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STMicroelectronics SMA6F85AY
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- Part No.:
- SMA6F85AY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-221AC, SMA Flat Leads
- Datasheet:
-
SMA6F85AY.pdf
- Description:
- TVS DIODE 85VWM 137VC SMAFLAT
- Quantity:
- Payment:
- Shipping:
Inventory:5,206
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Product details
Overview
SMA6F85AY from STMicroelectronics is an AEC-Q101-qualified unidirectional automotive TVS diode in SMA Flat package, designed to clamp transient overvoltages up to 137 V (10/1000 µs) at 4.6 A peak pulse current while maintaining low leakage (0.2 µA @ 25 °C) and operating up to 175 °C junction temperature. It delivers 600 W peak pulse power (10/1000 µs) and exceeds ISO 10605 ESD immunity (±30 kV contact/air) for robust protection of 12 V/24 V automotive power lines.
For engineers reviewing the SMA6F85AY datasheet, SMA6F85AY pinout, SMA6F85AY application, or SMA6F85AY equivalent, this device is selected for high-reliability surge suppression in battery-supplied ECUs, LIN/CAN node interfaces, and body control modules where stand-off voltage (VRM = 85 V), clamping performance (VCL = 137 V @ IPP = 4.6 A), thermal stability (Tj max = 175 °C), and flat-package board space constraints are critical.
Technical Context
This TVS diode uses planar silicon technology to achieve low dynamic resistance (RD = 3.29 Ω) and stable clamping across temperature (αT = 10.6 × 10⁻⁴ /°C), enabling predictable voltage limiting during ISO 7637-2 pulses (Pulse 1: −150 V; Pulse 2a: +112 V; Pulse 3a: −220 V; Pulse 3b: +150 V). Its unidirectional configuration supports DC-biased lines with reverse standoff capability only.
It complies with IEC 61000-4-4 Level 4 (±4 kV), ISO 10605 (C = 150/330 pF, R = 330 Ω), and UL94 V0 flammability rating. The SMA Flat package (1.0 mm height, JEDEC registered outline) ensures compatibility with automated SMT assembly and meets J-STD-020 MSL Level 1 handling requirements.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Stand-off Voltage (VRM) | 85 V - Maximum continuous reverse operating voltage before breakdown; sets minimum system operating margin above 24 V nominal bus. |
| Breakdown Voltage (VBR) | 95–105 V @ 1 mA - Tight tolerance (±5.3%) ensures consistent turn-on threshold across production lots and temperature. |
| Clamping Voltage (VCL) | 137 V @ 4.6 A (10/1000 µs) - Limits transient voltage seen by downstream ICs; enables safe operation with 150 V-rated components. |
| Peak Pulse Power (PPP) | 600 W (10/1000 µs) - Sustains high-energy transients without failure; derates to 400 W at Tj = 175 °C per Figure 3. |
| Leakage Current (IRM) | 0.2 µA @ 25 °C, 1 µA @ 85 °C - Minimizes standby power loss and avoids false triggering in low-current sensor circuits. |
| Junction Temperature Range | −55 to +175 °C - Supports under-hood deployment in engine control units and transmission control modules. |
| Dynamic Resistance (RD) | 3.29 Ω - Low impedance limits voltage overshoot during fast-rising transients (e.g., ISO 7637-2 Pulse 3b). |
Pinout & Package
SMA6F85AY is housed in a surface-mount SMA Flat package (JEDEC DO-214AC), measuring 2.90 mm × 5.35 mm × 1.10 mm (L × W × H), with matte tin-plated leads and IPC7531-compliant footprint. The package is MSL Level 1 and rated for 260 °C peak soldering temperature (10 s).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (marked band) | Transient voltage clamp output | Connected to protected line; sinks surge current to ground when voltage exceeds VRM. |
| Anode | Reference/ground return path | Must be connected to low-impedance chassis or power ground to ensure effective clamping and thermal dissipation. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive use including temperature cycling, humidity bias, and mechanical shock per stress test requirements. |
| ISO 7637-2 compliance | Withstands defined load-dump and switching transients (Pulse 1, 2a, 3a, 3b) without degradation or parametric shift. |
| Low-profile SMA Flat package | 1.0 mm max height enables placement in space-constrained modules such as door modules and seat controllers. |
| High-temperature reliability | Stable clamping and leakage behavior up to 175 °C junction temperature ensures long-term operation in under-hood environments. |
| ESD robustness | Exceeds ±30 kV contact/air discharge (ISO 10605, C = 330 pF/R = 330 Ω), eliminating need for additional ESD protection stages. |
Applications
| Engine Control Unit (ECU) Power Input | CAN Transceiver Protection |
|---|---|
|
Use Scenario: 12 V battery feed to microcontroller power supply in gasoline/diesel engine management systems. IC Role / Device Role / Timing Role: Unidirectional TVS clamps load-dump transients (ISO 7637-2 Pulse 2a: +112 V) and alternator-induced spikes. Use Value: Prevents damage to 5 V/3.3 V LDO regulators and MCU power rails by limiting input voltage to ≤137 V during 4.6 A surges. |
Use Scenario: CAN_H/CAN_L signal lines connecting ECU to gateway or body domain controller. IC Role / Device Role / Timing Role: Clamps ESD events (±30 kV) and coupled transients from adjacent power lines without distorting signal integrity. Use Value: Maintains <1 ns response time and <10 pF junction capacitance to avoid CAN FD bit-rate degradation (up to 5 Mbps). |
| Body Control Module (BCM) LIN Bus | Automotive Lighting Driver Input |
|
Use Scenario: LIN physical layer interface in door modules, mirror controls, or seat position sensors. IC Role / Device Role / Timing Role: Protects LIN transceiver against battery reversal, jump-start surges, and ESD in low-speed serial networks. Use Value: Ensures reliable communication during ±220 V Pulse 3a transients while drawing <0.2 µA leakage to preserve sleep-mode current budget. |
Use Scenario: 24 V input stage of LED headlamp driver ICs subjected to load-dump and inductive kickback. IC Role / Device Role / Timing Role: Absorbs 600 W (10/1000 µs) energy from relay coil de-energization and alternator regulation faults. Use Value: Enables single-device protection without external series resistors or RC snubbers, reducing BOM count and PCB area. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMA6F85A | Same electrical specs but non-automotive grade; lacks AEC-Q101 qualification and ISO 7637-2 validation. | Restricted to non-safety-critical consumer or industrial power supplies; not approved for automotive ECU use. | Select only if AEC-Q101 and automotive transient standards are not required. |
| SMCJ85A | Higher PPP (1500 W), larger SMC package (7.1 mm × 6.2 mm × 2.6 mm), higher VCL (139 V @ 10.9 A). | Better suited for high-energy 48 V mild-hybrid systems; incompatible with space-constrained SMA footprints. | Choose when surge energy exceeds 600 W or PCB layout allows larger package. |
Compared with SMA6F85A and SMCJ85A, SMA6F85AY uniquely balances AEC-Q101 compliance, SMA footprint constraints, and precise 85 V stand-off for 24 V automotive systems-making it optimal for volume ECU designs where qualification, size, and cost must coexist.
Availability
SMA6F85AY is available at Aetrix Electronics and suitable for engine control units, body control modules, lighting drivers, and CAN/LIN node protection requiring stable component supply across automotive production lifecycles.
Supply support for SMA6F85AY 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, delivering intelligent power, sensing, and control solutions for automotive, industrial, and consumer markets.
SMA6FxxAY belongs to ST's Automotive Transil™ TVS portfolio, engineered specifically for ISO 7637-2 and ISO 10605 compliance in harsh automotive environments-prioritizing reliability, thermal resilience, and footprint efficiency.
FAQ
What is the maximum clamping voltage of SMA6F85AY under a 10/1000 µs surge?
The maximum clamping voltage is 137 V at 4.6 A peak pulse current (10/1000 µs), measured at Tj = 25 °C. This value increases with junction temperature at a coefficient of 10.6 × 10⁻⁴ /°C, reaching approximately 142 V at Tj = 125 °C per the VCL vs. Tj formula in the datasheet.
Is SMA6F85AY compatible with lead-free reflow soldering processes?
Yes-SMA6F85AY is qualified for lead-free reflow per J-STD-020 MSL Level 1, with a peak temperature rating of 260 °C for 10 seconds. ST recommends using the reflow profile shown in Figure 24 (DS12477 Rev 3), with ramp rates ≤3 °C/s and a 60–90 second dwell above 217 °C.
How does SMA6F85AY differ from SMA6F85A in terms of automotive qualification?
SMA6F85AY is AEC-Q101 qualified and validated for ISO 7637-2 (Pulse 1, 2a, 3a, 3b) and ISO 10605 testing, whereas SMA6F85A is a commercial-grade variant lacking automotive stress screening and transient compliance documentation. Only SMA6F85AY is approved for safety-critical ECU applications.
Can SMA6F85AY be used on 48 V automotive systems?
No-its 85 V stand-off voltage (VRM) and 137 V clamping voltage are optimized for 12 V/24 V battery architectures. For 48 V systems, ST recommends higher-voltage variants like SMA6F130AY (VRM = 130 V) or SMCJ130A, which provide appropriate margin above nominal bus voltage and meet ISO 7637-2 Pulse 1 (−150 V) requirements.
SMA6F85AY Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-221AC, SMA Flat Leads
- Series:
- SMA6F
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 85V (Max)
- 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:
- SMAflat
SMA6F85AY FAQ
1.How can I place an order for SMA6F85AY through Aetrix?
Please submit a Request for Quotation (RFQ) for SMA6F85AY 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 SMA6F85AY reliable?
The price and inventory of SMA6F85AY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMA6F85AY is usually 5 days.
3.What payment methods are accepted for SMA6F85AY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMA6F85AY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMA6F85AY?
SMA6F85AY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMA6F85AY 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 SMA6F85AY?
For technical support, including SMA6F85AY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMA6F85AY requirements.
6.How does Aetrix verify that SMA6F85AY is sourced from the original manufacturer or authorized distributors?
All SMA6F85AY 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 SMA6F85AY meets industry standards.
7.What is the process for return or replacement of SMA6F85AY?
All SMA6F85AY units undergo pre-shipment inspection (PSI). If there is an issue with SMA6F85AY, 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 SMA6F85AY part is unused and in its original packaging.
Return procedure for SMA6F85AY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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