Vishay General Semiconductor - Diodes Division SMBJ40AHM3_A/H

Overview

SMBJ40AHM3_A/H from Vishay General Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in SMB (DO-214AA) package, designed for robust overvoltage protection of DC power rails and signal lines. It features a 40 V stand-off voltage (V_WM), 44.4–49.1 V breakdown voltage (V_BR) at 1 mA, 64.5 V maximum clamping voltage (V_C) at 9.3 A peak pulse current, and 600 W peak pulse power rating with 10/1000 µs waveform - deployed in industrial motor drives, automotive body control modules, and industrial sensor interfaces.

For engineers reviewing the SMBJ40AHM3_A/H datasheet, SMBJ40AHM3_A/H pinout, SMBJ40AHM3_A/H application, or SMBJ40AHM3_A/H equivalent, this page delivers verified electrical parameters, AEC-Q101 qualification status, thermal resistance (R_θJA = 100 °C/W), halogen-free RoHS compliance, and real-world clamping performance data essential for surge immunity validation in 24 V and 48 V systems.

Technical Context

This TVS diode operates as a unidirectional clamping device: reverse-biased during normal operation, it remains high-impedance until transient voltage exceeds V_WM (40 V), then avalanches to limit voltage across protected circuitry. Its glass-passivated junction ensures stable breakdown behavior and low leakage (<1.0 µA at V_WM).

Engineered for repetitive surge events, SMBJ40AHM3_A/H sustains 600 W peak pulse power under 10/1000 µs waveform at 0.01% duty cycle, with thermal resistance R_θJL = 20 °C/W enabling effective heat transfer to PCB copper pads. It meets MSL Level 1 per J-STD-020 and supports lead-free reflow up to 260 °C peak.

Key Specifications

Pinout & Package

Package: SMB (DO-214AA), surface-mount, halogen-free, RoHS-compliant, matte tin-plated leads. Cathode indicated by band; polarity critical for unidirectional operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBJ40AHM3_A/H, SMBJ40AHE3_A/H offers identical protection performance without halogen-free assurance or automotive qualification, while SMAJ40AHE3_A/H trades 33% lower pulse power and inferior thermal performance for reduced PCB area - making SMBJ40AHM3_A/H the optimal choice for AEC-Q101-compliant, high-energy industrial and automotive deployments.

Availability

SMBJ40AHM3_A/H is available at Aetrix Electronics and suitable for industrial motor drives, automotive body control modules, and telecom power interfaces requiring stable component supply, long-term lifecycle support, and traceable halogen-free sourcing.

Supply support for SMBJ40AHM3_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 SMBJ series is engineered for high-energy transient suppression in harsh environments - targeting automotive, industrial automation, and communications infrastructure where robustness and AEC-Q101 compliance are mandatory.

FAQ

What is the clamping voltage of SMBJ40AHM3_A/H at its rated peak pulse current?

The SMBJ40AHM3_A/H has a maximum clamping voltage (V_C) of 64.5 V at its rated peak pulse current (I_PPM) of 9.3 A, measured using the standardized 10/1000 µs double-exponential waveform. This value ensures protected circuits experience no more than 64.5 V during surge events, directly supporting design margin calculations for 48 V system components. The SMBJ40AHM3_A/H datasheet confirms this parameter under "Electrical Characteristics" Table 1.

Is SMBJ40AHM3_A/H qualified for automotive applications?

Yes, SMBJ40AHM3_A/H is AEC-Q101 qualified, as confirmed by Vishay's ordering code structure (HM3 suffix denotes halogen-free + AEC-Q101) and documentation in the "Mechanical Data" section. This qualification covers stress tests including temperature cycling, high-temperature reverse bias, and ESD, making SMBJ40AHM3_A/H suitable for under-hood and body electronics such as BCMs and lighting control units.

What is the standoff voltage (V_WM) and why is it critical for SMBJ40AHM3_A/H selection?

The standoff voltage (V_WM) of SMBJ40AHM3_A/H is 40 V - the maximum continuous reverse voltage it can block without entering breakdown. This parameter must exceed the normal operating voltage of the protected line (e.g., 36 V max for a 48 V nominal rail) to prevent leakage or thermal runaway. Selecting SMBJ40AHM3_A/H for 48 V systems ensures ≥20% margin above typical DC operating range while retaining fast response to transients exceeding 40 V.

Does SMBJ40AHM3_A/H have halogen-free construction?

Yes, SMBJ40AHM3_A/H uses halogen-free molding compound and matte tin-plated leads, meeting IEC 61249-2-21 and JEDEC JS709C requirements. The "HM3" suffix explicitly denotes halogen-free, RoHS-compliant, and AEC-Q101-qualified construction - verified in Vishay's ordering information table and "Mechanical Data" section of document 88392.

How does the thermal resistance of SMBJ40AHM3_A/H impact PCB layout?

SMBJ40AHM3_A/H has a typical junction-to-ambient thermal resistance (R_θJA) of 100 °C/W when mounted on 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal. To maintain T_J ≤ 150 °C under sustained 5.0 W power dissipation, designers must allocate ≥250 mm² of internal/external copper pour per pad and avoid narrow traces. This requirement directly influences thermal relief design and layer stack-up decisions in automotive and industrial PCBs using SMBJ40AHM3_A/H.