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STMicroelectronics SMB6F85AY
- Part No.:
- SMB6F85AY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-221AA, SMB Flat Leads
- Datasheet:
-
SMB6F85AY.pdf
- Description:
- TVS DIODE 85VWM 137VC SMBFLAT
- Quantity:
- Payment:
- Shipping:
Inventory:9,752
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Product details
Overview
SMB6F85AY from STMicroelectronics is an AEC-Q101-qualified unidirectional automotive TVS diode in SMB Flat package, designed to clamp transient overvoltages up to 137 V (10/1000 µs) with 4.6 A peak pulse current and 7.17 Ω dynamic resistance at 25 °C. It delivers 600 W peak pulse power (10/1000 µs), operates up to 175 °C junction temperature, and protects 12 V/24 V automotive circuits against ISO 7637-2 pulses (Pulse 1, 2a, 3a, 3b) and ISO 10605 ESD events.
For engineers reviewing the SMB6F85AY datasheet, SMB6F85AY pinout, SMB6F85AY application, or SMB6F85AY equivalent, this device is selected for high-reliability automotive power line protection where low leakage (0.2 µA @ 25 °C), flat 1 mm profile, and robust 30 kV ESD immunity are critical design requirements.
Technical Context
This unidirectional TVS diode uses planar silicon technology to achieve low leakage current (≤1 µA @ 85 °C) and stable clamping performance across –55 °C to +175 °C junction temperature range. Its 85 V stand-off voltage (VRM) and 100 V minimum breakdown voltage (VBR) enable reliable operation on 24 V battery systems while avoiding false triggering during load dump transients.
The SMB6F85AY exhibits a 10.6 × 10⁻⁴ /°C temperature coefficient (αT) for VBR and VCL, ensuring predictable voltage drift under thermal stress. Its dynamic resistance of 7.17 Ω (10/1000 µs) and 22.5 Ω (8/20 µs) directly determines clamping voltage rise under surge current, supporting precise overvoltage margining in CAN, LIN, and sensor supply lines.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Stand-off Voltage (VRM) | 85 V - Blocks normal 24 V system operation without conduction; sets minimum surge threshold before clamping. |
| Breakdown Voltage (VBR) | 95–105 V @ 1 mA - Defines precise turn-on point; ensures clamping initiates before downstream IC damage thresholds. |
| Clamping Voltage (VCL) | 137 V @ 4.6 A (10/1000 µs) - Maximum voltage seen by protected circuit during worst-case surge; enables safe margin vs. 150 V IC absolute max ratings. |
| Peak Pulse Power | 600 W (10/1000 µs), 4 kW (8/20 µs) - Sustains high-energy transients per ISO 7637-2 Pulse 1 (–150 V) and Pulse 3b (+150 V) without failure. |
| Leakage Current | 0.2 µA @ 25 °C, 1 µA @ 85 °C - Minimizes standby power loss and avoids false wake-up in always-on automotive modules. |
| Junction Temperature Range | –55 °C to +175 °C - Supports under-hood placement near engines and transmission control units without derating. |
| ESD Withstand | ±30 kV (air/contact, ISO 10605, C = 150 pF/R = 330 Ω) - Exceeds automotive ESD immunity requirement (Level 4) for infotainment and body control interfaces. |
Pinout & Package
SMB6F85AY is housed in an SMB Flat surface-mount package (JEDEC DO-214AA), measuring 3.95 mm × 5.60 mm × 1.10 mm (L × W × H), with 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 (e.g., CAN_H); conducts transient energy to ground when voltage exceeds VBR. |
| Anode | Reference Node | Connected to system ground or low-impedance return path; completes clamping loop with minimal inductance. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive use across temperature, humidity, and mechanical shock profiles - eliminates requalification effort for Tier 1 suppliers. |
| Flat 1 mm profile | Enables PCB height clearance in space-constrained modules (e.g., ADAS camera housings, seat control ECUs) without compromising thermal dissipation. |
| Low dynamic resistance (7.17 Ω) | Reduces clamping voltage overshoot during fast transients, improving protection margin for 120 V-rated CAN transceivers and microcontrollers. |
| High-temperature leakage stability | 1 µA @ 85 °C ensures no measurable current injection into sensor reference rails or analog front-ends under hood thermal conditions. |
| ISO 7637-2 compliance | Withstands Pulse 1 (–150 V), Pulse 2a (+112 V), Pulse 3a (–220 V), and Pulse 3b (+150 V) - covers all standard automotive power line disturbance waveforms. |
Applications
| Body Control Module (BCM) | Engine Control Unit (ECU) Power Input |
|---|---|
Use Scenario: Protects 24 V supply rail feeding microcontroller, LIN transceivers, and relay drivers from load dump and jump-start surges. IC Role / Device Role / Timing Role: Unidirectional TVS placed between battery input and DC-DC converter input to clamp transients before regulation stage. Use Value: Prevents latch-up or permanent damage to 5 V/3.3 V regulators and MCU I/O pins during ISO 7637-2 Pulse 1 (–150 V) events. |
Use Scenario: Shields main 12 V/24 V power entry of engine ECU against alternator-induced load dump and ignition coil switching noise. IC Role / Device Role / Timing Role: Primary overvoltage clamp on main power rail, positioned upstream of fuse and reverse-polarity protection MOSFET. Use Value: Limits clamped voltage to 137 V during 600 W surges, maintaining safe margin below 150 V absolute maximum rating of power management ICs. |
| CAN Transceiver Protection | ADAS Camera Power Line |
Use Scenario: Safeguards high-speed CAN FD transceiver (e.g., TJA1044) on vehicle network backbone from ESD and coupled transients. IC Role / Device Role / Timing Role: Bidirectional protection not required; unidirectional SMB6F85AY used on CAN_H line referenced to ground to suppress positive-going spikes only. Use Value: Achieves ±30 kV ESD immunity (ISO 10605) while adding <1 pF capacitance - preserves signal integrity up to 5 Mbps CAN FD data rates. |
Use Scenario: Secures 12 V power input to rear-view or surround-view camera module mounted near exhaust or engine bay. IC Role / Device Role / Timing Role: First-line transient suppressor on camera power trace, placed immediately after connector to intercept external surges before LDO regulator. Use Value: Operates reliably at 175 °C junction temperature, enabling direct mounting on compact camera PCBs without thermal derating. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional automotive TVS applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ85A | Same SMB package, but rated for 600 W (10/1000 µs); VBR = 94.4–104.9 V; higher leakage (1 µA @ 25 °C). | Lacks AEC-Q101 qualification; not validated for automotive temperature cycling or humidity testing. | Select SMBJ85A only for non-automotive industrial applications where qualification is not required. |
| SMCJ85A | Larger SMC package (7.11 mm × 6.22 mm); same 85 V VRM; 1500 W peak power; VCL = 137 V @ 10.3 A. | Higher surge capacity suits heavy-duty truck 24 V systems with larger energy transients; footprint incompatible with SMB layout. | Choose SMCJ85A when surge energy exceeds 600 W and board space allows larger package; not drop-in compatible. |
Compared with SMBJ85A, SMB6F85AY provides certified automotive reliability and lower leakage; compared with SMCJ85A, it trades surge headroom for space savings and thermal efficiency in compact modules.
Availability
SMB6F85AY is available at Aetrix Electronics and suitable for automotive body electronics, powertrain control units, and ADAS camera systems requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for SMB6F85AY 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-grade analog, power, and microcontroller solutions with vertical manufacturing and AEC-Q100/Q101 validation capabilities.
The SMB6FxxAY series belongs to ST's automotive transient voltage suppression portfolio, engineered specifically for ISO 7637-2 and ISO 10605 compliance in 12 V/24 V vehicle networks - targeting high-reliability power line and data line protection.
FAQ
What is the maximum clamping voltage of SMB6F85AY under a 10/1000 µs surge?
The SMB6F85AY clamps to a maximum of 137 V when subjected to a 4.6 A 10/1000 µs surge current, as specified in Table 2 of DS12412 Rev 1. This value is measured at 25 °C ambient and represents the upper limit of voltage imposed on protected circuitry during standardized transient events.
Does SMB6F85AY require a heatsink for operation at 175 °C junction temperature?
No heatsink is required: the SMB6F85AY is rated for continuous operation up to 175 °C junction temperature with its SMB Flat package, provided the PCB uses the recommended IPC7531-compliant footprint with ≥1.2 cm² copper area per lead (per Figure 11). Thermal resistance drops to ~3.5 °C/W under those conditions.
Can SMB6F85AY be used on bidirectional signal lines like CAN bus?
No - SMB6F85AY is unidirectional and only protects against positive-going transients relative to ground. For bidirectional CAN lines, a symmetric dual-diode configuration or a dedicated bidirectional TVS (e.g., SMB6F85AY's counterpart SMB6F85CA) is required to suppress both positive and negative surges.
How does SMB6F85AY differ from generic SMBJ85A in automotive use?
SMB6F85AY is AEC-Q101 qualified with verified performance across –55 °C to +175 °C, low leakage (0.2 µA @ 25 °C), and full ISO 7637-2/Pulse 3b compliance; SMBJ85A lacks automotive qualification, has higher leakage, and is not tested to automotive surge standards - making it unsuitable for production vehicle ECUs.
SMB6F85AY Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-221AA, SMB Flat Leads
- Series:
- SMB6FxxAY
- 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:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 175°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMBflat
SMB6F85AY FAQ
1.How can I place an order for SMB6F85AY through Aetrix?
Please submit a Request for Quotation (RFQ) for SMB6F85AY 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 SMB6F85AY reliable?
The price and inventory of SMB6F85AY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMB6F85AY is usually 5 days.
3.What payment methods are accepted for SMB6F85AY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMB6F85AY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMB6F85AY?
SMB6F85AY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMB6F85AY 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 SMB6F85AY?
For technical support, including SMB6F85AY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMB6F85AY requirements.
6.How does Aetrix verify that SMB6F85AY is sourced from the original manufacturer or authorized distributors?
All SMB6F85AY 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 SMB6F85AY meets industry standards.
7.What is the process for return or replacement of SMB6F85AY?
All SMB6F85AY units undergo pre-shipment inspection (PSI). If there is an issue with SMB6F85AY, 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 SMB6F85AY part is unused and in its original packaging.
Return procedure for SMB6F85AY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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