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STMicroelectronics SMA6F8.5A
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- Part No.:
- SMA6F8.5A
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-221AC, SMA Flat Leads
- Datasheet:
-
SMA6F8.5A.pdf
- Description:
- TVS DIODE 8.5VWM 14.4VC SMAFLAT
- Quantity:
- Payment:
- Shipping:
Inventory:9,640
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Product details
Overview
SMA6F8.5A from STMicroelectronics is a unidirectional 600 W transient voltage suppression (TVS) diode designed for primary-level surge protection in DC power rails and signal lines. It features a 8.5 V stand-off voltage (VRM), 9.4–10.4 V breakdown voltage (VBR), and clamps transients to ≤14.4 V at 41.7 A (10/1000 µs), enabling robust ESD and lightning surge immunity in industrial power supplies and automotive body electronics.
For engineers reviewing the SMA6F8.5A datasheet, SMA6F8.5A pinout, SMA6F8.5A application, or SMA6F8.5A equivalent, key selection criteria include its 1 µA leakage at VRM (85 °C), 175 °C max junction temperature, IEC 61000-4-2 Level 4 compliance (±25 kV contact / ±30 kV air), and SMA flat package thermal performance under high-reliability surge conditions.
Technical Context
The SMA6F8.5A operates as a planar-junction unidirectional TVS diode, leveraging avalanche breakdown to divert transient energy away from protected circuitry. Its low dynamic resistance (0.096 Ω at 10/1000 µs) ensures rapid clamping response with minimal voltage overshoot during fast-rising surges up to 4 kW (8/20 µs).
Thermal design is enabled by its 175 °C maximum junction temperature rating and compatibility with standard FR4 PCB footprints per IPC7531. The device maintains stable VBR and VCL across temperature via a +7.3 × 10⁻⁴/°C voltage temperature coefficient (αT), supporting operation in extended-temperature environments without derating recalculations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Stand-off Voltage (VRM) | 8.5 V - Maximum continuous reverse operating voltage before leakage exceeds 1 µA at 85 °C |
| Breakdown Voltage (VBR) | 9.4–10.4 V @ 1 mA - Confirmed avalanche onset range ensuring predictable turn-on during overvoltage events |
| Clamping Voltage (VCL) | 14.4 V @ 41.7 A (10/1000 µs) - Peak voltage seen by protected circuit during worst-case surge, limiting stress on downstream ICs |
| Peak Pulse Power (PPP) | 600 W (10/1000 µs) - Sustained surge energy handling capability at 25 °C ambient, de-rating to 400 W at 175 °C Tj |
| Leakage Current (IRM) | 1 µA @ VRM, 85 °C - Low standby current preserving battery life and minimizing false triggers in always-on systems |
| ESD Rating | ±25 kV contact / ±30 kV air (IEC 61000-4-2 Level 4) - Full compliance with industrial and automotive ESD immunity requirements |
| Junction Temperature Range | −55 to +175 °C - Enables deployment in under-hood automotive, industrial motor drives, and outdoor power equipment |
Pinout & Package
The SMA6F8.5A uses the industry-standard SMA (DO-214AC) flat package: 2.25–2.90 mm length, 5.00–5.35 mm width, 0.90–1.10 mm height, matte tin-plated leads, MSL Level 1, and JEDEC-compliant footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (marked band) | Surge return path | Connected to ground or low-impedance reference; carries full transient current during clamping |
| Anode | Protected line input | Connected to the line being safeguarded (e.g., 12 V rail, CAN H, RS-485 A); reverse-biased during normal operation |
Key Features
| Feature | Design Value |
|---|---|
| High-temperature reliability | Rated for continuous operation up to 175 °C junction temperature, supporting under-hood and high-power industrial use cases |
| Low-leakage planar junction | 1 µA IRM at 85 °C preserves signal integrity and reduces standby power loss in battery-backed systems |
| Fast clamping response | Dynamic resistance of 0.096 Ω (10/1000 µs) minimizes voltage overshoot during sub-microsecond transients |
| IEC 61000-4-2 Level 4 certified | Validated to withstand ±25 kV contact and ±30 kV air discharge without degradation or failure |
| Standardized SMA footprint | IPC7531-compliant layout enables drop-in replacement and automated assembly on existing production lines |
Applications
| Automotive Body Control Module (BCM) | Industrial 24 V DC Power Supply Input |
|---|---|
Use Scenario: Protecting microcontroller I/O and LIN bus transceivers from load-dump and jump-start surges in vehicle door modules. IC Role / Device Role / Timing Role: Primary unidirectional TVS clamp placed directly at connector entry point to limit voltage to <15 V during 12 V system transients. Use Value: Prevents latch-up and permanent damage to 5 V logic interfaces while maintaining <1 µA leakage at elevated cabin temperatures. | Use Scenario: Safeguarding PLC analog input channels and isolated DC-DC converter enable pins against induced surges from nearby relay switching. IC Role / Device Role / Timing Role: Standoff-rated TVS on 24 V supply rail upstream of LDO regulators, activated within nanoseconds of transient onset. Use Value: Clamps 41.7 A surges to ≤14.4 V, keeping downstream 3.3 V/5 V rails within absolute maximum ratings without requiring oversized filtering. |
| RS-485 Communication Port Protection | Smart Meter AC/DC Auxiliary Power Input |
Use Scenario: Shielding half-duplex RS-485 transceivers (e.g., SN65HVD72) from ESD and cable-induced surges in building automation networks. IC Role / Device Role / Timing Role: Bidirectional protection not required; unidirectional SMA6F8.5A placed on A/B lines referenced to local ground with low capacitance (<100 pF). Use Value: Delivers <15 V clamping at 40 A while adding negligible signal distortion due to planar junction's low dynamic impedance. | Use Scenario: Guarding auxiliary 12 V supply derived from rectified AC mains against lightning-induced surges entering through external connectors. IC Role / Device Role / Timing Role: First-stage TVS on secondary-side DC rail, coordinated with MOV and fuse to meet IEC 61000-4-5 Level 3 (2 kV line-earth) Use Value: Handles 600 W peak pulse energy at 25 °C and retains 400 W capability at 175 °C, ensuring long-term reliability in sealed meter enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ8.5A (Littelfuse) | Same SMA package, 8.5 V VRM, but higher VCL (15.0 V @ 38.2 A) and lower PPP (400 W) | Limited to lower-energy surge environments; unsuitable for 600 W IEC 61000-4-5 coordination | Select when cost sensitivity outweighs peak power margin and thermal derating headroom is available |
| P6SMB8.5A (ON Semiconductor) | Identical VRM and VBR range, but higher leakage (5 µA @ 85 °C) and no IEC 61000-4-2 Level 4 validation | Not recommended for automotive or medical-grade ESD-critical ports without additional testing | Acceptable for non-certified industrial controls where full ESD compliance is not mandated |
Compared with SMAJ8.5A and P6SMB8.5A, the SMA6F8.5A delivers superior thermal headroom (175 °C Tj), lower clamping voltage, and certified Level 4 ESD immunity-making it the preferred choice for safety-critical, high-reliability DC rail protection where long-term stability under thermal stress is mandatory.
Availability
SMA6F8.5A is available at Aetrix Electronics and suitable for automotive body electronics, industrial 24 V power supplies, RS-485 communication ports, and smart meter auxiliary power inputs requiring stable component supply across extended temperature ranges and multi-year production cycles.
Supply support for SMA6F8.5A 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 discrete technologies with over 40 years of TVS innovation.
The SMA6F series belongs to ST's Transil™ TVS portfolio, engineered specifically for high-reliability transient suppression in harsh environments where low leakage, high Tj, and certified ESD performance are non-negotiable design requirements.
FAQ
What is the maximum peak pulse current the SMA6F8.5A can handle at 10/1000 µs?
The SMA6F8.5A supports a peak pulse current of 41.7 A under the 10/1000 µs waveform at 25 °C ambient, with clamping voltage limited to 14.4 V. At 175 °C junction temperature, its peak pulse power drops to 400 W, corresponding to approximately 35.5 A under the same waveform-verified in ST's DS12564 Rev 3 datasheet Figure 5.
Does the SMA6F8.5A meet automotive AEC-Q200 stress test requirements?
No-the SMA6F8.5A is not AEC-Q200 qualified. While it operates up to 175 °C junction temperature and meets IEC 61000-4-2 Level 4, ST does not list it in their AEC-Q200 stress-tested product catalog. For automotive-grade qualification, consider ST's Automotive Transil™ series such as SMA6Q8.5A, which undergoes full AEC-Q200 temperature cycling, humidity bias, and mechanical shock testing.
Can the SMA6F8.5A be used in bidirectional configurations?
No-it is strictly unidirectional, as confirmed by its part number suffix "A" and electrical characterization (only reverse-biased leakage and breakdown specified). For bidirectional protection, ST offers the SMA6F8.5CA variant (dual-diode configuration), which provides symmetrical clamping for AC-coupled signals like USB or Ethernet data lines.
What is the recommended PCB footprint for optimal thermal performance?
ST specifies an IPC7531-compliant SMA footprint with minimum 0.5 cm² copper area per lead (per Figure 11 in DS12564 Rev 3). Using 35 µm Cu thickness on FR4, this achieves ~2.5 °C/W thermal resistance junction-to-ambient, critical for sustaining 600 W pulses without exceeding 175 °C Tj-verified in thermal impedance curves on page 5 of the datasheet.
SMA6F8.5A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-221AC, SMA Flat Leads
- Series:
- SMA6F, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 8.5V
- Voltage - Breakdown (Min):
- 9.4V
- Voltage - Clamping (Max) @ Ipp:
- 14.4V
- Current - Peak Pulse (10/1000µs):
- 41.7A
- 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:
- SMAflat
SMA6F8.5A FAQ
1.How can I place an order for SMA6F8.5A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMA6F8.5A 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 SMA6F8.5A reliable?
The price and inventory of SMA6F8.5A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMA6F8.5A is usually 5 days.
3.What payment methods are accepted for SMA6F8.5A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMA6F8.5A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMA6F8.5A?
SMA6F8.5A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMA6F8.5A 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 SMA6F8.5A?
For technical support, including SMA6F8.5A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMA6F8.5A requirements.
6.How does Aetrix verify that SMA6F8.5A is sourced from the original manufacturer or authorized distributors?
All SMA6F8.5A 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 SMA6F8.5A meets industry standards.
7.What is the process for return or replacement of SMA6F8.5A?
All SMA6F8.5A units undergo pre-shipment inspection (PSI). If there is an issue with SMA6F8.5A, 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 SMA6F8.5A part is unused and in its original packaging.
Return procedure for SMA6F8.5A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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