onsemi 1SMB17CAT3

Overview

1SMB17CAT3 from ON Semiconductor is a bidirectional 600 W transient voltage suppressor (TVS) diode designed for parallel overvoltage protection of sensitive electronics. It features a 17 V working peak reverse voltage (VRWM), 20.9 V maximum clamping voltage (VC) at 21.7 A peak pulse current, and sub-1 ns response time. It is used in power supply input stages to suppress ESD and lightning-induced surges.

For engineers reviewing the 1SMB17CAT3 datasheet, pinout, applications, or equivalent options, key selection criteria include VRWM ≥ circuit operating voltage, VC margin relative to IC absolute maximum ratings, I_PP capability under defined surge waveforms (10/1000 µs), and UL 497B recognition for isolated loop protection compliance.

Technical Context

The 1SMB17CAT3 operates as a bidirectional Zener-based TVS, conducting symmetrically above ±V_BR (~18.9 V min) to clamp transients. Its low zener impedance and fast turn-on (<1 ns) enable effective suppression of ESD (Class 3, >16 kV HBM) and 600 W 1 ms surges without thermal runaway under single-event conditions.

It is rated for –65 °C to +150 °C junction temperature, with thermal resistance from junction to lead (R_JL) of 40 °C/W and junction-to-ambient (R_JA) of 226 °C/W on FR-4 board. The device uses a void-free Surmetic SMB (DO-214AA) package optimized for surface-mount reliability and solderability at 260 °C for 10 s.

Key Specifications

Pinout & Package

Package: SMB (DO-214AA), case outline 403A–03 - Surface-mount plastic package with modified L-bend leads, void-free thermosetting molding compound, and corrosion-resistant, solderable terminations.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBJ17CA and 1.5SMC17CA, the 1SMB17CAT3 offers UL 497B certification in the compact SMB footprint-critical for space-constrained industrial and medical designs requiring safety-agency approval-while delivering matched clamping performance to the SMBJ series and lower surge rating than the SMC variant.

Availability

1SMB17CAT3 is available at Aetrix Electronics and suitable for industrial power supplies, automotive control units, medical sensor interfaces, and telecom line cards requiring stable component supply and certified surge protection.

Supply support for 1SMB17CAT3 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

ON Semiconductor (now part of onsemi) is a global semiconductor supplier specializing in energy-efficient power, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The 1SMB17CAT3 belongs to the SMB-series transient voltage suppressor family, engineered for high-reliability, surface-mount overvoltage protection in harsh environments-designed specifically for applications demanding UL recognition, fast response, and robust 600 W surge handling.

FAQ

What is the working peak reverse voltage (VRWM) of the 1SMB17CAT3?

The 1SMB17CAT3 has a working peak reverse voltage (VRWM) of 17 V, meaning it remains non-conductive up to this DC or peak AC voltage level. This parameter is critical for selecting the correct TVS-VRWM must be equal to or greater than the normal operating voltage of the circuit being protected to avoid leakage or false triggering. The 1SMB17CAT3 is therefore suited for 12–15 V nominal systems with transient headroom.

What is the maximum clamping voltage (VC) of the 1SMB17CAT3 and at what current is it specified?

The 1SMB17CAT3 has a maximum clamping voltage (V_C) of 27.6 V, measured at a peak pulse current (I_PP) of 21.7 A using the standard 10/1000 µs waveform. This value represents the worst-case voltage seen by downstream components during a surge event. Engineers use this figure to verify that protected ICs remain within their absolute maximum voltage ratings-e.g., a 30 V-rated MOSFET would retain safe margin with the 1SMB17CAT3.

Is the 1SMB17CAT3 unidirectional or bidirectional, and how does that affect its usage?

The 1SMB17CAT3 is a bidirectional TVS diode, meaning it clamps voltage transients equally in both polarities-ideal for protecting AC lines, differential buses (e.g., CAN, RS-485), or floating DC rails where polarity reversal or common-mode surges may occur. Unlike unidirectional variants (e.g., 1SMB17AT3), the 1SMB17CAT3 requires no orientation during placement and provides symmetrical protection without external biasing, simplifying layout and reducing BOM count.

Does the 1SMB17CAT3 have UL recognition, and for which standard?

Yes, the 1SMB17CAT3 carries UL recognition under UL 497B (File #116110, category QVGV2) for isolated loop circuit protection. This certification confirms successful completion of rigorous tests including strike voltage breakdown, endurance conditioning, dielectric withstand, and discharge validation-going beyond basic flammability requirements. This makes the 1SMB17CAT3 suitable for safety-critical industrial and medical applications where agency approval is mandatory.

What package type does the 1SMB17CAT3 use, and what are its key mechanical features?

The 1SMB17CAT3 uses the SMB (DO-214AA) package, also known as case 403A–03. Key mechanical features include void-free transfer-molded thermosetting plastic construction, corrosion-resistant and readily solderable leads with modified L-bend geometry for enhanced pad contact, and compatibility with standard reflow profiles-including 260 °C for 10 seconds. Its compact 4.06 mm × 3.30 mm footprint supports high-density PCB layouts in space-constrained applications.