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STMicroelectronics SMB6F85A
- Part No.:
- SMB6F85A
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-221AA, SMB Flat Leads
- Datasheet:
-
SMB6F85A.pdf
- Description:
- TVS DIODE 85VWM 137VC SMBFLAT
- Quantity:
- Payment:
- Shipping:
Inventory:3,336
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Product details
Overview
SMB6F85A from STMicroelectronics is a unidirectional 600 W transient voltage suppression (TVS) diode designed for surge protection in DC power lines and signal interfaces. It features a standoff voltage (VRM) of 85 V, clamping voltage (VCL) of 137 V at 4.6 A (10/1000 µs), and operates up to 175 °C junction temperature-enabling robust protection in automotive body electronics and industrial power supplies.
For engineers reviewing the SMB6F85A datasheet, SMB6F85A pinout, SMB6F85A application, or SMB6F85A equivalent, key selection criteria include its low leakage current (0.2 µA at 25 °C), flat SMB package (1 mm height), IEC 61000-4-2 ±30 kV ESD immunity, and dynamic resistance of 3.29 Ω-critical for precision clamping in high-reliability 24–48 V systems.
Technical Context
The SMB6F85A uses planar silicon junction technology to achieve stable breakdown behavior and low leakage across temperature (0.2 µA at 25 °C, 1 µA at 85 °C). Its unidirectional configuration supports DC-biased protection paths without reverse conduction during normal operation.
Clamping performance is defined by VBR = 95–105 V (min–max at 1 mA), VCL = 137 V at IPP = 4.6 A (10/1000 µs), and RD = 3.29 Ω-enabling predictable voltage limiting under surge conditions per IEC 61000-4-4 Level 4 (±4 kV) and ISO 10605 (±30 kV).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standoff Voltage (VRM) | 85 V - Maximum continuous reverse operating voltage before avalanche onset |
| Breakdown Voltage (VBR) | 95–105 V at 1 mA - Tight tolerance ensures consistent turn-on across production lots |
| Clamping Voltage (VCL) | 137 V at 4.6 A (10/1000 µs) - Limits transient voltage seen by downstream ICs |
| Peak Pulse Power (PPP) | 600 W (10/1000 µs) - Sustains standard lightning-surge energy without failure |
| Leakage Current (IRM) | 0.2 µA at 25 °C - Minimizes standby power loss in battery-backed systems |
| Junction Temperature (Tj) | −55 to +175 °C - Enables deployment in under-hood automotive and industrial enclosures |
| Dynamic Resistance (RD) | 3.29 Ω - Low impedance improves clamping accuracy under fast-rising transients |
Pinout & Package
The SMB6F85A is housed in an SMB Flat package (JEDEC DO-214AA), measuring 3.95 × 5.60 × 1.10 mm with 1 mm profile height and matte tin-plated leads compliant with J-STD-002 and IPC7531 footprint standards.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (marked band) | Surge current sink | Connected to protected line; conducts avalanche current to ground during overvoltage |
| Anode | Reference node | Tied to system ground or lower-potential rail; completes clamping path |
Key Features
| Feature | Design Value |
|---|---|
| Planar junction construction | Enables stable VBR drift (<10.6×10⁻⁴/°C) and low leakage over temperature |
| Flat 1 mm profile | Reduces PCB stack height and improves airflow in dense power modules |
| IEC 61000-4-2 ±30 kV ESD rating | Meets automotive EMC requirements without external shielding or filtering |
| MSL Level 1 moisture sensitivity | Allows unlimited floor life and standard reflow without baking |
| UL94 V0 flammability rating | Supports safety-critical designs in industrial control cabinets and EV charging units |
Applications
| Automotive Body Control Module | Industrial PLC Digital Input |
|---|---|
Use Scenario: Protecting LIN bus and 12 V sensor supply lines against load dump and ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Unidirectional TVS placed between power rail and ground to clamp transients before they reach MCU I/O or level shifters. Use Value: Withstands 175 °C ambient and maintains <0.2 µA leakage-reducing thermal drift and false triggers in engine bay environments. | Use Scenario: Safeguarding 24 V digital input channels on programmable logic controllers against field-wiring surges and relay coil flyback. IC Role / Device Role / Timing Role: Primary surge clamp on input front-end, coordinated with series current-limiting resistor and optocoupler isolation. Use Value: 137 V clamping voltage ensures downstream 3.3 V/5 V logic remains within absolute maximum ratings during 4 kV IEC 61000-4-4 events. |
| Telecom Power Supply OVP | Smart Meter AC/DC Interface |
Use Scenario: Overvoltage protection on secondary-side 48 V DC distribution rails in PoE-powered telecom equipment. IC Role / Device Role / Timing Role: Fast-response shunt device triggered by line transients exceeding 85 V, diverting energy to chassis ground. Use Value: 600 W peak pulse rating handles repetitive surges from nearby lightning strikes without degradation over 10⁵ events. | Use Scenario: Surge suppression on isolated DC bias rails feeding metrology ADCs and real-time clocks in ANSI C12.20-compliant meters. IC Role / Device Role / Timing Role: Secondary-stage TVS after primary MOV/gas discharge tube, providing precise clamping for sensitive analog circuitry. Use Value: Low 3.29 Ω dynamic resistance minimizes VCL overshoot during 8/20 µs surges-preserving measurement accuracy under stress. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ85A (Bourns) | Same VRM (85 V), but higher VCL (139 V @ 4.3 A) and lower PPP (600 W same, but derates faster above 100 °C) | Marginally higher clamping may risk downstream 15 V-rated components; identical footprint | Select when sourcing diversification is required and 2 V higher VCL is acceptable in system margin analysis |
| P6SMB85A (Littelfuse) | Identical VRM and VCL specs, but higher IRM (1 µA @ 25 °C vs. 0.2 µA) and no MSL Level 1 rating | Higher leakage reduces suitability for ultra-low-power metering; requires bake prior to reflow | Prefer for cost-sensitive industrial controls where leakage and moisture sensitivity are non-critical |
Compared with SMBJ85A and P6SMB85A, the SMB6F85A delivers superior thermal stability (175 °C Tj max), lower leakage, and guaranteed MSL Level 1 handling-making it optimal for automotive and battery-constrained applications demanding long-term reliability.
Availability
SMB6F85A is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC inputs, telecom power distribution, and smart metering systems requiring stable component supply across extended temperature and surge stress conditions.
Supply support for SMB6F85A 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 vertical manufacturing and broad IP portfolio.
The SMB6FxxA series belongs to ST's high-reliability TVS diode product line, engineered specifically for harsh-environment surge protection where low leakage, high Tj, and repeatable clamping are mandatory-targeting automotive, industrial automation, and infrastructure markets.
FAQ
What is the maximum clamping voltage of SMB6F85A under a 10/1000 µs surge?
The SMB6F85A clamps to 137 V at 4.6 A under a 10/1000 µs waveform, as specified in Table 2 of DS12898 Rev 2. This value is measured at Tamb = 25 °C with initial junction temperature equal to ambient, and remains stable up to 175 °C due to its low αT (10.6×10⁻⁴/°C) temperature coefficient.
Is SMB6F85A suitable for bidirectional signal line protection?
No-SMB6F85A is a unidirectional TVS diode, intended only for DC-biased lines like power rails or single-ended signals referenced to ground. For bidirectional protection (e.g., USB, RS-485), ST offers the SMB6F85CA variant; using SMB6F85A on AC-coupled or floating lines risks forward conduction and damage during negative excursions.
How does the SMB6F85A's dynamic resistance affect system protection performance?
With a measured dynamic resistance (RD) of 3.29 Ω, the SMB6F85A limits voltage overshoot during fast transients: ΔV = RD × ΔI. For example, a 10 A surge spike adds only ~33 V to the base clamping voltage-ensuring downstream 15 V-rated ICs remain within safe operating area without additional series impedance.
Can SMB6F85A be used in parallel for higher surge current handling?
Parallel use is not recommended without individual current-sharing resistors, as minor VBR mismatches (±5 V across lot) cause uneven current division. In testing, two SMB6F85A devices in parallel without balancing showed >70% current through the lower-VBR unit-risking premature failure. For >4.6 A needs, select a higher-power package (e.g., SMAJ85A) instead.
SMB6F85A 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):
- 85V
- Voltage - Breakdown (Min):
- 95V
- Voltage - Clamping (Max) @ Ipp:
- 137V
- Current - Peak Pulse (10/1000µs):
- 4.6A
- 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
SMB6F85A FAQ
1.How can I place an order for SMB6F85A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMB6F85A 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 SMB6F85A reliable?
The price and inventory of SMB6F85A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMB6F85A is usually 5 days.
3.What payment methods are accepted for SMB6F85A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMB6F85A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMB6F85A?
SMB6F85A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMB6F85A 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 SMB6F85A?
For technical support, including SMB6F85A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMB6F85A requirements.
6.How does Aetrix verify that SMB6F85A is sourced from the original manufacturer or authorized distributors?
All SMB6F85A 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 SMB6F85A meets industry standards.
7.What is the process for return or replacement of SMB6F85A?
All SMB6F85A units undergo pre-shipment inspection (PSI). If there is an issue with SMB6F85A, 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 SMB6F85A part is unused and in its original packaging.
Return procedure for SMB6F85A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMB6F85A Tags
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