STMicroelectronics SM15T30AY

Overview

SM15T30AY from STMicroelectronics is a unidirectional automotive-grade transient voltage suppression diode in SMC package, designed for ISO 7637-2 pulse protection in 12 V vehicle systems. It features a 30 V nominal breakdown voltage (V_BR = 25.6–31.5 V), 41.5 V clamping voltage (V_CL) at 36 A (10/1000 µs), 1500 W peak pulse power, and AEC-Q101 qualification for under-hood reliability.

For engineers reviewing the SM15T30AY datasheet, SM15T30AY pinout, SM15T30AY application, or SM15T30AY equivalent, this TVS diode is selected for robust ESD and surge protection in automotive power line interfaces-particularly where low leakage (0.2 µA @ 25 °C), high junction temperature operation (T_j up to +150 °C), and stable clamping under ISO 7637-2 Pulse 1/2a/3a/3b are required.

Technical Context

The SM15T30AY implements planar junction technology to achieve low leakage current and stable V_BR drift over temperature (α_T = 9.7 × 10⁻⁴/°C). Its unidirectional configuration provides forward conduction path only during reverse surge events, enabling precise clamping on battery-supplied lines without interfering with normal DC bias.

It meets IEC 61000-4-2 Level 4 (±30 kV air/contact discharge) and ISO 10605 (C = 150/330 pF, R = 330 Ω), with dynamic resistance (R_D) of 0.278 Ω at 10/1000 µs, ensuring fast response and minimal overshoot during transient events up to 10 kW (8/20 µs).

Key Specifications

Pinout & Package

SM15T30AY is a two-terminal unidirectional TVS diode in SMC (DO-214AB) package. Cathode is marked with a band; anode is unmarked. The device has no internal logic or control pins-only functional terminals for series connection across protected lines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ30A and 1.5KE30A, SM15T30AY delivers superior automotive reliability via AEC-Q101 qualification, tighter V_CL (41.5 V vs. ≥43.5 V), lower leakage (0.2 µA vs. ≥1 µA), and SMC packaging optimized for high-volume SMT assembly and thermal performance in constrained spaces.

Availability

SM15T30AY is available at Aetrix Electronics and suitable for engine control units, body control modules, infotainment power ports, and ADAS camera supplies requiring stable component supply across automotive production lifecycles.

Supply support for SM15T30AY 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 SM15TxxAY series belongs to ST's automotive-grade TVS portfolio, engineered specifically for ISO 7637-2 and ISO 10605 compliance in 12 V and 24 V vehicle architectures-prioritizing low leakage, high T_j stability, and planar junction reliability.

FAQ

What is the maximum clamping voltage of SM15T30AY under a 10/1000 µs surge?

The maximum clamping voltage (V_CL) is 41.5 V at 36 A for a 10/1000 µs waveform, measured at T_amb = 25 °C. This value increases linearly with junction temperature using α_T = 9.7 × 10⁻⁴/°C, reaching ~44.2 V at T_j = +150 °C.

Is SM15T30AY suitable for bidirectional signal line protection?

No-SM15T30AY is unidirectional and intended for DC power line protection only. For bidirectional signal lines like CAN or LIN, ST offers the SM15T30CAY variant, which provides symmetrical clamping in both polarities and matches the same V_BR, V_CL, and surge ratings.

How does the SMC package of SM15T30AY improve thermal performance over SMA?

The SMC package (DO-214AB) offers 30% larger copper pad area and 25% lower thermal resistance (R_th(j-a)) than SMA (DO-214AC), enabling 1250 W surge handling at +150 °C junction temperature-critical for under-hood placement where ambient exceeds +105 °C.

Does SM15T30AY require derating for operation at 85 °C ambient temperature?

Yes-while rated for T_j up to +150 °C, ambient temperature rise must be managed via PCB copper area and airflow. At T_amb = +85 °C, maximum allowable power dissipation drops to ~950 W (10/1000 µs) per Figure 3 in DS6928, requiring thermal design verification using the recommended footprint and FR4 board stack-up.