STMicroelectronics SMM4F5.0A-TR

Overview

SMM4F5.0A-TR from STMicroelectronics is a unidirectional 400 W transient voltage suppression diode designed for primary-level ESD and surge protection in low-voltage DC power rails and signal lines. It features a stand-off voltage of 5.0 V, clamping voltage of 9.2 V at 43.5 A (10/1000 µs), leakage current ≤0.2 µA at 25 °C, and operates up to 175 °C junction temperature - ideal for automotive infotainment power inputs and USB Type-C VBUS protection.

For engineers reviewing the SMM4F5.0A-TR datasheet, SMM4F5.0A-TR pinout, SMM4F5.0A-TR application, or SMM4F5.0A-TR equivalent, key selection criteria include clamping performance at 43.5 A, thermal robustness to 175 °C, flat STmite Flat package compatibility with high-density PCB layouts, and IEC 61000-4-2 level 4 compliance (±30 kV contact/air discharge).

Technical Context

This TVS diode uses planar silicon technology to achieve low leakage (<0.2 µA @ 25 °C) and stable breakdown behavior across –55 °C to +175 °C operating range. Its unidirectional configuration enables asymmetric surge handling on positive-only rails, with dynamic resistance of 0.047 Ω enabling tight clamping during 10/1000 µs transients.

The STmite Flat package (1.90 mm × 3.80 mm × 0.85 mm) supports high thermal dissipation via optimized copper pad layout, delivering 160 W peak pulse power at Tj = 175 °C - critical for sustained surge events in automotive and industrial environments where ambient temperatures exceed 105 °C.

Key Specifications

Pinout & Package

STmite Flat surface-mount package: 1.90 mm × 3.80 mm footprint, 0.85 mm height, matte tin-plated leads, JEDEC-compliant outline, IPC7531 footprint compatible. Cathode marked by bar on top surface.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ5.0A and SMF5.0A, the SMM4F5.0A-TR delivers superior thermal endurance (175 °C vs. 150 °C), tighter clamping (9.2 V vs. ≥9.8 V), and smaller volume (1.9 × 3.8 × 0.85 mm), making it optimal for next-gen automotive and compact industrial modules requiring high-reliability surge immunity.

Availability

SMM4F5.0A-TR is available at Aetrix Electronics and suitable for automotive infotainment power inputs, USB Type-C VBUS protection, and industrial PLC digital I/O protection requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for SMM4F5.0A-TR 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 microcontrollers, power devices, sensors, and analog ICs for automotive, industrial, and consumer markets.

The SMM4F series belongs to ST's high-reliability TVS portfolio, engineered specifically for demanding automotive and industrial applications where low leakage, high-temperature stability, and IEC 61000-4-2 Level 4 compliance are mandatory.

FAQ

What is the maximum clamping voltage of SMM4F5.0A-TR under a 10/1000 µs surge?

The maximum clamping voltage is 9.2 V at a peak pulse current of 43.5 A for a 10/1000 µs waveform, measured at 25 °C ambient. This value increases with junction temperature due to the 5.7 × 10⁻⁴/°C temperature coefficient (αT), reaching approximately 10.1 V at 125 °C junction temperature.

Does SMM4F5.0A-TR support bidirectional surge protection?

No, SMM4F5.0A-TR is a unidirectional TVS diode, intended for protection on positive-only DC rails such as 5 V power supplies. It conducts only when the cathode voltage exceeds the anode by more than the breakdown threshold; reverse polarity events require a separate device or a bidirectional variant like SMM4F5.0CA-TR.

What PCB footprint does SMM4F5.0A-TR require?

SMM4F5.0A-TR uses the STmite Flat package with recommended footprint dimensions of 2.04 mm × 0.85 mm pad length and 0.75 mm pad width (per side), matching IPC7531 guidelines. Thermal performance is optimized with ≥2.8 cm² total copper area under both leads, achieving Rth(j-a) ≤ 2.5 °C/W on FR4 boards.

Is SMM4F5.0A-TR compliant with lead-free soldering processes?

Yes, SMM4F5.0A-TR features matte tin-plated leads and is qualified for lead-free reflow per J-STD-020 MSL Level 1, with a maximum peak temperature of 260 °C for 10 seconds. The recommended profile includes ramp-up ≤3 °C/s, soak at 150–200 °C for 60–90 s, and peak at 240–245 °C for ≤10 s.