STMicroelectronics SM15T75CAY

Overview

SM15T75CAY from STMicroelectronics is a bidirectional automotive-grade transient voltage suppression (TVS) diode in SMC package, designed for ISO 7637-2 pulse protection and ISO 10605 ESD immunity in 12 V/24 V vehicle systems. It features 75 V breakdown voltage (V_BR = 75 V), 103 V clamping voltage (V_CL) at 14.6 A (10/1000 µs), 1500 W peak pulse power, and AEC-Q101 qualification for under-hood applications.

For engineers reviewing the SM15T75CAY datasheet, SM15T75CAY pinout, SM15T75CAY application, or SM15T75CAY equivalent, this device is selected for high-reliability surge protection in automotive power line interfaces where low leakage (<1 µA at 85 °C), high junction temperature operation (T_j up to 150 °C), and bidirectional clamping symmetry are required.

Technical Context

This bidirectional TVS diode uses planar silicon technology to achieve stable V_BR tolerance (±5% at 75 V), low dynamic resistance (R_D = 0.74 Ω), and symmetric clamping behavior in both polarities. Its thermal design supports 1250 W derated pulse power at T_j = 150 °C per Figure 3 of DS6928.

It meets stringent automotive immunity standards: ISO 10605 (30 kV air/contact discharge), IEC 61000-4-2 (30 kV), IEC 61000-4-4 Level 4 (4 kV), and ISO 7637-2 pulses (Pulse 1: −150 V; Pulse 2a: +112 V; Pulse 3a: −220 V; Pulse 3b: +150 V), with no minimum stand-off voltage restriction for battery-line use.

Key Specifications

Pinout & Package

SM15T75CAY is a two-terminal bidirectional TVS diode in SMC (DO-214AB) package. The device has no polarity marking; both terminals are electrically symmetric and interchangeable in circuit layout.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ75CA and SMA6J75CA, SM15T75CAY delivers lower clamping (103 V vs. 121 V), lower dynamic resistance (0.74 Ω vs. 0.98 Ω), and full ISO 7637-2 validation - enabling tighter voltage margins and verified robustness in automotive power line designs.

Availability

SM15T75CAY is available at Aetrix Electronics and suitable for automotive ECU power protection, body electronics CAN interface hardening, ADAS camera supply conditioning, and electric power steering motor driver safeguarding requiring stable component supply across multi-year production cycles.

Supply support for SM15T75CAY 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 over 45 years of analog and protection device innovation.

The SM15Txx series belongs to ST's automotive-grade TVS portfolio, engineered specifically for ISO 7637-2 and ISO 10605 compliance in harsh-temperature vehicle environments - targeting battery line, infotainment, and ADAS subsystem protection.

FAQ

What is the maximum clamping voltage of SM15T75CAY under a 10/1000 µs surge?

The maximum clamping voltage is 103 V at 14.6 A for a 10/1000 µs waveform, measured at T_amb = 25 °C. This value increases with junction temperature at a coefficient of 10.5 × 10⁻⁴/°C, reaching approximately 112 V at T_j = 150 °C per the α_T parameter in Table 2.

Is SM15T75CAY suitable for protecting CAN FD physical layer interfaces?

Yes - its bidirectional symmetry, 30 kV ESD immunity (ISO 10605), and low leakage (<1 µA at 85 °C) make it appropriate for CAN FD bus protection. Two devices can be placed across CAN_H–GND and CAN_L–GND to suppress common-mode transients without affecting signal edge rates or bus termination.

Does SM15T75CAY require heatsinking in typical automotive applications?

No - the SMC package and planar die architecture enable full 1500 W surge handling at T_j = 25 °C and 1250 W at T_j = 150 °C without external heatsinking, provided the PCB uses the recommended IPC7531 footprint with ≥3.14 cm² copper area per lead per Figure 12.

How does SM15T75CAY differ from unidirectional SM15T75AY in circuit implementation?

SM15T75CAY provides identical clamping in both directions and connects across power rail and ground without polarity concern; SM15T75AY is unidirectional and must be oriented with cathode toward the protected rail. CAY type is mandatory for AC-coupled or floating-bus applications like CAN, LIN, or differential signaling.