Vishay General Semiconductor - Diodes Division SM6T18CAHE3_A/H

Overview

SM6T18CAHE3_A/H from Vishay General Semiconductor is a bidirectional transient voltage suppressor (TVS) diode in SMB (DO-214AA) package, rated for 18 V standoff voltage (VWM), 25.2 V max clamping voltage at 24 A peak pulse current (10/1000 μs), and 600 W peak pulse power. It provides robust ESD and surge protection for automotive sensor signal lines, I/O interfaces, and MOSFET gate drivers.

For engineers reviewing the SM6T18CAHE3_A/H datasheet, SM6T18CAHE3_A/H pinout, SM6T18CAHE3_A/H application, or SM6T18CAHE3_A/H equivalent, key selection criteria include bidirectional clamping behavior, AEC-Q101 qualification, 150 °C junction temperature rating, low clamping ratio (1.40), and compatibility with automated SMT placement on standard PCB pads.

Technical Context

The SM6T18CAHE3_A/H operates as a silicon avalanche diode with symmetrical breakdown in both polarities, enabling protection of AC-coupled or differential signal paths without polarity concerns. Its glass-passivated junction ensures stable leakage (<1 μA at 15.3 V) and repeatable clamping performance across temperature.

Designed for transient suppression per IEC 61000-4-2 (ESD) and IEC 61000-4-5 (surge), it delivers 600 W peak pulse power under 10/1000 μs waveform with thermal resistance R_θJA = 100 °C/W and R_θJL = 20 °C/W, supporting reliable operation up to +150 °C junction temperature.

Key Specifications

Pinout & Package

Package: SMB (DO-214AA), surface-mount, bidirectional device with no polarity marking. Dimensions: 4.57 mm × 3.94 mm × 2.20 mm (L × W × H); matte tin-plated leads, J-STD-002 solderable.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ18CA and 1.5KE18CA, the SM6T18CAHE3_A/H uniquely combines AEC-Q101 qualification, 600 W pulse rating, and SMB package suitability for automated SMT-making it optimal for new automotive and industrial SMT designs where reliability, power handling, and manufacturability are jointly critical.

Availability

SM6T18CAHE3_A/H is available at Aetrix Electronics and suitable for automotive sensor protection, industrial I/O interface hardening, and MOSFET gate driver safeguarding requiring stable component supply and long-term lifecycle support.

Supply support for SM6T18CAHE3_A/H 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

Vishay General Semiconductor is a global leader in discrete semiconductors, specializing in diodes, rectifiers, MOSFETs, and protection devices with emphasis on reliability, efficiency, and application-specific optimization.

The SM6T Series is designed specifically for robust transient voltage suppression in automotive, industrial, and consumer electronics-balancing high pulse power, low clamping, and AEC-Q101 compliance in compact surface-mount packages.

FAQ

What does the "CA" suffix indicate in SM6T18CAHE3_A/H?

The "CA" suffix denotes a bidirectional configuration: the SM6T18CAHE3_A/H conducts symmetrically in both forward and reverse directions, making it suitable for protecting AC signals, differential buses, or ungrounded circuits. Unlike unidirectional variants (e.g., SM6T18A), it has no cathode band marking and exhibits identical V_BR and V_C characteristics in either polarity. This behavior is confirmed in the Vishay SM6T datasheet revision 09-Jan-2024, page 1.

Is SM6T18CAHE3_A/H qualified for automotive applications?

Yes, SM6T18CAHE3_A/H is AEC-Q101 qualified, as explicitly stated in the Vishay ordering information table (page 2) and mechanical data section. The "HE3" suffix indicates RoHS-compliant and AEC-Q101 qualified construction. This qualification covers stress tests including temperature cycling, high-temperature reverse bias, and accelerated life testing-enabling use in automotive ECUs, ADAS sensors, and body electronics per SM6T Series documentation.

What is the clamping voltage of SM6T18CAHE3_A/H at its rated peak pulse current?

The SM6T18CAHE3_A/H has a maximum clamping voltage (V_C) of 25.2 V at 24 A peak pulse current with a 10/1000 μs waveform, per the Electrical Characteristics table on page 2 of the Vishay SM6T datasheet. This value is measured under standardized conditions (TA = 25 °C, mounted on 0.2" × 0.2" copper pads) and defines the upper voltage limit imposed on protected circuitry during surge events.

How does the SMB (DO-214AA) package of SM6T18CAHE3_A/H compare to SMA in thermal performance?

The SMB package of SM6T18CAHE3_A/H offers lower thermal resistance than SMA: R_θJL = 20 °C/W (vs. ~30–35 °C/W for SMA), enabling more efficient heat transfer to PCB copper. Its larger pad area (0.2" × 0.2") also improves power dissipation during repetitive pulses. These advantages are documented in the Thermal Characteristics table (page 2) and Package Outline Dimensions (page 4) of the Vishay SM6T datasheet.

Does SM6T18CAHE3_A/H require derating above ambient temperature?

Yes, SM6T18CAHE3_A/H requires derating above TA = 25 °C, as shown in Figure 2 ("Pulse Power or Current vs. Initial Junction Temperature") of the Vishay SM6T datasheet. Peak pulse power decreases linearly to zero at TJ = +150 °C, with a defined derating curve. For example, at TA = 85 °C, maximum allowable PPPM drops to approximately 420 W-critical for thermal design validation in enclosed automotive or industrial enclosures.