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STMicroelectronics SMA6F28AY
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- Part No.:
- SMA6F28AY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-221AC, SMA Flat Leads
- Datasheet:
-
SMA6F28AY.pdf
- Description:
- TVS DIODE 28VWM 45.4VC SMAFLAT
- Quantity:
- Payment:
- Shipping:
Inventory:6,401
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Product details
Overview
SMA6F28AY from STMicroelectronics is an AEC-Q101-qualified unidirectional automotive TVS diode in SMA Flat package, designed to clamp transient overvoltages up to 45.4 V (10/1000 µs) at 13.8 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 24 V automotive power lines.
For engineers reviewing the SMA6F28AY datasheet, SMA6F28AY pinout, SMA6F28AY application, or SMA6F28AY equivalent, this device is selected for high-reliability 24 V system surge suppression where low clamping voltage, thermal stability at Tj = 175 °C, and compliance with ISO 7637-2 Pulse 1/2a/3a are critical design requirements.
Technical Context
This TVS diode uses planar silicon technology to achieve stable breakdown behavior across -55 °C to +175 °C, with a typical breakdown voltage of 32.7 V at 1 mA and maximum clamping voltage of 45.4 V under 13.8 A (10/1000 µs). Its dynamic resistance is 0.804 Ω, enabling precise voltage limiting during fast transients.
The device complies with ISO 7637-2 Pulse 1 (-150 V), Pulse 2a (+112 V), Pulse 3a (-220 V), and Pulse 3b (+150 V) for 24 V battery systems, and meets IEC 61000-4-4 Level 4 (±4 kV) and ISO 10605 (±30 kV) ESD standards without derating at elevated temperatures.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Stand-off Voltage (VRM) | 28 V - Maximum continuous reverse operating voltage before conduction begins. |
| Breakdown Voltage (VBR) | 31.1–34.3 V @ 1 mA - Confirmed voltage threshold at which device enters avalanche conduction. |
| Clamping Voltage (VCL) | 45.4 V @ 13.8 A (10/1000 µs) - Actual voltage seen by protected circuit during worst-case surge. |
| Peak Pulse Power | 600 W (10/1000 µs) - Sustained energy handling capability at ambient temperature. |
| Leakage Current | 0.2 µA @ 25 °C, 1 µA @ 85 °C - Minimal parasitic loading on 24 V supply rail during normal operation. |
| Junction Temperature Range | -55 °C to +175 °C - Enables direct placement near hot engine-control electronics without thermal derating. |
| Package | SMA Flat (JEDEC DO-214AC) - 1 mm profile enables compact layout in space-constrained automotive ECUs. |
Pinout & Package
SMA6F28AY is housed in an SMA Flat (DO-214AC) surface-mount package measuring 2.90 × 5.35 × 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 return path | Connected to ground or low-impedance reference; carries full transient current during clamping. |
| Anode | Protected line input | Connected to 24 V supply rail or signal line; voltage is clamped relative to cathode potential. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive under-hood use with temperature cycling, humidity, and mechanical shock testing. |
| Low dynamic resistance | 0.804 Ω - Minimizes VCL rise under high-current surges, improving protection margin. |
| High-temperature reliability | Rated for continuous operation at Tj = 175 °C - Eliminates need for thermal derating in engine bay applications. |
| ESD robustness | ±30 kV contact/air discharge (ISO 10605, C = 330 pF/R = 330 Ω) - Survives assembly-line ESD events without degradation. |
| ISO 7637-2 compliance | Withstands Pulse 1 (-150 V), Pulse 2a (+112 V), Pulse 3a (-220 V), Pulse 3b (+150 V) - Certified for 24 V commercial vehicle power nets. |
Applications
| Engine Control Unit (ECU) Power Input | Body Control Module (BCM) LIN Bus Protection |
|---|---|
|
Use Scenario: 24 V battery feed to microcontroller power supply in diesel engine ECU exposed to load dump and alternator ripple. IC Role / Device Role: Primary transient voltage suppressor placed directly at DC-DC converter input. Use Value: Clamps ISO 7637-2 Pulse 1 (-150 V) to ≤45.4 V, preventing damage to 36 V-rated input capacitors and LDOs. |
Use Scenario: LIN bus transceiver interface in door module subjected to cable coupling and ESD during service. IC Role / Device Role: Unidirectional TVS on LIN line (VBAT-referenced) to suppress coupled transients and ESD. Use Value: Limits voltage excursion to <45.4 V during 13.8 A surge, preserving LIN PHY integrity without adding capacitance (>1 nF). |
| ADAS Camera Power Rail | Electric Power Steering (EPS) Motor Driver Supply |
|
Use Scenario: 24 V input to image sensor power management IC in front-facing camera exposed to ignition noise and jump-start spikes. IC Role / Device Role: First-stage clamping device upstream of filtering and regulation stages. Use Value: Maintains 0.2 µA leakage at 25 °C to avoid biasing errors in precision analog sensor supplies. |
Use Scenario: High-current 24 V supply to three-phase gate driver IC in EPS motor control unit. IC Role / Device Role: Secondary surge protector parallel to bulk capacitor, activated after primary MOV. Use Value: Delivers 600 W (10/1000 µs) clamping at 175 °C junction temperature, ensuring protection remains effective near MOSFET heatsinks. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMA6F28A | No AEC-Q101 qualification; same electrical specs but industrial-grade screening. | Not approved for automotive production; suitable only for non-safety-critical prototypes or aftermarket modules. | Select when cost sensitivity outweighs automotive qualification requirements. |
| SMCJ28A | Higher power rating (1500 W), larger SMC (DO-214AB) package, higher clamping voltage (49.9 V @ 30.1 A). | Better suited for 24 V systems requiring higher surge margin but with less board space constraint. | Choose when system-level testing shows 600 W insufficient and PCB layout allows larger footprint. |
Compared with SMA6F28A and SMCJ28A, SMA6F28AY uniquely balances AEC-Q101 compliance, 1 mm profile, and precise 45.4 V clamping-making it optimal for volume automotive ECUs where qualification, size, and voltage margin are simultaneously constrained.
Availability
SMA6F28AY is available at Aetrix Electronics and suitable for engine control units, body control modules, ADAS camera power rails, and electric power steering systems requiring stable component supply with full automotive qualification traceability.
Supply support for SMA6F28AY 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 broad manufacturing and R&D infrastructure.
SMA6FxxAY belongs to ST's Transil™ automotive TVS family, engineered specifically for ISO 7637-2 and ISO 10605 compliance in 12 V/24 V vehicle networks-prioritizing thermal stability, low leakage, and repeatable clamping performance under harsh conditions.
FAQ
What is the maximum clamping voltage of SMA6F28AY under a 10/1000 µs surge?
The maximum clamping voltage is 45.4 V at 13.8 A peak pulse current for a 10/1000 µs waveform, measured at Tamb = 25 °C per Table 2 of DS12477 Rev 3. This value increases linearly with junction temperature using the αT coefficient of 9.8 × 10−4/°C.
Does SMA6F28AY meet ISO 7637-2 Pulse 3b requirements for 24 V systems?
Yes-SMA6F28AY is validated to withstand ISO 7637-2 Pulse 3b (+150 V) without failure. Its 28 V stand-off voltage and 45.4 V clamping ensure the protected circuit sees no more than 45.4 V during this transient, well below typical 36 V-rated downstream components.
Can SMA6F28AY be used in parallel for higher surge current handling?
No-parallel connection is not recommended due to mismatch in dynamic resistance (0.804 Ω) and VBR tolerance (±5%), which causes uneven current sharing and potential thermal runaway. Use a single higher-power device like SMCJ28A instead.
What is the marking code for SMA6F28AY on the device body?
The top-side marking is "6BUY", as specified in Table 6 of DS12477 Rev 3. This 4-character code identifies the part unambiguously on the SMA Flat package and matches ST's standard automotive marking convention for the SMA6FY series.
SMA6F28AY 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):
- 28V
- Voltage - Breakdown (Min):
- 31.1V
- Voltage - Clamping (Max) @ Ipp:
- 45.4V
- Current - Peak Pulse (10/1000µs):
- 13.8A
- 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
SMA6F28AY FAQ
1.How can I place an order for SMA6F28AY through Aetrix?
Please submit a Request for Quotation (RFQ) for SMA6F28AY 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 SMA6F28AY reliable?
The price and inventory of SMA6F28AY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMA6F28AY is usually 5 days.
3.What payment methods are accepted for SMA6F28AY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMA6F28AY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMA6F28AY?
SMA6F28AY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMA6F28AY 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 SMA6F28AY?
For technical support, including SMA6F28AY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMA6F28AY requirements.
6.How does Aetrix verify that SMA6F28AY is sourced from the original manufacturer or authorized distributors?
All SMA6F28AY 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 SMA6F28AY meets industry standards.
7.What is the process for return or replacement of SMA6F28AY?
All SMA6F28AY units undergo pre-shipment inspection (PSI). If there is an issue with SMA6F28AY, 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 SMA6F28AY part is unused and in its original packaging.
Return procedure for SMA6F28AY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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