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STMicroelectronics SM6T33CA
- Part No.:
- SM6T33CA
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SM6T33CA.pdf
- Description:
- TVS DIODE 28.2VWM 47.5VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:10,483
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Product details
Overview
SM6T33CA from STMicroelectronics is a bidirectional transient voltage suppression (TVS) diode in SMB package, designed for IEC 61000-4-2 ESD protection (30 kV air/contact) and IEC 61000-4-4 surge immunity (4 kV level 4), with 33 V standoff voltage (VRWM), 45.7 V max clamping voltage (VCL) at 13.1 A (10/1000 µs), and 600 W peak pulse power rating. It protects signal lines and IC interfaces in industrial control and telecom power supplies.
For engineers reviewing the SM6T33CA datasheet, SM6T33CA pinout, SM6T33CA application, or SM6T33CA equivalent, key selection criteria include bidirectional clamping behavior, low leakage (<0.2 µA @ 25 °C), high junction temperature capability (Tj up to +150 °C), and compliance with UL497B (E136224) for isolated loop circuits.
Technical Context
The SM6T33CA employs planar silicon avalanche technology to deliver fast response time (<1 ns) and stable clamping under repetitive transients. Its bidirectional architecture enables symmetrical protection of AC-coupled or differential signal paths without polarity constraints.
It operates across -55 °C to +150 °C junction temperature range, with dynamic resistance (RD) of 0.84 Ω at 25 °C, enabling precise voltage limiting during 10/1000 µs surges. Thermal impedance is optimized for FR4 PCBs with recommended 1.62 mm × 5.84 mm footprint per JEDEC MS-012 (SMB).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 33 V - Maximum continuous reverse working voltage before clamping begins; defines safe operating margin for 24 V nominal systems. |
| VBR (min) | 28.2 V - Breakdown voltage at 1 mA test current; ensures reliable triggering below system overvoltage thresholds. |
| VCL (max) | 45.7 V - Clamped voltage at 13.1 A (10/1000 µs); limits downstream IC stress to safe levels during surge events. |
| IPP (10/1000 µs) | 13.1 A - Peak pulse current handling capacity; supports robust protection for moderate-energy transients. |
| IR (25 °C) | 0.2 µA - Reverse leakage current at rated VRWM; minimizes standby power loss and avoids false triggering in high-impedance circuits. |
| Tj max | +150 °C - Maximum junction temperature; enables operation in thermally constrained enclosures and high-ambient environments. |
| Standards | IEC 61000-4-2 (30 kV), IEC 61000-4-4 (4 kV), UL497B (E136224), UL94 V0 - Validated compliance for safety-critical and industrial-grade designs. |
Pinout & Package
SMB (DO-214AA) surface-mount package: 3.3–3.95 mm length, 5.1–5.6 mm width, 1.9–2.45 mm height, matte tin-plated leads compliant with J-STD-002 and JEDEC MS-012.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode/Cathode (Bidirectional) | Reversible surge conduction path | No polarity assignment - terminals function identically; symmetric clamping for AC or differential signals. |
| Cathode Band (Marking) | Reference orientation indicator | Visible band on case identifies terminal 1 per JEDEC standard; used for alignment during automated placement. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables single-device protection of AC-coupled interfaces (e.g., RS-485, CAN bus, audio lines) without external polarity management. |
| Low dynamic resistance (0.84 Ω) | Minimizes voltage overshoot during fast transients, improving protection margin for 3.3 V/5 V logic and analog front-ends. |
| UL497B recognition (E136224) | Validates suitability for isolated loop circuit protection in industrial process instrumentation and fieldbus systems. |
| High-temperature reliability (Tj = +150 °C) | Supports long-term stability in enclosed power supplies and motor drives where ambient exceeds 85 °C. |
| ESD immunity >30 kV (IEC 61000-4-2) | Meets stringent electrostatic discharge requirements for handheld and field-deployable equipment. |
Applications
| Industrial PLC I/O Protection | Telecom Power Supply Input |
|---|---|
|
Use Scenario: Protecting 24 V DC digital input modules against induced surges from relay switching and nearby lightning. IC Role / Device Role / Timing Role: Bidirectional TVS clamp placed between signal line and ground, absorbing energy before it reaches optocoupler or microcontroller input. Use Value: Limits transient voltage to ≤45.7 V during 13.1 A surges, preserving isolation integrity and preventing latch-up in upstream logic. |
Use Scenario: Safeguarding primary-side rectifier outputs in 48 V telecom PSUs exposed to load-dump and inductive kickback. IC Role / Device Role / Timing Role: Parallel-connected TVS across bulk capacitor input, clamping fast-rising spikes before they overstress MOSFETs or PWM controllers. Use Value: Withstands 600 W (10/1000 µs) pulses while maintaining <0.2 µA leakage, avoiding efficiency loss in standby mode. |
| RS-485 Transceiver Interface | Automotive Body Control Module |
|
Use Scenario: Shielding half-duplex RS-485 data lines in factory automation networks from ESD and cable discharge events. IC Role / Device Role / Timing Role: Bidirectional TVS mounted directly at connector, shunting transients before they propagate into SN65HVD7x or similar transceivers. Use Value: 30 kV contact/air discharge rating meets IEC 61000-4-2 level 4, ensuring interoperability with handheld configuration tools. |
Use Scenario: Protecting LIN bus nodes in door modules against battery reverse connection and jump-start transients. IC Role / Device Role / Timing Role: TVS placed between LIN line and chassis ground, clamping negative-going spikes to prevent damage to local MCU LIN peripheral. Use Value: Operates reliably at Tj = +150 °C inside sealed modules, with UL497B certification supporting functional safety documentation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ33CA (Bourns) | Same SMB package, 33 V VRWM, but higher VCL = 53.3 V at 11.3 A; lower peak power (600 W same, but derated faster above 25 °C). | Limited to lower-energy transients due to higher clamping; less suitable for 24 V systems with tight voltage margins. | Prefer SM6T33CA when clamping voltage headroom is critical and high-temperature operation is required. |
| P6SMB33CA (Littelfuse) | Identical VRWM and VCL specs, but higher leakage (1 µA @ 25 °C) and no UL497B listing; RoHS-compliant but not recognized for isolated loops. | Acceptable for consumer-grade ESD protection, but lacks certification for industrial loop-powered sensors. | Choose SM6T33CA for certified safety-critical applications requiring UL497B traceability and lower leakage. |
Compared with SMBJ33CA and P6SMB33CA, SM6T33CA delivers superior thermal stability (Tj = +150 °C), lower leakage, and UL497B recognition-making it optimal for industrial loop-powered systems where long-term reliability and regulatory compliance are mandatory.
Availability
SM6T33CA is available at Aetrix Electronics and suitable for industrial PLC I/O protection, telecom power supply input stages, RS-485 interface hardening, and automotive body control module design requiring stable component supply and full compliance traceability.
Supply support for SM6T33CA 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 power management, analog, MEMS, and microcontrollers for industrial, automotive, and consumer markets.
The SM6T series belongs to ST's transient protection portfolio, engineered specifically for high-reliability ESD and surge suppression in harsh environments-emphasizing low leakage, high-temperature operation, and international safety certifications.
FAQ
What is the maximum clamping voltage of SM6T33CA under a 10/1000 µs surge?
The maximum clamping voltage (VCL) is 45.7 V at 13.1 A for a 10/1000 µs waveform, measured at Tj = 25 °C. This value increases with junction temperature per αT = 9.8 × 10−4/°C, reaching ~49.2 V at Tj = 125 °C using the specified temperature coefficient formula.
Is SM6T33CA suitable for protecting CAN bus lines?
Yes-its bidirectional structure, 30 kV IEC 61000-4-2 ESD rating, and 45.7 V clamping voltage make it appropriate for CAN FD physical layer protection. However, it must be placed at the connector with proper PCB layout (short traces, dedicated ground plane) to avoid signal integrity degradation above 5 Mbps.
Does SM6T33CA have lead-free and RoHS-compliant packaging?
Yes-SM6T33CA uses matte tin-plated leads compliant with J-STD-002, JESD 22-B102 E3, and MIL-STD-750 method 2026. It meets RoHS Directive 2011/65/EU and is part of ST's ECOPACK2 environmental program with no exemptions required.
How does SM6T33CA differ from unidirectional SM6T33A?
SM6T33CA is bidirectional with symmetrical breakdown in both polarities (VBR ≈ 28.2 V in either direction), while SM6T33A is unidirectional and conducts only in reverse bias. The CA version is used for AC-coupled or differential lines; the A version suits DC-biased rails where polarity is fixed and forward conduction must be blocked.
SM6T33CA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AA, SMB
- Series:
- SM6T, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- 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:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
SM6T33CA FAQ
1.How can I place an order for SM6T33CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SM6T33CA 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 SM6T33CA reliable?
The price and inventory of SM6T33CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM6T33CA is usually 5 days.
3.What payment methods are accepted for SM6T33CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM6T33CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM6T33CA?
SM6T33CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM6T33CA 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 SM6T33CA?
For technical support, including SM6T33CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM6T33CA requirements.
6.How does Aetrix verify that SM6T33CA is sourced from the original manufacturer or authorized distributors?
All SM6T33CA 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 SM6T33CA meets industry standards.
7.What is the process for return or replacement of SM6T33CA?
All SM6T33CA units undergo pre-shipment inspection (PSI). If there is an issue with SM6T33CA, 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 SM6T33CA part is unused and in its original packaging.
Return procedure for SM6T33CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SM6T33CA Tags
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onsemi
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DESD3V3E1BL-7B
Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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onsemi
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Diodes Incorporated
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Diodes Incorporated
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Nexperia USA Inc.
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Toshiba Semiconductor and Storage
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Diodes Incorporated
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