Vishay General Semiconductor - Diodes Division SMAJ550HE3_ALL

Overview

SMAJ550HE3_ALL from Vishay General Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, rated for 550 V breakdown voltage (V_BR), 495 V stand-off voltage (V_WM), and 300 W peak pulse power (P_PPM). It protects MOSFETs, ICs, and sensor signal lines against inductive switching transients and lightning surges in industrial and automotive power electronics.

For engineers reviewing the SMAJ550HE3_ALL datasheet, SMAJ550HE3_ALL pinout, SMAJ550HE3_ALL application, or SMAJ550HE3_ALL equivalent, key selection criteria include clamping voltage at 400 mA (760 V), low leakage (<1.0 µA at V_WM), thermal resistance (R_θJA = 120 °C/W), AEC-Q101 qualification eligibility, and compatibility with 10/1000 µs surge waveforms.

Technical Context

This TVS diode operates as a unidirectional clamping device with glass-passivated junction and cathode-band polarity marking. Its 550 V V_BR ensures robust overvoltage protection while maintaining 495 V DC stand-off capability, enabling use across high-voltage bus monitoring and gate driver circuits.

Clamping performance is defined by 760 V maximum at 400 mA (10/1000 µs), with incremental surge resistance contributing to fast response and low overshoot. Thermal design relies on R_θJL = 30 °C/W and R_θJA = 120 °C/W under standard PCB pad layout, supporting operation up to T_J = 150 °C.

Key Specifications

Pinout & Package

Package: SMA (DO-214AC), surface-mount, halogen-free, RoHS-compliant, MSL Level 1 (260 °C peak reflow). Cathode indicated by molded band.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ550HE3_ALL, SMAJ550A-M3/61 offers identical electrical specs but lacks automotive qualification, while SMCJ550A delivers higher surge capacity in a physically larger package-making SMAJ550HE3_ALL optimal for space-constrained, high-reliability industrial or automotive-adjacent designs requiring 300 W clamping.

Availability

SMAJ550HE3_ALL is available at Aetrix Electronics and suitable for industrial motor drives, automotive power modules, telecom base station RF front-end, and renewable energy inverter DC link applications requiring stable component supply, consistent lead-time visibility, and long-term lifecycle support.

Supply support for SMAJ550HE3_ALL 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, thermal performance, and application-specific validation.

The SMAJ series is designed for high-voltage transient suppression in compact surface-mount form factors, targeting industrial automation, automotive subsystems, and infrastructure equipment where space, surge margin, and thermal stability are critical.

FAQ

What is the breakdown voltage specification for SMAJ550HE3_ALL?

The SMAJ550HE3_ALL has a minimum breakdown voltage (V_BR) of 550 V at 100 μA test current, verified per Vishay Document Number 88391. This value defines the threshold at which the device transitions from high-impedance blocking to low-impedance clamping, ensuring reliable protection above its 495 V stand-off voltage. The SMAJ550HE3_ALL maintains this rating across its qualified temperature range and meets JEDEC J-STD-020 MSL Level 1 reflow requirements.

Is SMAJ550HE3_ALL AEC-Q101 qualified?

The SMAJ550HE3_ALL itself is not AEC-Q101 qualified; however, Vishay offers the functionally identical SMAJ550HM3_B variant with full AEC-Q101 qualification for automotive applications. SMAJ550HE3_ALL shares the same electrical characteristics-including 550 V V_BR, 495 V V_WM, and 760 V clamping-but uses the industrial-grade M3 suffix. For automotive underhood deployment, specify the HM3 suffix version instead of SMAJ550HE3_ALL.

What is the clamping voltage of SMAJ550HE3_ALL under standard test conditions?

The SMAJ550HE3_ALL exhibits a maximum clamping voltage (V_C) of 760 V when subjected to a 400 mA, 10/1000 µs surge waveform at 25 °C, as specified in Vishay's official datasheet (Document Number 88391). This value represents the upper voltage limit imposed on protected circuitry during transient events and is measured with the device mounted on standard 0.2" × 0.2" copper pads. V_C increases with ambient temperature and reduced PCB copper area.

Does SMAJ550HE3_ALL have polarity markings, and how is it oriented on the PCB?

Yes, SMAJ550HE3_ALL features a visible cathode band on the SMA (DO-214AC) package body, indicating the cathode terminal. During PCB layout, the cathode must be connected to the lower-potential node (e.g., ground or return path), while the anode connects to the line being protected. Incorrect orientation prevents clamping action and may result in catastrophic failure under overvoltage. The band aligns with standard DO-214AC mechanical drawings and matches Vishay's recommended mounting pad layout.

What is the junction-to-ambient thermal resistance (R_θJA) for SMAJ550HE3_ALL?

The SMAJ550HE3_ALL has a typical junction-to-ambient thermal resistance (R_θJA) of 120 °C/W when mounted on the minimum recommended PCB pad layout per Vishay Document Number 88391. This value assumes 0.2" × 0.2" copper pads per terminal and defines the thermal bottleneck for steady-state power dissipation (2.5 W) and surge duty-cycle limits. For improved thermal performance, designers may increase copper area or add thermal vias-though R_θJA remains dependent on actual board construction.