onsemi SMF110AT1G

Overview

SMF110AT1G from onsemi is a unidirectional transient voltage suppressor (TVS) diode in SOD−123FL package, designed for overvoltage protection of DC power rails and signal lines. It features a 110 V working peak reverse voltage (VRWM), 177 A maximum peak pulse current (IPP), 135 V maximum clamping voltage (VC) at IPP, <1 ns response time, and 175 W peak pulse power (10/1000 µs). It is used in industrial power supplies and telecom interface circuits to absorb ESD and lightning-induced surges.

For engineers reviewing the SMF110AT1G datasheet, pinout, applications, or equivalent options, key selection criteria include clamping voltage margin relative to protected circuit's absolute maximum rating, VRWM alignment with steady-state operating voltage, surge current capability under IEC 61000−4−4 (40 A), and thermal performance in compact SOD−123FL layout.

Technical Context

This TVS operates as a zener-based avalanche clamp, triggered when reverse voltage exceeds its breakdown threshold (VBR = 122–135 V @ IT = 1 mA). Its low dynamic impedance ensures stable clamping during fast transients, and its unidirectional polarity prevents forward conduction during normal operation.

The device complies with IEC 61000−4−2 Level 4 (±16 kV HBM) and IEC 61000−4−4 (40 A, 5/50 ns), and is rated for −55°C to +150°C junction temperature. Its SOD−123FL package delivers 8.45 mm² footprint and 1.0 mm max height, enabling high-density PCB placement near connectors or IC inputs.

Key Specifications

Pinout & Package

SOD−123FL is a 2-terminal surface-mount package with cathode indicated by a polarity band. Mounting orientation is unrestricted; leads are matte tin-plated and qualified for lead-free reflow up to 260°C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBJ110A and 1.5SMC110A, SMF110AT1G offers optimal balance of compact SOD−123FL size, sub-1 ns response, and certified 175 W surge capability-making it preferred for modern high-density, fast-response DC protection where board real estate and timing margins are critical.

Availability

SMF110AT1G is available at Aetrix Electronics and suitable for industrial power supplies, telecom infrastructure equipment, and automotive body control modules requiring stable component supply and long-term lifecycle support.

Supply support for SMF110AT1G 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensors, and connectivity solutions for automotive, industrial, cloud, and medical markets.

The SMF series is part of onsemi's transient voltage suppressor portfolio, engineered specifically for compact, high-speed DC rail and signal-line protection in space-constrained, high-reliability applications.

FAQ

What is the clamping voltage of SMF110AT1G at its rated peak pulse current?

The SMF110AT1G has a maximum clamping voltage (VC) of 135 V when subjected to its rated peak pulse current (IPP) of 177 A under the 10/1000 µs waveform. This value is measured per Figure 2 in the official datasheet and defines the upper voltage limit imposed on protected circuitry during surge events. Maintaining VC below the absolute maximum rating of downstream components is essential for reliable protection using SMF110AT1G.

Is SMF110AT1G unidirectional or bidirectional, and how does that affect its circuit placement?

SMF110AT1G is a unidirectional TVS diode, meaning it conducts only in reverse bias above its breakdown voltage and blocks forward current like a standard rectifier. It must be placed with cathode toward the protected line and anode to ground-reversal would cause forward conduction during normal operation. This polarity-specific behavior makes SMF110AT1G ideal for DC rail protection but unsuitable for AC or bidirectional signal lines without pairing.

Does SMF110AT1G meet IEC 61000−4−2 and IEC 61000−4−4 immunity standards?

Yes, SMF110AT1G is rated for IEC 61000−4−2 Level 4 ESD immunity (>16 kV HBM) and IEC 61000−4−4 electrical fast transient (EFT) immunity at 40 A (5/50 ns). These certifications are explicitly stated in the "Specification Features" section of the SMF5.0AT1 Series datasheet. Designers can rely on SMF110AT1G to satisfy these requirements in end-equipment compliance testing when implemented with proper PCB layout and grounding.

What is the thermal resistance and power derating behavior of SMF110AT1G?

SMF110AT1G in SOD−123FL package has a junction-to-ambient thermal resistance (RθJA) of 325°C/W when mounted on FR-4 with the recommended minimum pad size. Its DC power dissipation is 385 mW at 25°C ambient, derating linearly above that temperature. The device also supports 1000 W peak power for 8/20 µs pulses, but sustained power must stay within derated limits to avoid thermal runaway-critical for continuous surge duty cycles in industrial environments using SMF110AT1G.

Can SMF110AT1G be used in place of SMF100AT1G or SMF120AT1G without circuit redesign?

No-SMF110AT1G is not a drop-in replacement for SMF100AT1G or SMF120AT1G due to differences in VRWM (110 V vs. 100 V or 120 V), VBR (122–135 V vs. 111–123 V or 133–147 V), and clamping voltage. Substituting without verifying compatibility with protected circuit voltage margins may result in either premature clamping (if VRWM too low) or insufficient protection (if VRWM too high). Each variant must be selected based on exact system operating voltage and safety margin requirements for SMF110AT1G integration.