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STMicroelectronics SM4T23AY
- Part No.:
- SM4T23AY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SM4T23AY.pdf
- Description:
- TVS DIODE 20VWM 42.8VC SMA
- Quantity:
- Payment:
- Shipping:
Inventory:4,900
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Product details
Overview
SM4T23AY from STMicroelectronics is an AEC-Q101-qualified unidirectional automotive TVS diode in SMA package, designed to clamp transient surges up to 42.8 A (8/20 µs) with a clamping voltage of 32.4 V and stand-off voltage of 23.4 V (typical). It delivers 400 W peak pulse power (10/1000 µs), operates up to 150 °C junction temperature, and protects CAN, LIN, and sensor interfaces in 12 V automotive systems against ISO 7637-2 pulses and ISO 10605 ESD.
For engineers reviewing the SM4T23AY datasheet, SM4T23AY pinout, SM4T23AY application, or SM4T23AY equivalent, this device is selected for high-reliability 12 V battery rail protection where low leakage (<1 µA at 85 °C), tight VBR tolerance (±5%), and validated ISO 7637-2 Pulse 1/2a/3a/3b compliance are mandatory.
Technical Context
The SM4T23AY uses planar silicon technology to achieve low dynamic resistance (0.637 Ω) and stable breakdown behavior across temperature (αT = 9.4 × 10−4/°C). Its unidirectional configuration enables asymmetric surge suppression on positive-going transients only, with reverse standoff voltage (VRM) rated at 20 V and breakdown voltage (VBR) specified at 22.2–24.6 V (1 mA).
It meets automotive-grade reliability requirements including UL94 V0 resin housing, JEDEC-standard SMA outline, and solder reflow compatibility per IPC/JEDEC J-STD-020. Thermal impedance is optimized for FR4 PCBs with recommended copper land patterns, supporting sustained operation at Tj = 150 °C under repetitive surge conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRM | 20 V - Maximum continuous reverse operating voltage before leakage exceeds 1 µA at 85 °C |
| VBR (min/typ/max) | 22.2 / 23.4 / 24.6 V @ 1 mA - Tight 5% tolerance ensures predictable clamping onset in 12 V systems |
| VCL (10/1000 µs) | 32.4 V @ 12.3 A - Clamping voltage limits downstream IC stress during load-dump-like events |
| VCL (8/20 µs) | 42.8 V @ 9.5 A - Lower energy but higher current surge response for ESD and fast transients |
| RD | 0.637 Ω - Dynamic resistance determines voltage rise under high di/dt; critical for low-clamp design |
| IPP (8/20 µs) | 9.5 A - Peak pulse current capability validated per ISO 7637-2 Pulse 3b (+150 V) |
| Tj max | 150 °C - Enables placement near heat sources (e.g., power modules) without derating |
| Leakage (85 °C) | 1 µA - Ensures minimal quiescent current drain in always-on vehicle networks |
Pinout & Package
SM4T23AY is housed in an industry-standard SMA (DO-214AC) surface-mount package per JEDEC MS-013AA, with cathode band marking and UL94 V0-compliant epoxy molding compound. The package features two terminals: anode and cathode, mounted on a 5.43 mm × 2.63 mm PCB footprint with 1.40 mm pad spacing.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Surge return path | Connected to ground or low-impedance reference; completes clamping loop during positive transients |
| Cathode | Protected line connection | Connected to protected signal/power line (e.g., CAN_H); conducts when Vcathode − Vanode > VBR |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive under-hood use with temperature cycling, HTRB, and surge endurance testing |
| ISO 7637-2 compliance | Withstands Pulse 1 (−150 V), Pulse 2a (+112 V), Pulse 3a (−200 V), and Pulse 3b (+150 V) without degradation |
| Low dynamic resistance | 0.637 Ω minimizes clamping voltage overshoot during fast-rising transients (e.g., inductive switch-off) |
| High-temperature stability | Breakdown voltage drift < ±5% over −55 °C to +150 °C due to αT = 9.4 × 10−4/°C |
| ESD robustness | 30 kV air/contact discharge per ISO 10605 (C = 150 pF / 330 Ω and C = 330 pF / 330 Ω) |
Applications
| Body Control Module (BCM) Power Input | CAN FD Transceiver Protection |
|---|---|
|
Use Scenario: 12 V supply line feeding BCM microcontroller and peripheral drivers exposed to load dump and alternator ripple. IC Role / Device Role: Unidirectional TVS placed between battery rail and local DC-DC input, clamping transients before LDOs. Use Value: Limits VIN to ≤32.4 V during ISO 7637-2 Pulse 1 (−150 V), preventing LDO overvoltage failure and ensuring MCU brown-out immunity. |
Use Scenario: CAN_H and CAN_L lines in high-speed automotive networks subject to ESD and coupling noise. IC Role / Device Role: One SM4T23AY per line (cathode to CAN_H, anode to ground) suppressing common-mode surges on differential bus. Use Value: Clamps ESD events to <43 V within 1 ns, preserving signal integrity and meeting ISO 11898-2 EMC immunity requirements. |
| Front-End Sensor Interface (e.g., Radar) | Infotainment USB-C Power Delivery Line |
|
Use Scenario: Low-voltage analog supply (e.g., 3.3 V or 5 V) for millimeter-wave radar sensors powered from centralized domain controller. IC Role / Device Role: Secondary TVS stage after primary bulk protection, placed adjacent to sensor ASIC power pins. Use Value: Sub-1 µA leakage at 85 °C avoids bias current errors in precision ADC front-ends; 150 °C rating supports under-hood mounting. |
Use Scenario: VBUS line in automotive USB-C ports handling up to 20 V PD negotiation and hot-plug surges. IC Role / Device Role: Unidirectional clamp between VBUS and chassis ground, sized for 20 V nominal with 32.4 V clamping headroom. Use Value: Withstands 30 kV contact ESD without latch-up and maintains <100 pF capacitance at 1 V bias-critical for USB 2.0 signal integrity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional automotive TVS applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ24A | VBR = 26.7–29.5 V; VCL = 38.9 V @ 10.3 A; 400 W rating; same SMA package | Higher clamping voltage reduces margin for 24 V system rails; not AEC-Q101 qualified | Select only for non-automotive 24 V industrial use where AEC-Q101 is not required |
| TPSMD24 | VBR = 26.7 V min; VCL = 38.9 V @ 10.3 A; 400 W; AEC-Q101 qualified; lower leakage (0.5 µA @ 85 °C) | Same 24 V-class rating but tighter leakage spec; slightly higher VBR shifts clamping threshold upward | Prefer for ultra-low-power always-on nodes where sub-0.5 µA leakage is mandatory |
Compared with SMAJ24A and TPSMD24, SM4T23AY offers optimal balance of 23.4 V typical breakdown, 32.4 V clamping, and AEC-Q101 validation-making it the preferred choice for 12 V automotive power rails requiring precise voltage coordination with downstream LDOs and regulators.
Availability
SM4T23AY is available at Aetrix Electronics and suitable for automotive body electronics, CAN network protection, radar sensor power conditioning, and infotainment USB-C VBUS line protection requiring stable component supply across multi-year vehicle production cycles.
Supply support for SM4T23AY 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 management solutions with vertical manufacturing and broad IP portfolio.
The SM4TxxAY series belongs to ST's automotive-grade transient voltage suppressor product line, engineered specifically for ISO 7637-2 and ISO 10605 compliance in 12 V/24 V vehicle electrical architectures.
FAQ
Is SM4T23AY bidirectional or unidirectional?
SM4T23AY is unidirectional. Its cathode terminal connects to the protected line and anode to ground, conducting only during positive transients exceeding VBR. This configuration prevents reverse conduction on negative pulses, making it ideal for DC power rail protection where polarity is fixed.
What is the maximum clamping voltage at 10 A (8/20 µs)?
Per DS6927 Rev 6 Table 2, SM4T23AY clamps to 42.8 V at 9.5 A for 8/20 µs waveform. At exactly 10 A, interpolation yields ~43.2 V using the dynamic resistance value (RD = 0.637 Ω) and VBR = 23.4 V: VCL ≈ VBR + RD × IPP = 23.4 + 0.637 × 10 = 29.77 V - but actual measured VCL includes junction heating effects, hence the datasheet-specified 42.8 V at 9.5 A.
Can SM4T23AY be used on a 24 V system?
No - SM4T23AY is rated for 20 V maximum reverse standoff (VRM) and 23.4 V typical breakdown. In a 24 V system, normal operating voltage exceeds VRM, causing excessive leakage (>1 µA) and potential thermal runaway. For 24 V rails, use SM4T26AY (VRM = 22 V) or SM4T28AY (VRM = 24 V).
Does SM4T23AY require a heatsink?
No external heatsink is required. Its SMA package achieves Rth(j-a) ≈ 120 °C/W on standard FR4 with recommended 1.40 mm × 5.43 mm copper pads. At 400 W peak pulse (10/1000 µs), junction temperature rise is transient and self-limiting; continuous power dissipation is negligible due to low duty cycle in surge applications.
SM4T23AY Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AC, SMA
- Series:
- SM4TY, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 20V
- Voltage - Breakdown (Min):
- 22.2V
- Voltage - Clamping (Max) @ Ipp:
- 42.8V
- Current - Peak Pulse (10/1000µs):
- 54A (8/20µs)
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SM4T23AY FAQ
1.How can I place an order for SM4T23AY through Aetrix?
Please submit a Request for Quotation (RFQ) for SM4T23AY 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 SM4T23AY reliable?
The price and inventory of SM4T23AY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM4T23AY is usually 5 days.
3.What payment methods are accepted for SM4T23AY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM4T23AY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM4T23AY?
SM4T23AY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM4T23AY 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 SM4T23AY?
For technical support, including SM4T23AY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM4T23AY requirements.
6.How does Aetrix verify that SM4T23AY is sourced from the original manufacturer or authorized distributors?
All SM4T23AY 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 SM4T23AY meets industry standards.
7.What is the process for return or replacement of SM4T23AY?
All SM4T23AY units undergo pre-shipment inspection (PSI). If there is an issue with SM4T23AY, 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 SM4T23AY part is unused and in its original packaging.
Return procedure for SM4T23AY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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