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STMicroelectronics SM15T39AY
- Part No.:
- SM15T39AY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SM15T39AY.pdf
- Description:
- TVS DIODE 33.3VWM 69.7VC SMC
- Quantity:
- Payment:
- Shipping:
Inventory:2,309
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Product details
Overview
SM15T39AY from STMicroelectronics is an AEC-Q101-qualified unidirectional automotive TVS diode in SMC package, designed to clamp transient surges up to 1500 W (10/1000 µs) and 10 kW (8/20 µs), with a nominal breakdown voltage of 39 V, clamping voltage of 53.9 V at 28 A, and leakage current ≤0.2 µA at 25 °C - deployed in 12 V automotive power line protection against ISO 7637-2 Pulse 1 (−150 V) and ISO 10605 ESD (±30 kV).
For engineers reviewing the SM15T39AY datasheet, SM15T39AY pinout, SM15T39AY application, or SM15T39AY equivalent, this device is selected for high-reliability DC power rail surge suppression where low leakage, high junction temperature operation (up to +150 °C), and validated ISO/IEC/ISO7637 compliance are mandatory.
Technical Context
The SM15T39AY uses planar silicon technology to achieve stable VBR (33.3–41.0 V), low dynamic resistance (0.461 Ω), and minimal capacitance (<100 pF at 1 MHz), enabling fast response to sub-microsecond transients while maintaining signal integrity in adjacent circuits. Its unidirectional configuration provides forward conduction path only during negative surges on the protected line relative to ground.
Thermal performance is optimized for automotive under-hood environments: maximum junction temperature is +150 °C, and peak pulse power derates linearly to 1250 W at Tj = 150 °C per Figure 3, supported by JEDEC-registered SMC footprint and IPC7531-compliant copper land pattern.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Breakdown Voltage (VBR) | 33.3 V min / 41.0 V max at IBR = 1 mA - defines precise clamping onset threshold for 12 V system overvoltage events. |
| Clamping Voltage (VCL) | 53.9 V at IPP = 28 A (10/1000 µs) - ensures downstream 60 V-rated components remain within safe operating area during surge. |
| Peak Pulse Power | 1500 W (10/1000 µs), 10 kW (8/20 µs) - meets ISO 7637-2 Pulse 1 (−150 V) and Pulse 3a (−220 V) energy requirements. |
| Leakage Current (IR) | ≤0.2 µA at VRM = 31.5 V and 25 °C - prevents battery drain in always-on automotive modules. |
| Junction Temperature Range | −55 °C to +150 °C - supports engine compartment mounting without thermal derating loss of surge capability. |
| Dynamic Resistance (RD) | 0.461 Ω - minimizes VCL rise under high-current transients, improving clamping precision. |
| ESD Withstand | ±30 kV (air/contact, ISO 10605, C = 150/330 pF, R = 330 Ω) - exceeds IEC 61000-4-2 Level 4 for infotainment and sensor interfaces. |
Pinout & Package
SM15T39AY is housed in an SMC (DO-214AB) surface-mount package with two terminals: Cathode (K) and Anode (A). The package measures 5.55–6.25 mm × 7.75–8.15 mm × 2.45 mm max height, features matte tin-plated leads compliant with J-STD-002 and MIL-STD-750 Method 2026, and is rated MSL Level 1 per J-STD-020.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (A) | Transient return path to ground | Connected to chassis or system ground; completes clamping loop during negative-voltage transients (e.g., ISO 7637-2 Pulse 1). |
| Cathode (K) | Protected line connection | Connected to 12 V supply rail or sensitive load input; conducts when reverse voltage exceeds VBR, shunting surge current to ground. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive under-hood use including temperature cycling, humidity bias, and mechanical shock per stress test requirements. |
| Low leakage at high temperature | ≤1 µA at 85 °C and VRM = 31.5 V - enables long-term reliability in always-powered telematics and ADAS modules. |
| High surge robustness | Withstands 10 kW (8/20 µs) pulses - protects against load dump and alternator switching transients in 12 V systems. |
| Planar junction construction | Delivers stable VBR temperature coefficient (αT = 10 × 10−4/°C) and low capacitance (<100 pF) for noise-sensitive CAN/LIN bus power rails. |
| JEDEC-compliant SMC footprint | Enables drop-in PCB replacement with standard reflow profile (peak 240–245 °C) and IPC7531 land pattern compatibility. |
Applications
| Engine Control Unit (ECU) Power Input | Body Control Module (BCM) Battery Rail |
|---|---|
|
Use Scenario: Protection of 12 V supply input to microcontroller and analog sensor circuitry against load dump and jump-start transients. IC Role / Device Role / Timing Role: Unidirectional TVS clamps negative-going surges (e.g., ISO 7637-2 Pulse 1: −150 V) while remaining non-conductive during normal operation. Use Value: Limits VCL to 53.9 V at 28 A, ensuring downstream 60 V-rated LDOs and MCU IOs stay within absolute maximum ratings. |
Use Scenario: Surge suppression on BCM main battery feed powering door locks, lighting, and HVAC actuators. IC Role / Device Role / Timing Role: Absorbs repetitive 8/20 µs transients from relay coil flyback and motor commutation spikes. Use Value: 10 kW peak power rating handles worst-case ISO 7637-2 Pulse 3b (+150 V) without degradation over 100,000 cycles. |
| Infotainment System USB Power Port | ADAS Camera Module Power Line |
|
Use Scenario: ESD and surge protection for 5 V USB VBUS derived from vehicle 12 V via buck converter. IC Role / Device Role / Timing Role: Clamps ±30 kV contact discharge (ISO 10605) before transients reach USB PHY and PMIC inputs. Use Value: 0.2 µA leakage at 25 °C prevents standby current increase in always-on infotainment head units. |
Use Scenario: Front-facing camera power rail exposed to engine bay EMI and ignition noise. IC Role / Device Role / Timing Role: Suppresses fast-rising transients (tr < 1 ns) from nearby solenoid drivers using low-capacitance planar junction. Use Value: Junction capacitance <100 pF at 1 MHz avoids signal distortion on 12 V analog video or MIPI D-PHY power lines. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional automotive TVS applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ39A | Lower peak power (400 W), higher VCL (67 V at 20 A), SMC package but not AEC-Q101 qualified. | Limited to non-safety-critical consumer-grade 12 V accessories; unsuitable for ECU/BCM deployment. | Select only for cost-sensitive non-automotive designs where AEC-Q101 and ISO7637-2 compliance are not required. |
| 1.5KE39A | Higher VCL (60 V at 25 A), axial DO-201 package, no automotive qualification, 1.5 kW rating at 25 °C only. | Requires through-hole assembly; thermal derating above 75 °C invalidates surge rating for under-hood use. | Use only in legacy industrial power supplies with ambient <70 °C and no vibration/moisture exposure. |
Compared with SMAJ39A and 1.5KE39A, SM15T39AY delivers superior automotive-grade reliability via AEC-Q101 validation, tighter VCL (53.9 V vs. ≥60 V), lower leakage, and guaranteed 1500 W performance at +150 °C junction temperature - critical for modern ECU and ADAS power integrity.
Availability
SM15T39AY is available at Aetrix Electronics and suitable for engine control units, body control modules, infotainment power supplies, and ADAS camera modules requiring stable component supply across automotive production lifecycles.
Supply support for SM15T39AY 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 specializing in automotive, industrial, and power management ICs, with manufacturing and R&D centers across Europe, Asia, and the Americas.
The SM15TxxAY series belongs to ST's automotive-grade transient voltage suppressor portfolio, engineered specifically for robust 12 V/24 V vehicle electrical system protection against ISO 7637-2, ISO 10605, and IEC 61000-4-4 threats.
FAQ
What is the maximum clamping voltage of SM15T39AY under a 10/1000 µs surge?
The maximum clamping voltage is 53.9 V at 28 A for a 10/1000 µs waveform, measured at Tamb = 25 °C. This value increases with junction temperature per αT = 10 × 10−4/°C, reaching ~56.2 V at Tj = 150 °C using the formula VCL(Tj) = VCL(25 °C) × [1 + αT × (Tj − 25)].
Is SM15T39AY compatible with lead-free reflow soldering?
Yes - SM15T39AY is RoHS-compliant and qualified for lead-free reflow with a peak temperature of 240–245 °C for 2–3 seconds, per ST's recommended profile (Figure 25, DS6928 Rev 6). Matte tin plating meets J-STD-002 and MIL-STD-750 Method 2026 solderability requirements.
How does SM15T39AY differ from the bidirectional SM15T39CAY?
SM15T39AY is unidirectional (anode-to-cathode conduction only), intended for DC power rail protection where polarity is fixed. SM15T39CAY is bidirectional (symmetrical clamping), used in AC-coupled or differential signal lines like CAN bus. Their VBR, VCL, and surge ratings are identical, but pinout interpretation differs: CAY requires both terminals to be isolated from ground reference.
Can SM15T39AY protect against ISO 7637-2 Pulse 2a (+112 V)?
Yes - SM15T39AY clamps ISO 7637-2 Pulse 2a (112 V, 50 ms) effectively due to its 1500 W 10/1000 µs rating and thermal mass. At Tj = 125 °C, it sustains up to 1250 W, exceeding the energy content of Pulse 2a (≈1.2 J), and its VCL remains below 60 V, protecting typical 60 V-rated automotive regulators.
SM15T39AY Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AB, SMC
- Series:
- SM15TY, 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:
- 69.7V
- Current - Peak Pulse (10/1000µs):
- 143A (8/20µs)
- Power - Peak Pulse:
- 1500W (1.5kW)
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMC
SM15T39AY FAQ
1.How can I place an order for SM15T39AY through Aetrix?
Please submit a Request for Quotation (RFQ) for SM15T39AY 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 SM15T39AY reliable?
The price and inventory of SM15T39AY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM15T39AY is usually 5 days.
3.What payment methods are accepted for SM15T39AY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM15T39AY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM15T39AY?
SM15T39AY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM15T39AY 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 SM15T39AY?
For technical support, including SM15T39AY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM15T39AY requirements.
6.How does Aetrix verify that SM15T39AY is sourced from the original manufacturer or authorized distributors?
All SM15T39AY 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 SM15T39AY meets industry standards.
7.What is the process for return or replacement of SM15T39AY?
All SM15T39AY units undergo pre-shipment inspection (PSI). If there is an issue with SM15T39AY, 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 SM15T39AY part is unused and in its original packaging.
Return procedure for SM15T39AY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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