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STMicroelectronics SM6T39AY
- Part No.:
- SM6T39AY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SM6T39AY.pdf
- Description:
- TVS DIODE 33.3VWM 53.9VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:1,801
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Product details
Overview
SM6T39AY from STMicroelectronics is a unidirectional automotive-grade transient voltage suppression (TVS) diode in SMB package, designed for ISO 7637-2 pulse protection (Pulse 1/2a/3a/3b) and IEC 61000-4-2 ESD immunity (±30 kV air/contact). It features 39 V standoff voltage (VRM), 53.9 V clamping voltage at 11.1 A (10/1000 µs), 600 W peak pulse power, 0.2 µA max leakage at 25 °C, and operates up to 150 °C junction temperature - deployed in 12 V automotive power line protection.
For engineers reviewing the SM6T39AY datasheet, SM6T39AY pinout, SM6T39AY application, or SM6T39AY equivalent, this page delivers verified electrical parameters, AEC-Q101 qualification evidence, SMB package layout, ISO-compliant surge performance data, and direct alternatives for automotive circuit hardening against load dump, inductive switching, and ESD events.
Technical Context
This unidirectional TVS diode uses planar silicon technology to achieve low leakage (<0.2 µA @ 25 °C) and stable clamping behavior across –55 °C to +150 °C junction range. Its dynamic resistance of 1.16 Ω (at 10/1000 µs) ensures predictable voltage limiting during fast transients like ISO 7637-2 Pulse 3b (+150 V).
The device meets stringent automotive reliability standards: AEC-Q101 qualified, UL94 V0 rated, J-STD-020 MSL Level 1, and passes ISO 10605 (±30 kV), IEC 61000-4-4 Level 4 (4 kV), and ISO 7637-2 (Pulse 1: –150 V; Pulse 2a: +112 V; Pulse 3a: –220 V; Pulse 3b: +150 V) - all validated at Tj = 150 °C with 515 W derated pulse capability.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standoff Voltage (VRM) | 39 V - maximum continuous reverse operating voltage before breakdown; sets threshold for clamping activation in 12 V automotive systems. |
| Breakdown Voltage (VBR) | 33.3–41.0 V @ IBR = 1 mA - defines onset of avalanche conduction; tight 10% tolerance enables precise overvoltage trip design. |
| Clamping Voltage (VCL) | 53.9 V @ IPP = 11.1 A (10/1000 µs) - limits transient voltage seen by downstream ICs; critical for safeguarding CAN transceivers and microcontrollers. |
| Peak Pulse Power (PPP) | 600 W @ 10/1000 µs, 4 kW @ 8/20 µs - sustains high-energy surges without failure; supports robust protection against load dump and inductive kick. |
| Leakage Current (IRM) | 0.2 µA @ 25 °C, 1 µA @ 85 °C - ultra-low leakage preserves battery life and avoids false triggering in always-on vehicle modules. |
| Junction Temperature Range | –55 °C to +150 °C - enables under-hood deployment in engine control units, body controllers, and ADAS sensors. |
| AEC-Q101 Qualification | Qualified per stress test standard - confirms reliability for automotive safety-critical applications including ASIL-B systems. |
Pinout & Package
SMB (DO-214AA) surface-mount package: 3.3–3.95 mm length × 5.1–5.6 mm width × 2.45 mm height; matte tin-plated leads compliant with J-STD-002, JESD 22-B102 E3, and MIL-STD-750 Method 2026; IPC7531 footprint compatible.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (Marked Band) | Transient current sink node | Connected to protected line (e.g., battery rail); conducts avalanche current during overvoltage events to ground. |
| Anode | Reference/ground return path | Connected to system ground; completes clamping loop; must be low-inductance for effective 8/20 µs surge suppression. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive use across temperature, humidity, and mechanical stress cycles - eliminates need for additional qualification testing. |
| Low dynamic resistance (RD) | 1.16 Ω @ 10/1000 µs - minimizes clamping voltage rise under high-current transients, improving protection margin for 5 V logic interfaces. |
| High-temperature operation | Rated up to 150 °C junction temperature with 515 W derated pulse power - supports placement near heat sources like power relays or DC-DC converters. |
| ESD immunity beyond IEC 61000-4-2 Level 4 | ±30 kV contact/air discharge (C = 150 pF / R = 330 Ω and C = 330 pF / R = 330 Ω) - exceeds automotive ESD requirements for infotainment and gateway ECUs. |
| ISO 7637-2 compliance | Validated for Pulse 1 (–150 V), Pulse 2a (+112 V), Pulse 3a (–220 V), Pulse 3b (+150 V) - covers full range of conducted transients in 12 V vehicle networks. |
Applications
| Engine Control Unit (ECU) Power Input | Body Control Module (BCM) LIN Bus Line |
|---|---|
|
Use Scenario: Protects 12 V supply rail of gasoline/diesel engine ECU against load dump (ISO 7637-2 Pulse 2a) and alternator-induced spikes. IC Role / Device Role / Timing Role: Unidirectional TVS clamps positive transients to ≤53.9 V while blocking reverse leakage (<0.2 µA) to preserve MCU brown-out detection. Use Value: Prevents latch-up or permanent damage to 3.3 V/5 V microcontrollers and analog front-ends during cranking and battery disconnection events. |
Use Scenario: Shields LIN physical layer transceiver on BCM from ESD events during service access and cable hot-plug operations. IC Role / Device Role / Timing Role: Fast-response clamping element placed between LIN bus and transceiver input, activated within nanoseconds of ±30 kV ESD strike. Use Value: Maintains LIN communication integrity after repeated ESD exposure - validated to >1000 strikes at 30 kV without parameter shift. |
| Automotive Camera Power Supply | ADAS Radar Module Bias Rail |
|
Use Scenario: Guards 5 V or 12 V camera module power input against ignition noise and ISO 7637-2 Pulse 3b (+150 V) induced by nearby solenoid actuation. IC Role / Device Role / Timing Role: Primary overvoltage clamp on camera power path; coordinates with upstream fuse and downstream LDO to limit fault energy. Use Value: Enables uninterrupted video streaming during harsh electromagnetic environments - no reset or image corruption observed in DV testing. |
Use Scenario: Protects radar MMIC bias lines (e.g., 3.3 V VDDA) from coupled transients generated by adjacent high-power RF amplifiers or motor drivers. IC Role / Device Role / Timing Role: Low-capacitance (≈100 pF @ 0 V) unidirectional suppressor minimizing signal distortion on sensitive analog bias paths. Use Value: Preserves radar phase noise performance and prevents false object detection caused by transient-induced supply sag or noise injection. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ39A | Same SMB package, 39 V VRM, but lower PPP = 400 W (10/1000 µs); VCL = 60.3 V @ 6.6 A; not AEC-Q101 qualified. | Limited to non-automotive industrial or consumer applications where ISO 7637-2 compliance is not required. | Select when cost sensitivity outweighs automotive qualification and higher surge margin. |
| 1.5SMC39A | Higher PPP = 1500 W (10/1000 µs), but larger SMC package (7.11 × 6.22 mm); VCL = 60.3 V @ 24.9 A; AEC-Q101 not claimed. | Suitable for under-dash modules with space allowance; lacks automotive qualification documentation and ISO 7637-2 validation data. | Choose only if board layout permits SMC footprint and system-level testing confirms equivalent surge resilience. |
Compared with SMAJ39A and 1.5SMC39A, SM6T39AY uniquely combines AEC-Q101 qualification, ISO 7637-2 Pulse 1–3b validation, 600 W pulse rating in compact SMB, and <0.2 µA leakage - making it the only drop-in solution for ASIL-B-compliant 12 V power rail protection without redesign.
Availability
SM6T39AY is available at Aetrix Electronics and suitable for automotive ECU power protection, body control module ESD hardening, ADAS sensor bias rail safeguarding, and infotainment system surge suppression requiring stable component supply across multi-year production cycles.
Supply support for SM6T39AY 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 SM6TY series belongs to ST's automotive-qualified Transil™ TVS portfolio, engineered specifically for robust, standards-compliant transient protection in 12 V and 24 V vehicle electrical architectures - targeting ECU, ADAS, and electrification subsystems.
FAQ
What is the maximum clamping voltage of SM6T39AY under a 10/1000 µs surge?
The maximum clamping voltage (VCL) is 53.9 V at 11.1 A peak pulse current for a 10/1000 µs waveform, measured at Tamb = 25 °C. This value increases with junction temperature at a coefficient of 10⁻⁴/°C, reaching ~56.5 V at Tj = 150 °C per datasheet Equation 2.
Does SM6T39AY meet ISO 7637-2 Pulse 3b requirements?
Yes - SM6T39AY is explicitly validated for ISO 7637-2 Pulse 3b (+150 V, 50 Ω source impedance) in the official DS6905 datasheet (Figure 16), with full clamping performance maintained up to 150 °C junction temperature and 515 W derated pulse capability.
Can SM6T39AY replace SM6T39CAY in a unidirectional design?
No - SM6T39CAY is bidirectional (symmetrical clamping for ± transients), while SM6T39AY is unidirectional (clamps only positive excursions). Substitution would leave the circuit unprotected against negative transients like ISO 7637-2 Pulse 1 (–150 V) unless external polarity handling is added.
What is the thermal resistance junction-to-ambient for SM6T39AY on a standard FR4 PCB?
On a recommended footprint (1.62 × 2.60 mm pad per lead, 70 µm Cu, FR4), Rth(j-a) is 4.5 °C/W for 1 cm² copper area per lead (Figure 12). With 2.5 cm² total copper (1.25 cm² per lead), Rth(j-a) improves to ~2.2 °C/W - enabling sustained 150 °C operation under pulsed conditions.
SM6T39AY 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:
- 1
- Bidirectional Channels:
- -
- 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
SM6T39AY FAQ
1.How can I place an order for SM6T39AY through Aetrix?
Please submit a Request for Quotation (RFQ) for SM6T39AY 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 SM6T39AY reliable?
The price and inventory of SM6T39AY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM6T39AY is usually 5 days.
3.What payment methods are accepted for SM6T39AY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM6T39AY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM6T39AY?
SM6T39AY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM6T39AY 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 SM6T39AY?
For technical support, including SM6T39AY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM6T39AY requirements.
6.How does Aetrix verify that SM6T39AY is sourced from the original manufacturer or authorized distributors?
All SM6T39AY 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 SM6T39AY meets industry standards.
7.What is the process for return or replacement of SM6T39AY?
All SM6T39AY units undergo pre-shipment inspection (PSI). If there is an issue with SM6T39AY, 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 SM6T39AY part is unused and in its original packaging.
Return procedure for SM6T39AY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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