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STMicroelectronics SMB6F33A
- Part No.:
- SMB6F33A
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-221AA, SMB Flat Leads
- Datasheet:
-
SMB6F33A.pdf
- Description:
- TVS DIODE 33VWM 53.3VC SMBFLAT
- Quantity:
- Payment:
- Shipping:
Inventory:8,754
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Product details
Overview
SMB6F33A from STMicroelectronics is a unidirectional 600 W transient voltage suppression (TVS) diode in SMB Flat package, designed to protect sensitive electronics against ESD and surge events. It features a standoff voltage (VRM) of 33 V, clamping voltage (VCL) of 53.3 V at 11.8 A (10/1000 µs), and operates up to 175 °C junction temperature - ideal for automotive power line and industrial I/O port protection.
For engineers reviewing the SMB6F33A datasheet, SMB6F33A pinout, SMB6F33A application, or SMB6F33A equivalent, key selection criteria include clamping performance under 10/1000 µs surges, low leakage (<0.2 µA at 25 °C), flat SMB package compatibility with high-density PCB layouts, and compliance with IEC 61000-4-2 level 4 (±30 kV contact/air discharge).
Technical Context
This TVS diode uses planar silicon technology to achieve low leakage current and stable breakdown behavior across wide temperature ranges (–55 °C to +175 °C). Its unidirectional configuration provides asymmetric clamping suitable for DC-biased signal or power lines where reverse conduction must be blocked.
The device delivers 600 W peak pulse power (10/1000 µs) at 25 °C and retains 470 W at Tj = 175 °C, with dynamic resistance (RD) of 1.08 Ω - enabling precise voltage limiting during fast transients such as ISO 7637-2 pulses or lightning-induced surges in 12 V/24 V systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standoff Voltage (VRM) | 33 V - maximum continuous reverse operating voltage before clamping begins |
| Breakdown Voltage (VBR) | 36.7–40.5 V at 1 mA - ensures reliable triggering above normal operating voltage with margin |
| Clamping Voltage (VCL) | 53.3 V at 11.8 A (10/1000 µs) - limits transient voltage seen by downstream ICs |
| Peak Pulse Power (PPP) | 600 W (10/1000 µs) - protects against common automotive load dump and inductive switching events |
| Leakage Current (IRM) | 0.2 µA at 25 °C - minimizes standby power loss and avoids false triggering in high-impedance circuits |
| Junction Temperature Range | –55 °C to +175 °C - supports under-hood automotive and industrial environments without derating |
| ESD Robustness | ±30 kV (IEC 61000-4-2, contact/air) - exceeds level 4 for robust system-level ESD immunity |
Pinout & Package
The SMB6F33A is housed in an SMB Flat package (JEDEC DO-214AA), measuring 3.95 mm × 5.60 mm × 1.10 mm with 2.20 mm lead width and 1 mm profile height - optimized for automated assembly and thermal dissipation on standard FR4 PCBs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (marked band) | Surge current sink | Connected to protected line; conducts transient energy to ground when voltage exceeds VBR |
| Anode | Reference/return path | Typically tied to system ground or lower-potential rail; completes clamping loop during overvoltage |
Key Features
| Feature | Design Value |
|---|---|
| Flat 1 mm profile | Enables use in space-constrained applications like automotive ECUs and IoT sensor nodes without compromising creepage |
| Low dynamic resistance (1.08 Ω) | Reduces clamping voltage overshoot during fast-rising transients (e.g., EFT bursts), improving protection margin |
| Matte tin-plated leads | Ensures reliable solderability per J-STD-002/E3 and supports lead-free reflow (240–245 °C peak) |
| UL94 V0 flammability rating | Meets safety requirements for enclosed industrial and automotive enclosures exposed to potential arc sources |
| MSL Level 1 moisture sensitivity | Allows indefinite floor life without dry pack storage - simplifies manufacturing logistics and inventory handling |
Applications
| Automotive Power Line Protection | Industrial PLC Digital I/O |
|---|---|
Use Scenario: 12 V battery line in engine control unit subjected to load dump (ISO 7637-2 Pulse 5a) and alternator ripple. IC Role / Device Role / Timing Role: Unidirectional TVS placed between battery rail and local regulator input to clamp transients before LDO or MCU power pins. Use Value: Clamps to 53.3 V at 11.8 A, preventing regulator overvoltage failure while maintaining <0.2 µA leakage to avoid battery drain. | Use Scenario: 24 V digital input channel in programmable logic controller exposed to field-wiring induced surges (IEC 61000-4-4 level 4). IC Role / Device Role / Timing Role: Primary surge suppressor on front-end signal conditioning circuit, upstream of optocoupler or Schmitt trigger. Use Value: Withstands 4 kV EFT bursts and clamps within 1 ns, preserving signal integrity and eliminating need for secondary filtering. |
| USB Port ESD Protection | Smart Meter Communication Interface |
Use Scenario: VBUS line of USB 2.0 host port in industrial gateway requiring ±30 kV IEC 61000-4-2 immunity. IC Role / Device Role / Timing Role: Standoff-rated TVS placed directly at connector to shunt ESD current before USB transceiver. Use Value: Low capacitance (<100 pF at 1 V) avoids signal distortion; 33 V VRM prevents conduction during normal 5 V operation. | Use Scenario: RS-485 transceiver bus line in utility smart meter installed in outdoor substations. IC Role / Device Role / Timing Role: Bidirectional protection not required; unidirectional SMB6F33A used with pull-up bias to protect against negative-going surges on A/B lines. Use Value: 175 °C max junction temperature enables operation inside sealed, thermally isolated meter housings without thermal derating. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ33A (Bourns) | Same SMB package, 600 W rating, but higher VBR (36.7–40.5 V vs. Bourns' 36.7–42.2 V) and slightly higher VCL (53.3 V vs. 54.0 V) | Identical placement and footprint; minor clamping variation acceptable in most 12–24 V systems | Select when sourcing flexibility is needed and board layout allows ±0.7 V clamping tolerance |
| SMAJ33A (Littelfuse) | SMA package (smaller footprint, 4.5 mm × 2.7 mm), same 33 V VRM, but lower PPP (400 W) and higher RD (1.25 Ω) | Requires PCB redesign; less effective for high-energy transients like load dump due to lower power rating | Choose only if space constraints prohibit SMB and surge energy is limited to <400 W (e.g., signal-line only) |
Compared with SMBJ33A and SMAJ33A, SMB6F33A offers superior thermal robustness (175 °C TJ max), tighter VCL consistency (53.3 V), and MSL Level 1 handling - making it preferred for automotive and high-reliability industrial designs where long-term stability and manufacturability are critical.
Availability
SMB6F33A is available at Aetrix Electronics and suitable for automotive power line protection, industrial PLC I/O modules, USB host port hardening, and smart meter communication interfaces requiring stable component supply across extended temperature and surge stress conditions.
Supply support for SMB6F33A 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 automotive, industrial, and power management solutions with broad analog, power, and protection device portfolios.
The SMB6FxxA series belongs to ST's high-reliability TVS diode product line, engineered specifically for harsh-environment surge protection where low leakage, high-temperature operation, and consistent clamping performance are mandatory.
FAQ
What is the maximum clamping voltage of SMB6F33A under a 10/1000 µs surge?
The maximum clamping voltage (VCL) is 53.3 V at 11.8 A for a 10/1000 µs waveform, measured at 25 °C ambient. This value increases with junction temperature per the αT coefficient (10 × 10⁻⁴/°C), reaching ~58.5 V at 175 °C - a critical design parameter for ensuring downstream ICs remain within absolute maximum ratings during sustained surges.
Can SMB6F33A be used in bidirectional protection configurations?
No - SMB6F33A is a unidirectional TVS diode, intended for DC-biased lines where reverse conduction must be blocked. For AC or bipolar signal lines, a bidirectional variant (e.g., SMB6F33CA) or back-to-back unidirectional pair is required; using SMB6F33A alone in bidirectional applications risks permanent failure during negative transients.
How does the SMB Flat package improve thermal performance compared to standard SMB?
The SMB Flat package reduces profile height to 1.10 mm and increases copper pad area under each lead, lowering thermal resistance (Rth(j-a)) to ~120 °C/W on 1 cm² copper - 25% better than legacy SMB. This enables higher sustained power handling and improved reliability in thermally constrained automotive and industrial enclosures.
Is SMB6F33A compliant with automotive AEC-Q200 stress testing?
No - SMB6F33A is not AEC-Q200 qualified. While it meets IEC 61000-4-2/4-4 and operates up to 175 °C, ST does not list it in their AEC-Q200 stress-tested portfolio. For automotive safety-critical applications, designers should verify qualification status via ST's official part search or consult ST's automotive-grade alternatives (e.g., SMA6J33A-Q).
SMB6F33A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-221AA, SMB Flat Leads
- Series:
- SMB6FxxA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 33V (Max)
- Voltage - Breakdown (Min):
- 36.7V
- Voltage - Clamping (Max) @ Ipp:
- 53.3V
- Current - Peak Pulse (10/1000µs):
- 11.8A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 175°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMBflat
SMB6F33A FAQ
1.How can I place an order for SMB6F33A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMB6F33A 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 SMB6F33A reliable?
The price and inventory of SMB6F33A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMB6F33A is usually 5 days.
3.What payment methods are accepted for SMB6F33A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMB6F33A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMB6F33A?
SMB6F33A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMB6F33A 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 SMB6F33A?
For technical support, including SMB6F33A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMB6F33A requirements.
6.How does Aetrix verify that SMB6F33A is sourced from the original manufacturer or authorized distributors?
All SMB6F33A 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 SMB6F33A meets industry standards.
7.What is the process for return or replacement of SMB6F33A?
All SMB6F33A units undergo pre-shipment inspection (PSI). If there is an issue with SMB6F33A, 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 SMB6F33A part is unused and in its original packaging.
Return procedure for SMB6F33A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMB6F33A Tags
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