STMicroelectronics SM15T75A

Overview

SM15T75A from STMicroelectronics is a unidirectional 1500 W transient voltage suppression diode in SMC package, designed for IEC 61000-4-2 ESD (30 kV air/contact) and IEC 61000-4-4 surge (4 kV level 4) protection. It features 75 V breakdown voltage (V_BR = 64.1–78.8 V), 103 V clamping voltage at 14.6 A (8/20 µs), and 0.2 µA max leakage at 25 °C. Used in AC/DC power inputs and telecom line interfaces where high junction temperature (T_j up to 150 °C) and low leakage ensure long-term reliability.

For engineers reviewing the SM15T75A datasheet, SM15T75A pinout, SM15T75A application, or SM15T75A equivalent, this page delivers verified electrical parameters, SMC package mechanical data, real-world clamping behavior under 8/20 µs and 10/1000 µs surges, thermal derating curves, and direct alternatives with documented V_BR, V_CL, and R_D differences.

Technical Context

The SM15T75A employs planar silicon avalanche technology optimized for fast response (<1 ns) to electrostatic discharge and repetitive surge events. Its unidirectional configuration provides asymmetric conduction-low forward voltage drop (V_F ≤ 3 V at 100 A) and high reverse standoff (V_RWM = 64.1 V min) with precise V_BR tolerance (±5% typical).

Thermal performance is defined by junction-to-ambient thermal resistance (R_th(j-a) ≈ 100 °C/W on standard FR4 footprint) and dynamic resistance (R_D = 1.66 Ω at 25 °C), enabling stable clamping across operating temperatures (−55 to +150 °C) without parameter drift beyond α_T = 10.5 × 10⁻⁴/°C coefficient.

Key Specifications

Pinout & Package

SM15T75A uses the industry-standard SMC (DO-214AB) surface-mount package: 7.75–8.15 mm length, 5.55–6.25 mm width, 2.45 mm max height, matte tin-plated leads compliant with J-STD-002 and JEDEC MO-136. Thermal pad area under each lead directly impacts R_th(j-a); recommended copper area is ≥3 cm² per lead.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar transient voltage suppression applications.

Compared with SMAJ75A and SMA6J75A, SM15T75A delivers lower clamping voltage (103 V vs. ≥107 V) and superior leakage performance (0.2 µA vs. ≥1 µA), making it optimal for high-reliability 24 V industrial I/O and low-power automotive subsystems where voltage margin and quiescent current are critical.

Availability

SM15T75A is available at Aetrix Electronics and suitable for AC/DC power input protection, telecom line interface hardening, industrial PLC digital I/O safeguarding, and automotive body control module surge suppression requiring stable component supply across extended temperature ranges and high-volume production cycles.

Supply support for SM15T75A 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, delivering silicon solutions for automotive, industrial, and power management applications with emphasis on reliability and environmental compliance.

The SM15T series belongs to ST's high-power TVS diode product line, engineered specifically for robust IEC 61000-4-2/4-4/4-5 transient protection in harsh environments where thermal stability and low leakage are non-negotiable.

FAQ

What is the maximum clamping voltage of SM15T75A under an 8/20 µs surge?

The maximum clamping voltage (V_CL) of SM15T75A is 103 V when subjected to a 14.6 A peak pulse current with 8/20 µs waveform, measured at T_j = 25 °C. This value increases linearly with junction temperature at α_T = 10.5 × 10⁻⁴/°C, reaching ~112 V at T_j = 125 °C.

Can SM15T75A be used in bidirectional signal lines?

No - SM15T75A is a unidirectional TVS diode intended for DC-biased circuits like power rails or single-ended data lines referenced to ground. For bidirectional protection (e.g., RS-485, USB D+/D−), the SM15T75CA variant must be used, which features symmetrical breakdown in both polarities.

How does SM15T75A's dynamic resistance affect its clamping performance?

With a dynamic resistance (R_D) of 1.66 Ω at 25 °C, SM15T75A exhibits predictable V_CL rise proportional to surge current deviation: V_CL(max) = V_CL − R_D × (I_PP − I_appli). This allows accurate system-level overvoltage margin calculation for custom surge profiles.

Is SM15T75A compatible with lead-free reflow soldering processes?

Yes - SM15T75A is qualified for lead-free reflow per J-STD-020 MSL level 1, with peak temperature tolerance up to 260 °C for 10 seconds. Its recommended reflow profile specifies 240–245 °C peak, 60-second liquidus duration, and ramp rates ≤3 °C/s, matching standard Pb-free PCB assembly lines.