered dimensions - ensures compatibility with standard SMT assembly and reflow profiles (J-STD-020 MSL 1). |
Applications
| Engine Control Unit (ECU) Power Input | Body Control Module (BCM) LIN Bus |
|---|---|
|
Use Scenario: Protects 12 V supply rail of engine control units against load dump, jump-start, and alternator ripple. IC Role / Device Role / Timing Role: Bidirectional TVS clamps both negative (Pulse 1, -150 V) and positive (Pulse 2a, +112 V) transients on main power input. Use Value: Prevents latch-up or permanent damage to MCU power regulators and CAN transceivers during ISO 7637-2 events. |
Use Scenario: Shields LIN physical layer transceivers from ESD and coupled noise in door modules and seat controllers. IC Role / Device Role / Timing Role: Clamps ±30 kV ESD strikes (ISO 10605) and fast transients (IEC 61000-4-4) on LIN data line. Use Value: Maintains communication integrity without adding series resistance or capacitance that would distort LIN timing. |
| ADAS Camera Power Supply | Infotainment USB Interface |
|
Use Scenario: Guards 5 V/3.3 V camera module power inputs against hot-swap and cable discharge events in front/rear cameras. IC Role / Device Role / Timing Role: Limits voltage excursion to ≤53.9 V during 11.1 A surge, preserving image sensor and ISP power integrity. Use Value: Eliminates need for secondary filtering or redundant LDOs while meeting ASIL-B functional safety margins. |
Use Scenario: Protects USB 2.0 VBUS and D+/D− lines in head unit against ESD and docking surges. IC Role / Device Role / Timing Role: Bidirectional clamping handles both VBUS overvoltage and data-line ESD without polarity biasing. Use Value: Achieves full USB-IF ESD compliance (±15 kV contact) with one device per line, reducing BOM count vs. unidirectional solutions. |
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 | Same SMB package, 39 V VRM, but lower PPP = 400 W (10/1000 µs); higher VCL = 60.0 V @ 6.7 A. | Limited to non-critical 12 V circuits where ISO 7637-2 Pulse 3a (-220 V) margin is relaxed. | Select when cost sensitivity outweighs peak surge margin; verify clamping voltage does not exceed downstream IC absolute max ratings. |
| 1.5KE39CA | DO-201 package, 39 V VRM, 1500 W PPP (10/1000 µs), but leaded through-hole; not AEC-Q101 qualified. | Restricted to non-automotive industrial or prototyping use due to package and qualification gap. | Use only for bench validation or legacy board upgrades where SMB footprint and automotive qualification are not required. |
Compared with SMAJ39CA and 1.5KE39CA, SM6T39CAY delivers superior automotive compliance (AEC-Q101, ISO 7637-2, ISO 10605), tighter clamping (53.9 V vs. 60.0 V), and optimized SMB footprint for high-density automotive PCBs - making it the preferred choice for production ECU and ADAS designs.
Availability
SM6T39CAY is available at Aetrix Electronics and suitable for engine control units, body control modules, ADAS camera systems, and infotainment USB interfaces requiring stable component supply with full automotive qualification traceability.
Supply support for SM6T39CAY 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 technologies with broad IP portfolio and manufacturing scale.
The SM6TY series belongs to ST's automotive-grade Transil™ TVS portfolio, engineered specifically for robust transient protection in harsh vehicle environments - targeting ISO 7637-2, ISO 10605, and AEC-Q101 compliance without performance trade-offs.
FAQ
Is SM6T39CAY suitable for CAN bus line protection?
No - SM6T39CAY is not recommended for direct CAN H/L line protection due to its 53.9 V clamping voltage, which exceeds the typical 5 V CAN transceiver common-mode range. It is intended for power rail protection (VBAT, 5 V, 3.3 V supplies) upstream of CAN transceivers, not signal-line clamping.
What is the maximum surge current SM6T39CAY can handle at 8/20 µs waveform?
At 8/20 µs, SM6T39CAY supports up to 57 A peak pulse current (IPP), derived from its 69.7 V clamping voltage and 0.504 Ω dynamic resistance (VCL = VBR_max + RD × IPP → IPP = (69.7 − 41.0)/0.504 ≈ 57 A), per Table 2 and DS6905 Rev 11.
Does SM6T39CAY require a heatsink for 600 W surge dissipation?
No - the 600 W rating applies to a single 10/1000 µs pulse at Tamb = 25 °C with recommended FR4 PCB footprint (Figure 18). Thermal impedance is managed via copper area under leads (Figure 12); no external heatsink is needed for intermittent automotive surge events.
How does SM6T39CAY differ from SM6T39AY?
SM6T39CAY is bidirectional (symmetrical clamping for ± transients), while SM6T39AY is unidirectional (clamps only negative surges relative to cathode). The 'C' suffix denotes bidirectional functionality - critical for protecting floating or AC-coupled nodes like LIN or sensor bridges.
SM6T39CAY 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):
- 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:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
SM6T39CAY FAQ
1.How can I place an order for SM6T39CAY through Aetrix?
Please submit a Request for Quotation (RFQ) for SM6T39CAY 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 SM6T39CAY reliable?
The price and inventory of SM6T39CAY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM6T39CAY is usually 5 days.
3.What payment methods are accepted for SM6T39CAY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM6T39CAY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM6T39CAY?
SM6T39CAY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM6T39CAY 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 SM6T39CAY?
For technical support, including SM6T39CAY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM6T39CAY requirements.
6.How does Aetrix verify that SM6T39CAY is sourced from the original manufacturer or authorized distributors?
All SM6T39CAY 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 SM6T39CAY meets industry standards.
7.What is the process for return or replacement of SM6T39CAY?
All SM6T39CAY units undergo pre-shipment inspection (PSI). If there is an issue with SM6T39CAY, 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 SM6T39CAY part is unused and in its original packaging.
Return procedure for SM6T39CAY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SM6T39CAY Tags
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