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STMicroelectronics SMA6T28AY
- Part No.:
- SMA6T28AY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMA6T28AY.pdf
- Description:
- TVS DIODE 24VWM 44.3VC SMA
- Quantity:
- Payment:
- Shipping:
Inventory:3,171
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Product details
Overview
SMA6T28AY from STMicroelectronics is a unidirectional 600 W automotive-grade transient voltage suppression (TVS) diode in SMA package, designed for ISO 7637-2 pulse protection and ESD immunity per ISO 10605. It features a 28.1 V nominal breakdown voltage (VBR), 37.8 V maximum clamping voltage (VCL) at 16 A (10/1000 µs), and ≤0.2 µA leakage at 25 °C - enabling robust surge protection in 12 V/24 V automotive power rails.
For engineers reviewing the SMA6T28AY datasheet, SMA6T28AY pinout, SMA6T28AY application, or SMA6T28AY equivalent, key selection criteria include clamping performance under ISO 7637-2 Pulse 1 (–150 V), junction temperature derating up to +150 °C, low dynamic resistance (0.516 Ω), and AEC-Q101 qualification for under-hood deployment.
Technical Context
This TVS diode uses planar silicon technology to achieve stable VBR with ±5% tolerance and low temperature coefficient (αT = 9.6 × 10−4/°C), ensuring predictable clamping across –55 °C to +150 °C operating range. Its unidirectional configuration provides forward conduction path for reverse-polarity fault protection while blocking normal forward bias.
The device meets IEC 61000-4-4 Level 4 (4 kV), ISO 10605 (30 kV air/contact discharge), and ISO 7637-2 Pulse 1 (–150 V), Pulse 2a (+112 V), Pulse 3a (–220 V), and Pulse 3b (+150 V) - making it suitable for CAN/LIN bus line protection, body control modules, and ADAS sensor power inputs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VBR (min/typ/max) | 24.0 / 26.7 / 28.1 V at IBR = 1 mA - defines precise turn-on threshold for overvoltage detection |
| VCL (10/1000 µs) | 37.8 V at IPP = 16 A - limits downstream IC voltage during 10/1000 µs transients |
| Peak Pulse Power | 600 W (10/1000 µs), 4 kW (8/20 µs) - supports high-energy surge absorption without thermal runaway |
| IR (leakage) | ≤0.2 µA at VRM = 22.8 V, 25 °C - ensures minimal standby current in always-on vehicle networks |
| Tj max | +150 °C - enables placement near heat sources (e.g., engine ECUs) without derating |
| Dynamic Resistance | 0.516 Ω - determines VCL rise slope (ΔV = RD × ΔI) under fast surges |
| AEC-Q101 Qualified | Validated for automotive reliability including temperature cycling, HTRB, and ESD stress - required for Tier-1 production |
Pinout & Package
Package: SMA (DO-214AC), JEDEC registered outline, matte tin-plated leads, MSL Level 1, footprint per IPC7531.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (marked band) | Surge current sink | Connected to protected line; conducts during overvoltage to clamp against ground |
| Anode | Reference node | Typically tied to system ground or low-impedance return path for bidirectional energy dissipation |
Key Features
| Feature | Design Value |
|---|---|
| ISO 7637-2 Pulse Compliance | Validated for Pulse 1 (–150 V), Pulse 2a (+112 V), Pulse 3a (–220 V), Pulse 3b (+150 V) - covers all battery-line surge events in 12 V systems |
| Low-Temp Coefficient Clamping | αT = 9.6 × 10−4/°C - maintains <±10% VCL shift from –40 °C to +125 °C for stable protection margin |
| ESD Robustness | 30 kV contact/air discharge (ISO 10605, C = 150 pF/R = 330 Ω) - exceeds automotive infotainment and sensor interface requirements |
| Thermal Stability | Rth(j-a) = ~100 °C/W on 1 cm² FR4 copper - enables reliable operation without heatsink in space-constrained modules |
| Automotive Process Control | AEC-Q101 qualified with wafer-level burn-in and lot traceability - satisfies PPAP documentation for OEM sourcing |
Applications
| Engine Control Unit (ECU) Power Input | Body Control Module (BCM) LIN Bus |
|---|---|
Use Scenario: Protects 12 V supply rail of gasoline/diesel engine ECUs against load dump and alternator ripple. IC Role / Device Role / Timing Role: Unidirectional TVS placed between battery feed and LDO input to clamp transients before regulation. Use Value: Withstands ISO 7637-2 Pulse 1 (–150 V) and Pulse 2a (+112 V) without degradation, preserving MCU uptime during cranking. |
Use Scenario: Shields LIN transceiver PHY layer from ESD and coupled noise in door module wiring harnesses. IC Role / Device Role / Timing Role: Low-capacitance TVS connected between LIN line and ground to suppress fast transients without distorting 19.2 kbps signaling. Use Value: 0.2 µA leakage and 37.8 V clamping ensure signal integrity and prevent false wake-up in sleep-mode LIN nodes. |
| ADAS Camera Power Supply | Infotainment Display Backlight Driver |
Use Scenario: Guards 5 V/3.3 V camera sensor power rails against hot-swap and cable discharge events. IC Role / Device Role / Timing Role: TVS placed at connector entry point to absorb ISO 10605 ESD strikes before DC-DC converter input. Use Value: 30 kV air/contact ESD rating prevents latch-up in CMOS image sensors, eliminating field returns due to pixel corruption. |
Use Scenario: Protects LED driver ICs from transients induced by PWM dimming switching in TFT display assemblies. IC Role / Device Role / Timing Role: Unidirectional TVS on boost converter output to clamp inductive kickback from LED string current regulation. Use Value: 600 W peak power rating sustains repeated 10/1000 µs surges during factory test cycles without parameter drift. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMA6T28A | No AEC-Q101 qualification; identical electrical specs and package | Not approved for automotive production; acceptable for industrial prototypes | Select only if AEC-Q101 compliance is not required and cost sensitivity outweighs qualification risk |
| SMCJ28A | Higher 1500 W peak power (10/1000 µs); DO-214AB package (larger footprint) | Better suited for 24 V commercial truck systems with higher load-dump energy | Choose when surge energy exceeds 600 W or board layout allows larger SMC package |
Compared with SMA6T28A, SMA6T28AY adds AEC-Q101 validation for production use, while SMCJ28A trades smaller size for higher power handling - making SMA6T28AY optimal for space-constrained, qualified 12 V automotive modules where 600 W suffices.
Availability
SMA6T28AY is available at Aetrix Electronics and suitable for automotive power rail protection, LIN/CAN bus interface hardening, ADAS sensor power conditioning, and infotainment ESD shielding requiring stable component supply across multi-year vehicle programs.
Supply support for SMA6T28AY 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 automotive, industrial, and power management solutions with vertical manufacturing and long-term product longevity commitments.
SMA6TY belongs to ST's Transil™ TVS portfolio, engineered specifically for automotive-grade transient suppression - balancing low leakage, tight VBR tolerance, and AEC-Q101 reliability in compact surface-mount packages.
FAQ
What is the maximum clamping voltage of SMA6T28AY under a 10/1000 µs surge?
The maximum clamping voltage is 37.8 V at 16 A peak pulse current (10/1000 µs), measured at Tj = 25 °C. This value increases with junction temperature using αT = 9.6 × 10−4/°C, reaching ~41.2 V at +125 °C - critical for verifying downstream IC overvoltage margins.
Can SMA6T28AY be used in bidirectional configurations?
No - SMA6T28AY is unidirectional (anode-cathode polarity). For bidirectional protection, ST offers SMA6T28CAY, which has symmetrical clamping in both directions and identical VBR and VCL ratings. Mixing unidirectional and bidirectional types risks incorrect surge routing.
How does the 0.2 µA leakage current impact low-power automotive modules?
At 22.8 V reverse standoff and 25 °C, 0.2 µA leakage contributes negligible current draw - less than 0.05 mW power loss - making it ideal for always-on domains like telematics or alarm systems where battery drain must stay below 10 µA total.
Is the SMA package compatible with standard reflow profiles for lead-free assembly?
Yes - SMA6T28AY is rated MSL Level 1 and supports JEDEC J-STD-020 reflow profiles, including peak temperatures up to 260 °C for 10 seconds. Matte tin plating ensures solderability without whisker growth, validated per JESD201 Class 2.
SMA6T28AY Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AC, SMA
- Series:
- SMA6TY, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 24V
- Voltage - Breakdown (Min):
- 26.7V
- Voltage - Clamping (Max) @ Ipp:
- 44.3V
- Current - Peak Pulse (10/1000µs):
- 80A (8/20µs)
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMA6T28AY FAQ
1.How can I place an order for SMA6T28AY through Aetrix?
Please submit a Request for Quotation (RFQ) for SMA6T28AY 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 SMA6T28AY reliable?
The price and inventory of SMA6T28AY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMA6T28AY is usually 5 days.
3.What payment methods are accepted for SMA6T28AY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMA6T28AY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMA6T28AY?
SMA6T28AY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMA6T28AY 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 SMA6T28AY?
For technical support, including SMA6T28AY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMA6T28AY requirements.
6.How does Aetrix verify that SMA6T28AY is sourced from the original manufacturer or authorized distributors?
All SMA6T28AY 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 SMA6T28AY meets industry standards.
7.What is the process for return or replacement of SMA6T28AY?
All SMA6T28AY units undergo pre-shipment inspection (PSI). If there is an issue with SMA6T28AY, 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 SMA6T28AY part is unused and in its original packaging.
Return procedure for SMA6T28AY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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