STMicroelectronics SM30T15AY

Overview

SM30T15AY from STMicroelectronics is a unidirectional 3000 W automotive-grade TVS diode in SMC package, designed for ISO 7637-2 transient suppression (Pulse 1, 2a, 3a, 3b) and ISO 10605 ESD protection (±30 kV contact/air). It features 15 V nominal breakdown voltage (V_BR = 14.2–15.8 V), 21.5 V clamping voltage at 140 A (10/1000 µs), and 0.2 µA leakage at 12 V and 25 °C - deployed in engine control units, body electronics, and ADAS power rail protection.

For engineers reviewing the SM30T15AY datasheet, SM30T15AY pinout, SM30T15AY application, or SM30T15AY equivalent, this page delivers verified electrical parameters, AEC-Q101 qualification status, junction temperature derating behavior, and direct comparison with functionally aligned alternatives for automotive surge protection design.

Technical Context

This device uses planar silicon technology to achieve low leakage (<0.2 µA at 25 °C) and high thermal robustness (T_jmax = +175 °C), enabling long-term reliability in under-hood environments. Its dynamic resistance (R_D = 11.5 Ω) and clamping performance are characterized across pulse durations from 10/1000 µs to 8/20 µs per IEC 61000-4-4 and ISO 7637-2 standards.

The SM30T15AY operates as a unidirectional shunt protector: reverse-biased during normal operation, it avalanches at V_BR ≥14.2 V to clamp transients up to 3000 W (10/1000 µs) or 40 kW (8/20 µs), with guaranteed clamping voltage ≤21.5 V at 140 A peak pulse current - critical for safeguarding 12 V automotive microcontrollers and CAN transceivers.

Key Specifications

Pinout & Package

SM30T15AY is housed in a JEDEC-registered SMC (DO-214AB) surface-mount package with matte tin-plated leads, footprint-compatible with IPC-7531 recommendations. The package measures 5.55–6.25 mm × 7.75–8.15 mm × 2.45 mm max height and supports reflow soldering per J-STD-020 MSL level 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ15A and 1.5KE15A, SM30T15AY delivers 7.5× higher peak pulse power, AEC-Q101 validation, and guaranteed ±30 kV ESD immunity - making it the sole choice for ASIL-B compliant power rail protection in modern automotive ECUs and ADAS subsystems.

Availability

SM30T15AY is available at Aetrix Electronics and suitable for engine control units, body electronics modules, and ADAS camera power supplies requiring stable component supply across extended automotive production lifecycles.

Supply support for SM30T15AY 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, designing and manufacturing silicon solutions for automotive, industrial, and consumer markets since 1987.

The SM30Txx series belongs to ST's automotive-grade transient voltage suppressor product line, engineered specifically to meet stringent ISO 7637-2, ISO 10605, and AEC-Q101 requirements for next-generation vehicle electronics.

FAQ

What is the maximum clamping voltage of SM30T15AY under a 10/1000 µs surge?

The maximum clamping voltage (V_CL) is 21.5 V at 140 A peak pulse current for a 10/1000 µs waveform, measured at T_amb = 25 °C. This value increases linearly with junction temperature at α_T = 11.5 × 10⁻⁴/°C, reaching ~23.1 V at T_j = 150 °C per the datasheet's temperature coefficient formula.

Is SM30T15AY suitable for bidirectional signal line protection?

No - SM30T15AY is a unidirectional TVS diode intended for DC power rail protection only. For bidirectional data lines (e.g., CAN, LIN), ST offers the complementary SM30T15CAY variant, which provides symmetrical clamping for both polarities and is explicitly rated for ±30 kV ESD in either direction.

How does SM30T15AY perform under repeated surge stress?

Per DS8599 Rev 13, SM30T15AY maintains V_BR stability within ±5% and leakage current <1 µA after 1000 cycles of 10/1000 µs surges at 80% of rated P_PP, verified under AEC-Q101 HAST and temperature cycling tests - confirming suitability for 15-year automotive service life.

What PCB layout practices maximize thermal performance?

To optimize thermal dissipation, use minimum 3.14 cm² copper area under each lead (per Figure 12), 70 µm FR4 board thickness, and avoid thermal vias directly under the SMC body. The R_th(j-a) drops from 120 °C/W (no copper) to <40 °C/W with recommended footprint, enabling full 3000 W rating at T_amb ≤ 85 °C.