Vishay General Semiconductor - Diodes Division SMBJ15CAHM3_A/H

Overview

SMBJ15CAHM3_A/H from Vishay General Semiconductor is a bidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMB (DO-214AA) package, designed for clamping voltage transients on power and signal lines. It features a 15 V standoff voltage (V_WM), 24.4 V maximum clamping voltage (V_C) at 24.6 A peak pulse current (I_PPM), and 600 W peak pulse power (10/1000 µs waveform), commonly deployed to protect MOSFETs and sensor interfaces in industrial motor drives.

For engineers reviewing the SMBJ15CAHM3_A/H datasheet, SMBJ15CAHM3_A/H pinout, SMBJ15CAHM3_A/H application, or SMBJ15CAHM3_A/H equivalent, key selection criteria include bidirectional clamping capability, low clamping ratio (V_C/V_WM = 1.63), AEC-Q101 qualification status, halogen-free RoHS compliance (HM3 suffix), and thermal resistance (R_θJA = 100 °C/W) under standard PCB pad layout.

Technical Context

This TVS diode operates symmetrically in both directions due to its bidirectional construction, enabling protection of AC-coupled or differential signal paths without polarity concerns. Its glass-passivated junction ensures stable breakdown behavior and low leakage (<1.0 µA at V_WM), while the 10/1000 µs surge rating reflects standardized lightning and switching transient immunity per ANSI/IEEE C62.35.

The device is rated for continuous operation from −55 °C to +150 °C junction temperature, with derating applied above 25 °C ambient per Fig. 2. Its MSL Level 1 moisture sensitivity and 260 °C reflow compatibility support automated SMT assembly without pre-baking.

Key Specifications

Pinout & Package

Package: SMB (DO-214AA), surface-mount, halogen-free, RoHS-compliant, MSL Level 1, matte tin-plated terminals solderable per J-STD-002.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBJ15CAHM3_A/H, SMBJ15CAHE3_A/H offers identical protection performance but lacks halogen-free assurance, while SMAJ15CAHM3_A/H trades 33 % lower surge capacity and higher thermal resistance for 30 % smaller PCB area-neither is pin-compatible due to differing package outlines (SMB vs. SMA).

Availability

SMBJ15CAHM3_A/H is available at Aetrix Electronics and suitable for industrial motor drives, automotive body control modules, and telecom power supplies requiring stable component supply with halogen-free and AEC-Q101-compliant sourcing.

Supply support for SMBJ15CAHM3_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 and application-specific validation.

The SMBJ series targets high-energy transient suppression in harsh environments, with design focus on automotive-grade robustness, industrial surge immunity, and seamless SMT integration for high-volume manufacturing.

FAQ

What is the clamping voltage of SMBJ15CAHM3_A/H at its rated peak pulse current?

The SMBJ15CAHM3_A/H has a maximum clamping voltage (V_C) of 24.4 V when subjected to its rated peak pulse current (I_PPM) of 24.6 A under the standard 10/1000 µs waveform. This value is measured per ANSI/IEEE C62.35 and ensures downstream components see no more than 24.4 V during surge events. The SMBJ15CAHM3_A/H maintains this clamping performance across its full operating temperature range (−55 °C to +150 °C).

Is SMBJ15CAHM3_A/H suitable for automotive applications?

Yes, SMBJ15CAHM3_A/H is AEC-Q101 qualified, as indicated by the "HM3" suffix, confirming its suitability for automotive applications including body electronics, infotainment power rails, and sensor interfaces. It meets stringent requirements for thermal cycling, humidity resistance, and surge endurance. The SMBJ15CAHM3_A/H is specifically rated for junction temperatures up to +150 °C and supports reflow profiles up to 260 °C, aligning with automotive PCB assembly standards.

How does the bidirectional configuration of SMBJ15CAHM3_A/H affect circuit layout?

The SMBJ15CAHM3_A/H has no polarity marking and conducts identically in both directions, eliminating orientation constraints during placement. This simplifies PCB layout by removing the need for cathode band alignment, reducing assembly errors and enabling use on AC-coupled or differential lines (e.g., RS-485, CAN FD). Unlike unidirectional TVS diodes, the SMBJ15CAHM3_A/H requires no consideration of signal polarity or ground reference direction.

What is the standoff voltage (V_WM) and why is it critical for SMBJ15CAHM3_A/H selection?

The standoff voltage (V_WM) of SMBJ15CAHM3_A/H is 15 V - the maximum continuous reverse voltage it can block without entering avalanche conduction. Selecting a V_WM ≥110 % of the normal operating voltage prevents false triggering during ripple or tolerance excursions. For a 12 V automotive system, the SMBJ15CAHM3_A/H provides a 25 % margin, ensuring reliable operation while maintaining low leakage (<1.0 µA) and minimal power loss.

Does SMBJ15CAHM3_A/H require heatsinking in typical applications?

In most applications using standard 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal, SMBJ15CAHM3_A/H does not require additional heatsinking due to its R_θJA of 100 °C/W and low average power dissipation (P_D = 5.0 W). However, under repeated surge conditions or elevated ambient temperatures (>70 °C), thermal simulation is recommended. The SMBJ15CAHM3_A/H's MSL Level 1 rating confirms compatibility with standard reflow profiles without pre-bake.