onsemi SMF150AT1

Overview

SMF150AT1 from onsemi is a unidirectional transient voltage suppressor (TVS) diode designed for overvoltage protection in DC power rails and signal lines. It features a 150 V working peak reverse voltage (VRWM), 243 A maximum peak pulse current (IPP), 225 V maximum clamping voltage (VC) at IPP, and <1 ns response time. It is used in industrial power supplies, telecom infrastructure interfaces, and automotive body control modules where robust ESD and surge immunity is required.

For engineers reviewing the SMF150AT1 datasheet, pinout, applications, or equivalent options, this page delivers verified electrical specs, SOD−123FL package details, real-world use cases, and validated alternative parts - all aligned to ON Semiconductor's official SMF5.0AT1 Series documentation (Rev. 0, March 2003).

Technical Context

The SMF150AT1 operates as a Zener-based unidirectional TVS, conducting only in reverse breakdown above VRWM = 150 V to clamp transients. Its clamping behavior is defined by VC = 225 V at IPP = 243 A under the 10/1000 µs waveform, with low zener impedance ensuring stable voltage limiting during high-energy surges.

It meets IEC61000−4−2 Level 4 (±16 kV contact / ±15 kV air) and IEC61000−4−4 (40 A, 5/50 ns) ESD/surge standards. Thermal performance is rated for TJ = −55°C to +150°C, with RθJA = 325°C/W on FR-4 using the recommended SOD−123FL footprint.

Key Specifications

Pinout & Package

SOD−123FL is a 2-terminal surface-mount plastic package with cathode indicated by a polarity band. Mounting position is unrestricted; qualified for reflow up to 260°C (MSL 1). Lead finish is 100% matte tin.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMF150AT1, SMBJ150A offers 3.4× higher peak power but requires 3.5× more board area; 1.5SMC150A matches power rating but sacrifices thermal efficiency and miniaturization - making SMF150AT1 optimal for space- and weight-sensitive designs needing certified 175 W surge handling.

Availability

SMF150AT1 is available at Aetrix Electronics and suitable for industrial power supplies, telecom interface protection, and automotive body control modules requiring stable component supply and long-term obsolescence management.

Supply support for SMF150AT1 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 consumer markets.

The SMF5.0AT1 Series was developed to deliver high-surge-capable, miniature TVS protection for space-constrained DC power and signal lines - targeting cost-sensitive, high-volume applications where reliability and standardization matter.

FAQ

What is the clamping voltage of SMF150AT1 at its rated peak pulse current?

The SMF150AT1 has a maximum clamping voltage (VC) of 225 V when subjected to its rated peak pulse current (IPP) of 243 A under the 10/1000 µs waveform. This value is guaranteed per the official ON Semiconductor datasheet (SMF5.0AT1/D, Rev. 0) and defines the upper voltage limit imposed on protected circuitry during worst-case surge events. Designers must ensure downstream components tolerate ≤225 V transient exposure.

Is SMF150AT1 unidirectional or bidirectional, and how does that affect circuit placement?

SMF150AT1 is a unidirectional TVS diode, meaning it conducts only in reverse bias above VRWM = 150 V and blocks forward current like a rectifier. It must be placed with cathode toward the protected line and anode to ground or return path. Unlike bidirectional devices, it cannot suppress positive-going transients on grounded signals - correct polarity alignment is mandatory, as confirmed by the cathode band marking on the SOD−123FL package.

What is the maximum operating temperature range for SMF150AT1?

The SMF150AT1 is rated for an operating and storage temperature range of −55°C to +150°C, as specified in the Absolute Maximum Ratings table of the ON Semiconductor datasheet. Its junction-to-ambient thermal resistance (RθJA = 325°C/W) assumes use of the recommended SOD−123FL footprint on FR-4. At TA = 125°C, derating reduces its 175 W peak pulse capability to approximately 60% - critical for under-hood automotive or enclosed industrial environments.

Does SMF150AT1 meet IEC61000−4−2 and IEC61000−4−4 compliance out-of-the-box?

Yes - the SMF150AT1 is characterized to meet IEC61000−4−2 Level 4 (±16 kV contact discharge) and IEC61000−4−4 (40 A, 5/50 ns burst) requirements per the manufacturer's test data. These ratings are intrinsic to its Zener structure and packaging; no external circuitry is needed to achieve compliance. However, system-level validation remains essential, as PCB layout, grounding, and proximity to other components influence actual immunity performance.

What is the leakage current specification for SMF150AT1 at its working voltage?

At its working peak reverse voltage (VRWM) of 150 V and TA = 25°C, the SMF150AT1 exhibits a maximum reverse leakage current (IR) of 1 µA. This ultra-low leakage ensures minimal power loss in always-on or battery-backed systems and prevents loading errors in high-impedance sensing circuits - a key advantage over higher-leakage alternatives like certain polymer-based TVS devices.