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STMicroelectronics SM6T33AY
- Part No.:
- SM6T33AY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SM6T33AY.pdf
- Description:
- TVS DIODE 28.2VWM 45.7VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:14,387
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Product details
Overview
SM6T33AY from STMicroelectronics is a unidirectional automotive-grade transient voltage suppression (TVS) diode in SMB package, designed for ISO 7637-2 pulse protection in 12 V vehicle systems. It features a 33 V standoff voltage (VRM), 45.7 V clamping voltage at 13.1 A (10/1000 µs), 600 W peak pulse power, ≤0.2 µA leakage at 25 °C, and AEC-Q101 qualification for under-hood reliability.
For engineers reviewing the SM6T33AY datasheet, SM6T33AY pinout, SM6T33AY application, or SM6T33AY equivalent, this device is selected for robust ESD/ISO surge protection in automotive power line interfaces-especially where low leakage, high junction temperature operation (up to +150 °C), and precise clamping performance are critical for CAN/LIN bus power rails and sensor supply lines.
Technical Context
The SM6T33AY employs planar silicon technology to achieve stable breakdown behavior and low dynamic resistance (RD = 0.84 Ω) across temperature, enabling consistent clamping during repetitive transients. Its unidirectional polarity supports cathode-to-rail configuration for battery-supplied circuits, with reverse standoff rated at 33 V and guaranteed breakdown between 28.2 V (min) and 34.7 V (max) at 1 mA.
It meets IEC 61000-4-2 (±30 kV air/contact), ISO 10605 (±30 kV, C = 330 pF/R = 330 Ω), and ISO 7637-2 Pulse 1 (−150 V), Pulse 2a (+112 V), Pulse 3a (−220 V), and Pulse 3b (+150 V) requirements-making it suitable for front-end protection of ECUs, body control modules, and ADAS power inputs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standoff Voltage (VRM) | 33 V - Maximum continuous reverse operating voltage before conduction begins; sets minimum system operating margin. |
| Breakdown Voltage (VBR) | 28.2–34.7 V @ 1 mA - Confirmed voltage range at specified test current; ensures predictable turn-on during surges. |
| Clamping Voltage (VCL) | 45.7 V @ 13.1 A (10/1000 µs) - Peak voltage seen by protected circuit during worst-case transient; defines safe downstream voltage ceiling. |
| Peak Pulse Power (PPP) | 600 W @ 10/1000 µs - Sustained energy-handling capability at room temperature; de-rates to 515 W at Tj = 150 °C. |
| Leakage Current (IRM) | ≤0.2 µA @ 25 °C, ≤1 µA @ 85 °C - Minimal DC loading on sensitive 12 V rails; preserves battery life and signal integrity. |
| Junction Temperature Range | −55 to +150 °C - Enables placement near heat sources (e.g., engine bay ECUs) without derating loss. |
| AEC-Q101 Qualified | Validated for automotive use per stress-test standard - confirms reliability for production vehicles over full lifetime. |
Pinout & Package
SM6T33AY is housed in an SMB (DO-214AA) surface-mount package with two terminals: Cathode (marked band) and Anode. The package measures 3.3–3.95 mm (D) × 5.1–5.6 mm (E) × 1.9–2.45 mm (A1), with matte tin-plated leads compliant to J-STD-002 and IPC7531 footprint standards.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (banded end) | Transient current sink | Connected to protected line (e.g., 12 V rail); conducts surge current to ground when voltage exceeds VRM. |
| Anode | Reference / Ground return | Typically tied to chassis or system ground; completes low-inductance path for clamped energy dissipation. |
Key Features
| Feature | Design Value |
|---|---|
| Automotive qualification | AEC-Q101 certified - validated for vibration, thermal cycling, and humidity exposure in automotive environments. |
| Low dynamic resistance | RD = 0.84 Ω - Minimizes clamping voltage rise under high-current pulses, improving protection margin. |
| High-temperature stability | Operates up to +150 °C junction temperature with <10 ppm/°C voltage drift (αT = 9.8 × 10⁻⁴/°C) - maintains specification across engine bay conditions. |
| ESD robustness | ±30 kV contact/air discharge (IEC 61000-4-2 & ISO 10605) - protects against human-body-model and machine-model ESD events in assembly and field use. |
| Lead finish | Matte tin plating - ensures reliable solderability per J-STD-020 MSL Level 1 and whisker resistance per JESD201 Class 2. |
Applications
| Body Control Module (BCM) Power Input | Infotainment System USB Power Rail |
|---|---|
|
Use Scenario: 12 V battery-fed power input subjected to load dump and ISO 7637-2 Pulse 1/2a/3a/3b transients. IC Role / Device Role / Timing Role: Primary front-end TVS clamp limiting voltage to <46 V during 150 V negative spikes and 112 V positive surges. Use Value: Prevents damage to downstream DC-DC converters and microcontrollers by clamping within 45.7 V at 13.1 A, with <0.2 µA standby leakage preserving quiescent current budget. |
Use Scenario: 5 V USB VBUS line exposed to ESD and hot-plug transients in center-stack infotainment units. IC Role / Device Role / Timing Role: Secondary protection stage after upstream fuse and common-mode choke; suppresses fast ESD events before reaching USB PHY IC. Use Value: Delivers ±30 kV ESD immunity (IEC 61000-4-2) with <1 ns response time and <0.84 Ω RD, minimizing voltage overshoot into USB controller's 5.5 V absolute max rating. |
| ADAS Camera Power Supply | Electric Power Steering (EPS) Sensor Interface |
|
Use Scenario: 12 V camera module supply line in front bumper, subject to repeated cranking transients and ESD from housing contact. IC Role / Device Role / Timing Role: Unidirectional TVS placed between input capacitor and LDO regulator input to absorb ISO 7637-2 Pulse 3b (+150 V) and ESD bursts. Use Value: Maintains <46 V clamping at 13.1 A while operating continuously at +125 °C ambient, ensuring no degradation in dark-current noise or image sensor startup reliability. |
Use Scenario: 5 V reference supply for torque/position sensors in EPS motor control unit, requiring ultra-low leakage and stable clamping. IC Role / Device Role / Timing Role: Low-leakage (≤0.2 µA) TVS on sensor VREF line to prevent false triggering during ESD events without affecting ADC reference accuracy. Use Value: Enables <1 LSB error contribution from leakage-induced IR drop, supporting 12-bit sensor resolution even at 85 °C ambient. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ33A (Bourns) | Same SMB package, 33 V VRM, but higher VCL = 53.3 V @ 11.3 A (10/1000 µs); RD = 1.05 Ω. | Higher clamping voltage reduces protection margin for 5 V logic rails downstream of LDOs. | Select when cost sensitivity outweighs clamping performance; verify downstream IC absolute max ratings exceed 53.3 V. |
| P6SMB33A (Littelfuse) | Identical VRM/VBR spec, but lower PPP = 600 W only at Tamb = 25 °C; no published Tj = 150 °C derating curve. | Lacks documented high-temperature surge capability - unsuitable for under-hood placements above 105 °C ambient. | Prefer for cabin-mounted modules only; avoid where junction temperature may exceed 125 °C during sustained operation. |
Compared with SMAJ33A and P6SMB33A, SM6T33AY delivers tighter clamping (45.7 V vs. ≥53.3 V), lower dynamic resistance (0.84 Ω vs. ≥1.05 Ω), and verified 515 W surge capability at +150 °C - making it the preferred choice for thermally demanding automotive power rail protection.
Availability
SM6T33AY is available at Aetrix Electronics and suitable for automotive electronic control units, ADAS camera modules, infotainment power supplies, and electric power steering systems requiring stable component supply with AEC-Q101 assurance and long-term production continuity.
Supply support for SM6T33AY 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-grade Transil™ TVS portfolio, engineered specifically for ISO 7637-2 and ISO 10605 compliance in 12 V/24 V vehicle architectures - emphasizing low leakage, high-temperature stability, and repeatable clamping performance.
FAQ
What is the maximum clamping voltage of SM6T33AY under a 10/1000 µs surge?
The maximum clamping voltage (VCL) of SM6T33AY is 45.7 V at 13.1 A for a 10/1000 µs waveform, measured at 25 °C ambient. This value increases slightly with junction temperature due to the αT coefficient of 9.8 × 10⁻⁴/°C, reaching approximately 47.2 V at Tj = 150 °C.
Is SM6T33AY suitable for protecting a 5 V USB interface?
Yes - when used downstream of a 12 V-to-5 V DC-DC converter or LDO, SM6T33AY provides effective secondary protection against ESD and coupled transients. Its 45.7 V clamping does not directly apply to the 5 V rail, but its low leakage (<0.2 µA) and fast response prevent interference with USB PHY operation and meet IEC 61000-4-2 ±30 kV requirements.
How does SM6T33AY differ from bidirectional SM6T33CAY?
SM6T33AY is unidirectional and intended for DC-biased lines like 12 V battery rails, conducting only in reverse breakdown. SM6T33CAY is bidirectional, symmetric for AC-coupled signals such as CAN bus lines, with identical clamping in both polarities. Their marking, packaging, and thermal specs are identical, but circuit topology determines selection.
Does SM6T33AY require derating at elevated ambient temperatures?
Yes - its peak pulse power de-rates from 600 W at 25 °C to 515 W at Tj = 150 °C, per Figure 3 in DS6905. PCB copper area and thermal vias must be optimized per Figure 12 to maintain junction temperature below 150 °C during surge events, especially in enclosed engine bay environments.
SM6T33AY 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):
- 28.2V
- Voltage - Breakdown (Min):
- 31.4V
- Voltage - Clamping (Max) @ Ipp:
- 45.7V
- Current - Peak Pulse (10/1000µs):
- 13.1A
- 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
SM6T33AY FAQ
1.How can I place an order for SM6T33AY through Aetrix?
Please submit a Request for Quotation (RFQ) for SM6T33AY 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 SM6T33AY reliable?
The price and inventory of SM6T33AY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM6T33AY is usually 5 days.
3.What payment methods are accepted for SM6T33AY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM6T33AY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM6T33AY?
SM6T33AY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM6T33AY 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 SM6T33AY?
For technical support, including SM6T33AY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM6T33AY requirements.
6.How does Aetrix verify that SM6T33AY is sourced from the original manufacturer or authorized distributors?
All SM6T33AY 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 SM6T33AY meets industry standards.
7.What is the process for return or replacement of SM6T33AY?
All SM6T33AY units undergo pre-shipment inspection (PSI). If there is an issue with SM6T33AY, 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 SM6T33AY part is unused and in its original packaging.
Return procedure for SM6T33AY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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