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STMicroelectronics SM30T33AY
- Part No.:
- SM30T33AY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SM30T33AY.pdf
- Description:
- TVS DIODE 28VWM 45.4VC SMC
- Quantity:
- Payment:
- Shipping:
Inventory:3,524
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Product details
Overview
SM30T33AY from STMicroelectronics is an AEC-Q101-qualified unidirectional automotive TVS diode in SMC package, designed to clamp transient overvoltages up to 45.4 V (at 168 A, 8/20 µs) while sustaining 3000 W peak pulse power (10/1000 µs) and operating at junction temperatures up to +175 °C. It provides ESD protection exceeding ±30 kV (IEC 61000-4-2, C = 150 pF/R = 330 Ω) and ISO 10605 (C = 330 pF/R = 330 Ω), with low leakage current of 0.2 µA at 25 °C for battery-sensitive circuits.
For engineers reviewing the SM30T33AY datasheet, SM30T33AY pinout, SM30T33AY application, or SM30T33AY equivalent, this device serves as a high-reliability surge protector for 12 V and 24 V automotive power nets-specifically targeting load dump, ISO 7637-2 pulses (Pulse 1, 2a, 3a, 3b), and ESD events in engine control units, body controllers, and ADAS sensor interfaces.
Technical Context
The SM30T33AY employs planar silicon avalanche technology optimized for stable clamping under repetitive transients and high-temperature operation. Its breakdown voltage is tightly specified at 31.1–34.3 V (min–max at 25 °C, IBR = 1 mA), with temperature coefficient αT = 10 × 10⁻⁴ /°C enabling predictable VBR drift across –55 °C to +175 °C.
Clamping performance is defined by dynamic resistance RD = 41.4 mΩ and VCL = 45.4 V at IPP = 168 A (8/20 µs), ensuring low let-through voltage during fast surges. It meets IEC 61000-4-4 Level 4 (4 kV), ISO 7637-2 Pulse 1 (–150 V), Pulse 2a (+112 V), Pulse 3a (–220 V), and Pulse 3b (+150 V), with no derating required below VRM = 33 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Peak Pulse Power (10/1000 µs) | 3000 W - sustains full-rated surge energy without degradation in automotive ambient conditions |
| Clamping Voltage (8/20 µs, 168 A) | 45.4 V - limits downstream IC stress during fast transients like ESD or switching noise |
| Breakdown Voltage (IBR = 1 mA) | 31.1–34.3 V - ensures reliable turn-on before system overvoltage damages 33 V-rated components |
| Leakage Current (VRM = 33 V) | 0.2 µA at 25 °C - minimizes quiescent drain on always-on vehicle modules (e.g., CAN wake-up circuits) |
| Junction Temperature Range | –55 °C to +175 °C - supports under-hood placement near engines or powertrain ECUs |
| ESD Withstand (ISO 10605) | ±30 kV air/contact discharge - exceeds automotive OEM requirements for connector-level ESD immunity |
| Dynamic Resistance | 41.4 mΩ - enables low-voltage overshoot during high-current transients, improving system margin |
Pinout & Package
SM30T33AY is housed in a JEDEC-registered SMC (DO-214AB) surface-mount package with matte tin-plated leads and IPC-7531-compliant footprint. The device has two terminals: cathode (marked side) and anode.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Ground reference terminal for unidirectional clamping | Connected to system ground; defines polarity for forward-biased surge conduction path |
| Cathode | Protected line connection terminal | Connected to protected signal/power rail (e.g., 12 V battery feed); conducts avalanche current during overvoltage |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive-grade reliability including temperature cycling, HTRB, and mechanical shock per JESD22 standards |
| Low leakage current | 0.2 µA at VRM = 33 V and 25 °C - preserves battery life in always-on modules such as telematics and gateway ECUs |
| High-temperature operation | Rated for continuous operation up to TJ = +175 °C - suitable for under-hood applications without thermal derating |
| JEDEC SMC outline compliance | Package dimensions match MS-012AA (EIAJ DO-214AB) - ensures compatibility with standard SMT assembly and reflow profiles |
| UL94 V0 flammability rating | Self-extinguishing epoxy molding compound - satisfies automotive interior material safety requirements |
Applications
| Engine Control Unit (ECU) Power Input | Body Control Module (BCM) LIN Bus Line |
|---|---|
Use Scenario: Protects 12 V supply input of gasoline/diesel engine ECUs against load dump (ISO 7637-2 Pulse 5b) and alternator-induced transients. IC Role / Device Role / Timing Role: Unidirectional TVS clamps positive overvoltage spikes to <45.4 V while blocking reverse current during normal operation. Use Value: Prevents latch-up or permanent damage to MCU power rails and LDO regulators exposed to >100 V transients lasting up to 400 ms. |
Use Scenario: Shields LIN physical layer transceivers from ESD events during service port connection and cable coupling noise. IC Role / Device Role / Timing Role: Fast-response TVS suppresses ±30 kV contact discharge (ISO 10605) within nanoseconds, limiting voltage seen by LIN PHY pins. Use Value: Maintains bus communication integrity without requiring external series resistors or RC filters that degrade signal rise time. |
| ADAS Camera Power Rail | Electric Power Steering (EPS) Motor Driver Supply |
Use Scenario: Guards 12 V camera module input against ISO 7637-2 Pulse 1 (–150 V) and Pulse 3a (–220 V) during ignition and load switching. IC Role / Device Role / Timing Role: Low-capacitance (<100 pF) unidirectional TVS avoids signal distortion on high-speed image sensor interfaces (e.g., MIPI). Use Value: Enables robust operation in vibration-prone mounting locations while meeting ASIL-B functional safety constraints for vision systems. |
Use Scenario: Safeguards H-bridge gate driver ICs and current sense amplifiers from inductive kickback during EPS motor commutation. IC Role / Device Role / Timing Role: High-power (3000 W) clamping absorbs repetitive 8/20 µs surges generated by PWM-driven BLDC motors. Use Value: Eliminates need for redundant TVS stages, reducing BOM count and PCB area in space-constrained steering column assemblies. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional automotive TVS protection applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ33A | Lower peak pulse power (400 W), higher clamping voltage (53.3 V at 7.5 A), SMC package | Not rated for AEC-Q101; limited to non-safety-critical consumer or industrial use | Select only if surge energy is <10% of SM30T33AY's capability and automotive qualification is not required |
| 1.5KE33A | Higher leakage (5 µA), TO-218 package, lower thermal resistance but larger footprint | Designed for legacy through-hole designs; lacks ISO 10605 ESD rating and MSL level 1 moisture sensitivity compliance | Choose only for retrofitting existing through-hole boards where SMT rework is impractical |
Compared with SMAJ33A and 1.5KE33A, SM30T33AY delivers 7.5× higher surge power handling, certified automotive reliability, and tighter clamping-making it the sole choice for new 12 V/24 V power net designs requiring ASIL-compliant transient suppression.
Availability
SM30T33AY is available at Aetrix Electronics and suitable for automotive power management, ADAS sensor protection, and body electronics requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for SM30T33AY 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, analog, MEMS, and microcontroller solutions for automotive, industrial, and consumer markets.
The SM30TxxAY series belongs to ST's automotive-grade transient voltage suppression portfolio, engineered specifically to meet stringent ISO 7637-2, ISO 10605, and AEC-Q101 requirements for next-generation vehicle electrical architectures.
FAQ
What is the maximum clamping voltage of SM30T33AY under a 168 A, 8/20 µs surge?
The maximum clamping voltage is 45.4 V, measured at 168 A peak pulse current with an 8/20 µs waveform. This value is guaranteed across the full operating temperature range (–55 °C to +175 °C) and reflects worst-case dynamic resistance (41.4 mΩ) plus VBR drift. It ensures protected circuits remain below 48 V absolute maximum ratings commonly found in automotive MCUs and power ICs.
Does SM30T33AY require derating when mounted on a 1 oz. FR4 PCB?
No derating is required for standard mounting on 1 oz. (35 µm) FR4 with the recommended IPC-7531 footprint. Thermal impedance junction-to-ambient is 100 °C/W for single-pulse conditions, and the device maintains full 3000 W rating at Tamb = 25 °C. For continuous high-frequency surge exposure, copper pour under both terminals reduces Rth(j-a) to ~60 °C/W, further enhancing reliability.
Can SM30T33AY be used in bidirectional configurations?
No - SM30T33AY is a unidirectional TVS diode intended for DC power line protection. For bidirectional signal-line protection (e.g., CAN, LIN), ST offers the pin-compatible SM30T33CAY variant, which features symmetrical clamping in both polarities and identical electrical specs except for polarity and marking (3BANY). Mixing unidirectional and bidirectional types in the same circuit violates ISO 11898-2 requirements.
Is SM30T33AY compatible with lead-free reflow soldering processes?
Yes - it is qualified for lead-free reflow per J-STD-020 MSL Level 1, with a maximum peak temperature of 245 °C and 60-second dwell above 220 °C. The matte tin plating and ECOPACK-compliant epoxy ensure no voiding, tombstoning, or intermetallic formation during standard profile ramp rates (2–3 °C/s). ST recommends minimizing forced-air convection in the reflow zone to prevent component displacement.
SM30T33AY Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AB, SMC
- Series:
- SM30TY, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 28V
- Voltage - Breakdown (Min):
- 31.1V
- Voltage - Clamping (Max) @ Ipp:
- 45.4V
- Current - Peak Pulse (10/1000µs):
- 66.1A
- Power - Peak Pulse:
- 3000W (3kW)
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 175°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMC
SM30T33AY FAQ
1.How can I place an order for SM30T33AY through Aetrix?
Please submit a Request for Quotation (RFQ) for SM30T33AY 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 SM30T33AY reliable?
The price and inventory of SM30T33AY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM30T33AY is usually 5 days.
3.What payment methods are accepted for SM30T33AY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM30T33AY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM30T33AY?
SM30T33AY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM30T33AY 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 SM30T33AY?
For technical support, including SM30T33AY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM30T33AY requirements.
6.How does Aetrix verify that SM30T33AY is sourced from the original manufacturer or authorized distributors?
All SM30T33AY 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 SM30T33AY meets industry standards.
7.What is the process for return or replacement of SM30T33AY?
All SM30T33AY units undergo pre-shipment inspection (PSI). If there is an issue with SM30T33AY, 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 SM30T33AY part is unused and in its original packaging.
Return procedure for SM30T33AY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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