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STMicroelectronics SM4T14CAY
- Part No.:
- SM4T14CAY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SM4T14CAY.pdf
- Description:
- TVS DIODE 12VWM 25.3VC SMA
- Quantity:
- Payment:
- Shipping:
Inventory:2,500
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Product details
Overview
SM4T14CAY from STMicroelectronics is a bidirectional automotive-grade transient voltage suppression (TVS) diode designed for ISO 7637-2 and ISO 10605 surge/ESD protection in 12 V vehicle power networks. It features a 14 V nominal breakdown voltage (VBR = 13.3–14.7 V), 19.9 V clamping voltage at 20.1 A (8/20 µs), 400 W peak pulse power (10/1000 µs), and operates up to 150 °C junction temperature.
For engineers reviewing the SM4T14CAY datasheet, SM4T14CAY pinout, SM4T14CAY application, or SM4T14CAY equivalent, key selection criteria include unidirectional/bidirectional polarity confirmation, clamping performance under ISO 7637-2 Pulse 1/2a/3a/3b, leakage current at elevated temperature (≤1 µA @ 85 °C), and SMA package thermal resistance on FR4 PCB.
Technical Context
The SM4T14CAY implements planar silicon junction technology optimized for low leakage (<0.2 µA @ 25 °C) and high-temperature stability (Tj max = 150 °C), enabling long-term reliability in engine bay and ADAS modules. Its bidirectional configuration provides symmetrical clamping for both positive and negative transients without external polarity management.
It meets AEC-Q101 qualification and complies with ISO 10605 (±30 kV ESD) and ISO 7637-2 (Pulse 1: −150 V; Pulse 2a: +112 V; Pulse 3a: −200 V; Pulse 3b: +150 V), making it suitable for unprotected CAN/LIN bus lines, sensor supply rails, and infotainment power inputs in 12 V systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VBR (min/typ/max) | 13.3 / 14.0 / 14.7 V - Ensures reliable turn-on before downstream IC damage during load dump or inductive switching |
| VCL @ IPP = 20.1 A (8/20 µs) | 19.9 V - Limits voltage seen by protected circuit during fast, high-energy transients like ESD or ignition noise |
| IR @ VRM = 12 V | 0.2 µA @ 25 °C, 1 µA @ 85 °C - Minimizes standby power loss and avoids false triggering in low-current sensor circuits |
| PPP (10/1000 µs) | 400 W - Sustains standard automotive load-dump surges without degradation |
| Tj operating range | −55 to +150 °C - Supports placement near heat sources (e.g., ECUs, power converters) without derating |
| Package | SMA (DO-214AC) - JEDEC-registered surface-mount outline with 5.35 mm × 4.60 mm footprint and 1.5 mm height |
Pinout & Package
SMA (DO-214AC) package: single-body, two-terminal surface-mount device with cathode band marking; terminals are non-polarized for bidirectional operation and require no orientation-dependent routing.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode/Cathode (bidirectional) | Surge current path | Both terminals conduct equally during ± transients; no DC polarity dependency-ideal for AC-coupled signal lines or floating power rails |
| Cathode band (marking) | Manufacturing reference | Indicates terminal location only; irrelevant for electrical function in bidirectional configuration |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive underhood use with extended temperature cycling, humidity, and mechanical shock testing |
| Low dynamic resistance (RD = 0.116 Ω) | Minimizes clamping voltage rise under high di/dt events such as ISO 7637-2 Pulse 3b (+150 V) |
| UL94 V0-compliant resin | Meets flammability requirements for enclosed automotive electronics housings |
| Planar junction construction | Enables stable leakage and VBR drift over lifetime at Tj = 150 °C |
Applications
| Engine Control Unit (ECU) Power Input | CAN Bus Transceiver Protection |
|---|---|
Use Scenario: Protects 12 V supply rail of engine control units against load dump (ISO 7637-2 Pulse 1) and alternator ripple. IC Role / Device Role / Timing Role: Bidirectional TVS clamps both positive and negative transients without requiring series blocking diodes. Use Value: Prevents brownout or latch-up in microcontrollers and analog front-ends during cranking and battery disconnection events. | Use Scenario: Shields high-speed CAN FD transceivers from ESD (ISO 10605 ±30 kV) and coupled noise on vehicle harnesses. IC Role / Device Role / Timing Role: Low-capacitance (≈100 pF @ 1 V) bidirectional clamp maintains signal integrity up to 5 Mbps. Use Value: Eliminates need for separate positive/negative TVS devices while preserving common-mode rejection and bus timing margins. |
| ADAS Camera Module Power Rail | Body Control Module (BCM) LIN Bus |
Use Scenario: Secures 5 V or 3.3 V DC-DC output feeding image sensors and ISP processors in front/rear cameras. IC Role / Device Role / Timing Role: Clamps fast-rising transients (e.g., relay bounce, motor commutation) before they couple into low-noise analog imaging paths. Use Value: Reduces pixel noise, hot pixels, and frame dropouts caused by sub-100 ns voltage spikes on power domains. | Use Scenario: Guards LIN transceiver supply and data lines against battery reversal, jump-start surges, and electrostatic discharge in door modules and seat controls. IC Role / Device Role / Timing Role: Unidirectional variant not required-bidirectional symmetry simplifies layout and eliminates polarity error risk during assembly. Use Value: Enables single-device protection across both LIN master and slave nodes without redesigning PCB silkscreen or BOM variants. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ14CA | Lower PPP (400 W same), but higher VCL = 23.2 V @ 17.3 A (8/20 µs); RD = 0.23 Ω | Less effective clamping margin for 12 V systems with tight 20 V downstream IC limits | Prefer SM4T14CAY where VCL ≤ 20 V is mandatory for 24 V tolerant receivers |
| 1.5KE14CA | Through-hole DO-201 package; higher VCL = 22.5 V @ 17.8 A; Tj max = 175 °C but no AEC-Q101 qualification | Not suitable for automated SMT production or automotive qualification programs | Select SM4T14CAY for volume automotive PCB assembly and OEM compliance requirements |
Compared with SMAJ14CA and 1.5KE14CA, SM4T14CAY delivers tighter clamping (19.9 V vs. ≥22.5 V), lower dynamic resistance (0.116 Ω), and full AEC-Q101 validation-making it the preferred choice for space-constrained, high-reliability 12 V automotive power rail protection.
Availability
SM4T14CAY is available at Aetrix Electronics and suitable for engine control units, ADAS camera modules, body control modules, and CAN/LIN network nodes requiring stable component supply across automotive production lifecycles.
Supply support for SM4T14CAY 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 SM4Txx series belongs to ST's automotive-grade TVS portfolio, engineered specifically for robust transient immunity in 12 V vehicle electrical architectures per ISO 7637-2 and ISO 10605.
FAQ
Is SM4T14CAY unidirectional or bidirectional?
SM4T14CAY is a bidirectional TVS diode, indicated by the "C" in its part number. It provides symmetrical clamping for both positive and negative voltage transients without polarity sensitivity-ideal for protecting AC-coupled signals or floating power rails in automotive systems.
What is the maximum clamping voltage under ISO 7637-2 Pulse 3b?
Under ISO 7637-2 Pulse 3b (+150 V, 50 Ω source), SM4T14CAY clamps to ≤19.9 V at 20.1 A (8/20 µs waveform). Its low dynamic resistance (0.116 Ω) ensures minimal voltage overshoot during this fast-rising transient, protecting downstream 20 V-rated ICs.
Does SM4T14CAY require heatsinking on standard FR4 PCB?
No additional heatsink is required. With Rth(j-a) ≈ 120 °C/W on a 1 cm² copper pad per lead (per Figure 12), and Tj max = 150 °C, the device safely handles 400 W pulses for <1 ms without exceeding junction limits-provided recommended SMA footprint (Figure 18) is used.
How does SM4T14CAY differ from SM4T14AY?
SM4T14AY is unidirectional (anode-cathode polarized), while SM4T14CAY is bidirectional (symmetrical conduction). The "C" suffix denotes bidirectional capability-critical for protecting differential buses (e.g., CAN) or circuits exposed to reverse battery conditions without adding external diodes.
SM4T14CAY 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:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 12V
- Voltage - Breakdown (Min):
- 13.3V
- Voltage - Clamping (Max) @ Ipp:
- 25.3V
- Current - Peak Pulse (10/1000µs):
- 91A (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)
SM4T14CAY FAQ
1.How can I place an order for SM4T14CAY through Aetrix?
Please submit a Request for Quotation (RFQ) for SM4T14CAY 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 SM4T14CAY reliable?
The price and inventory of SM4T14CAY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM4T14CAY is usually 5 days.
3.What payment methods are accepted for SM4T14CAY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM4T14CAY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM4T14CAY?
SM4T14CAY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM4T14CAY 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 SM4T14CAY?
For technical support, including SM4T14CAY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM4T14CAY requirements.
6.How does Aetrix verify that SM4T14CAY is sourced from the original manufacturer or authorized distributors?
All SM4T14CAY 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 SM4T14CAY meets industry standards.
7.What is the process for return or replacement of SM4T14CAY?
All SM4T14CAY units undergo pre-shipment inspection (PSI). If there is an issue with SM4T14CAY, 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 SM4T14CAY part is unused and in its original packaging.
Return procedure for SM4T14CAY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SM4T14CAY Tags
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