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Home > Products > Circuit Protection > Transient Voltage Suppressors (TVS) > TVS Diodes

STMicroelectronics SM4T10AY

Name: SM4T10AY
Brand: STMicroelectronics
SKU: SM4T10AY
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SM4T10AY

Manufacturer:: STMicroelectronics

Category:: TVS Diodes

Package:: DO-214AC, SMA

Datasheet:: SM4T10AY.pdf

Description:: TVS DIODE 8.5VWM 19.5VC SMA

Quantity:: RFQ Add To RFQ list

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Inventory:4,970

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Product details

Overview

SM4T10AY from STMicroelectronics is an AEC-Q101-qualified unidirectional automotive TVS diode in SMA package, designed to clamp transient overvoltages up to 14.4 V (V_CL) at 27.7 A (I_PP) under 10/1000 µs surge, with 400 W peak pulse power and 8.5–10.4 V breakdown voltage range. It protects CAN, LIN, and sensor supply lines in 12 V automotive systems against ISO 7637-2 pulses and ISO 10605 ESD events.

For engineers reviewing the SM4T10AY datasheet, SM4T10AY pinout, SM4T10AY application, or SM4T10AY equivalent, this device is selected for robust front-end protection in battery-supplied ECUs where low leakage (<1 µA at 85 °C), high T_j capability (150 °C), and JEDEC-compliant SMA footprint are required.

Technical Context

The SM4T10AY uses planar junction technology to achieve stable V_BR temperature coefficient (α_T = 7.3 × 10⁻⁴/°C) and low dynamic resistance (R_D = 0.145 Ω), enabling precise clamping during fast transients. Its unidirectional configuration supports cathode-to-rail placement for reverse-polarity and load-dump suppression.

It meets ISO 7637-2 Pulse 1 (−150 V), Pulse 2a (+112 V), Pulse 3a (−200 V), and Pulse 3b (+150 V) without derating at T_j ≤ 150 °C, and delivers 30 kV ESD immunity per ISO 10605 (150 pF/330 Ω and 330 pF/330 Ω).

Key Specifications

Parameter	Value and Actual Design Meaning
V_BR (min–max)	8.5–10.4 V at I_BR = 1 mA: defines reliable turn-on threshold across temperature and unit variation
V_CL @ 10/1000 µs	14.4 V at I_PP = 27.7 A: maximum clamped voltage seen by protected IC during slow surges
Peak Pulse Power	400 W (10/1000 µs): sustains automotive load-dump energy without failure
I_R @ V_RM	1 µA max at 85 °C: ensures minimal standby current drain in always-on modules
T_j max	150 °C: enables operation adjacent to hot engine-control components
Package	SMA (JEDEC DO-214AC): surface-mount footprint compatible with IPC-7531 standard PCB layout
ESD Rating	±30 kV contact/air (ISO 10605): exceeds automotive infotainment and body control ESD requirements

Pinout & Package

SMA package (DO-214AC) with cathode band marking; two-terminal device requiring no biasing-cathode connects to protected line, anode to ground or lower potential rail.

Pin/Terminal	Circuit Role	Design Meaning
Anode	Reference node	Connected to GND or low-side return path; establishes clamping reference for unidirectional operation
Cathode	Protected line interface	Connected to signal/power line (e.g., CAN_H, LIN bus, sensor V_CC); conducts surge current to ground when V_AK > V_BR

Key Features

Feature	Design Value
AEC-Q101 qualification	Validated for automotive under-hood and chassis applications per stress test requirements
Low dynamic resistance (R_D)	0.145 Ω enables tighter clamping margin and reduced overshoot during fast transients
High junction temperature rating	150 °C continuous operation supports placement near power stages and motor drivers
UL94 V0 resin housing	Flame-retardant encapsulation meets automotive cabin and engine bay safety standards
Planar junction construction	Delivers stable leakage and V_BR drift over lifetime, critical for long-term reliability in 15+ year vehicles

Applications

Engine Control Unit (ECU) Power Input

CAN Bus Physical Layer Protection

Use Scenario: Protects 12 V supply rail of engine management ECU against load dump (ISO 7637-2 Pulse 2a) and alternator ripple-induced surges.

IC Role / Device Role / Timing Role: Unidirectional TVS placed between battery input and DC-DC converter input, clamping transients before they reach downstream regulators.

Use Value: Limits peak voltage to 14.4 V, preventing overvoltage damage to 16 V-rated input capacitors and LDOs.

Use Scenario: Shields CAN transceiver pins (CAN_H/CAN_L) from ESD events during vehicle assembly and service operations.

IC Role / Device Role / Timing Role: Two SM4T10AY devices (one per line) placed at connector entry point, referenced to chassis ground.

Use Value: Clamps ±30 kV ESD strikes to <15 V within nanoseconds, preserving transceiver integrity without signal distortion.

LIN Bus Sensor Interface

Body Control Module (BCM) Power Rail

Use Scenario: Guards LIN slave nodes (e.g., door lock actuators, mirror controls) against battery reversal and jump-start transients.

IC Role / Device Role / Timing Role: Unidirectional TVS on LIN bus line, anode grounded, cathode tied to LIN signal trace.

Use Value: Withstands −150 V ISO 7637-2 Pulse 1 while maintaining <1 µA leakage at 85 °C for ultra-low-power sleep modes.

Use Scenario: Safeguards 5 V/3.3 V power rails in BCMs exposed to ignition noise and relay switching spikes.

IC Role / Device Role / Timing Role: Secondary TVS stage after primary fuse and LC filter, placed close to microcontroller power pins.

Use Value: Provides 400 W surge handling with 0.145 Ω R_D, minimizing voltage rise during 100 ns–1 ms transients.

Equivalent & Alternatives

The following parts are listed as comparable options for similar unidirectional automotive TVS protection applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
SMAJ10A	Lower peak power (400 W same), but higher V_CL (16.7 V @ 25.2 A) and wider V_BR tolerance (9.4–11.6 V)	Less margin for 12 V systems with tight downstream voltage limits	Prefer SM4T10AY where clamping voltage headroom is constrained
1.5SMC10A	Higher package thermal resistance (SMA vs. SMC), lower I_PP rating (25.2 A vs. 27.7 A at same waveform), and no AEC-Q101 certification	Not qualified for automotive production; limited to industrial or consumer use	Select SM4T10AY for OEM automotive programs requiring full qualification traceability

Compared with SMAJ10A and 1.5SMC10A, SM4T10AY offers tighter V_CL (14.4 V), lower R_D (0.145 Ω), and full AEC-Q101 compliance-making it optimal for space-constrained, high-reliability 12 V automotive nodes where clamping precision and qualification are mandatory.

Availability

SM4T10AY is available at Aetrix Electronics and suitable for engine control units, CAN/LIN bus interfaces, body electronics modules, and ADAS sensor power supplies requiring stable component supply across automotive production lifecycles.

Supply support for SM4T10AY 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 vertical manufacturing and AEC-Q101 validation infrastructure.

The SM4TxxAY series belongs to ST's automotive-grade TVS portfolio, engineered specifically for ISO 7637-2 and ISO 10605 compliance in 12 V vehicle electrical architectures.

FAQ

What is the maximum clamping voltage of SM4T10AY under a 10/1000 µs surge?

The maximum clamping voltage (V_CL) is 14.4 V at 27.7 A peak pulse current for the 10/1000 µs waveform, measured at T_amb = 25 °C. This value increases linearly with junction temperature using α_T = 7.3 × 10⁻⁴/°C, reaching ~15.1 V at T_j = 125 °C.

Is SM4T10AY bidirectional or unidirectional?

SM4T10AY is unidirectional: it conducts only when cathode voltage exceeds anode voltage by ≥V_BR. The "A" suffix denotes unidirectional configuration; "CAY" variants (e.g., SM4T10CAY) are bidirectional. Polarity must match circuit grounding topology.

Does SM4T10AY require a heatsink for 400 W surge dissipation?

No external heatsink is required. The 400 W rating applies to single-pulse conditions with proper PCB copper area (≥1.64 cm² per lead, per Figure 12). Thermal resistance drops to ~3.5 °C/W with recommended FR4 layout, limiting ΔT to <140 °C during transient.

Can SM4T10AY be used in 24 V commercial vehicle systems?

Not recommended as primary protection: its V_BR (8.5–10.4 V) and V_CL (14.4 V) are optimized for 12 V nominal systems. For 24 V applications, ST recommends SM4T24AY (V_BR = 21.1–23.4 V) or SM4T26AY to maintain adequate margin above operating voltage.

SM4T10AY 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):: 8.5V

Voltage - Breakdown (Min):: 9.4V

Voltage - Clamping (Max) @ Ipp:: 19.5V

Current - Peak Pulse (10/1000µs):: 124A (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)

SM4T10AY FAQ

1.How can I place an order for SM4T10AY through Aetrix?

Please submit a Request for Quotation (RFQ) for SM4T10AY 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 SM4T10AY reliable?

The price and inventory of SM4T10AY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM4T10AY is usually 5 days.

3.What payment methods are accepted for SM4T10AY?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM4T10AY transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SM4T10AY?

SM4T10AY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SM4T10AY 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 SM4T10AY?

For technical support, including SM4T10AY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM4T10AY requirements.

6.How does Aetrix verify that SM4T10AY is sourced from the original manufacturer or authorized distributors?

All SM4T10AY 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 SM4T10AY meets industry standards.

7.What is the process for return or replacement of SM4T10AY?

All SM4T10AY units undergo pre-shipment inspection (PSI). If there is an issue with SM4T10AY, 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 SM4T10AY part is unused and in its original packaging.

Return procedure for SM4T10AY:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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