Vishay General Semiconductor - Diodes Division SMCJ33AHE3_A/I

Overview

SMCJ33AHE3_A/I from Vishay General Semiconductor is a unidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMC (DO-214AB) package, designed for high-energy surge protection with 33 V standoff voltage, 53.3 V clamping voltage at 28.1 A peak pulse current, and 1500 W peak pulse power rating. It protects MOSFETs, ICs, and sensor signal lines against inductive switching transients and lightning-induced surges in automotive and industrial power electronics.

For engineers reviewing the SMCJ33AHE3_A/I datasheet, SMCJ33AHE3_A/I pinout, SMCJ33AHE3_A/I application, or SMCJ33AHE3_A/I equivalent, key selection criteria include its AEC-Q101 qualification, 1500 W 10/1000 μs surge capability, 33 V working voltage, low 0.1 %/°C V_BR temperature coefficient, and compatibility with automated SMT assembly on standard PCB pad layouts.

Technical Context

This TVS diode operates as a unidirectional clamping device with a reverse standoff voltage (V_WM) of 33 V and a minimum breakdown voltage (V_BR) of 36.7 V at 1 mA test current. Its fast response time and low incremental surge resistance enable effective suppression of transient events up to 1500 W under standardized 10/1000 μs waveform conditions.

The device features glass passivated junction construction, meets MSL Level 1 per J-STD-020, and is rated for operating junction temperatures from –55 °C to +150 °C. Its matte tin-plated leads comply with J-STD-002 and JESD 22-B102 solderability standards and JESD 201 Class 2 whisker resistance.

Key Specifications

Pinout & Package

Package: SMC (DO-214AB), surface-mount, low-profile case with cathode band marking. Dimensions: 7.75 mm × 6.22 mm × 2.62 mm (L × W × H); 0.305" × 0.246" × 0.103". Mounting requires 8.0 mm × 8.0 mm copper pads per terminal per Vishay recommended layout.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ33AHE3_A/I and SMCJ33CAHE3_A/I, the SMCJ33AHE3_A/I delivers superior energy handling in a robust SMC package while maintaining AEC-Q101 qualification-making it the preferred choice for automotive and industrial DC power line protection where 1500 W surge immunity and thermal reliability are mandatory.

Availability

SMCJ33AHE3_A/I is available at Aetrix Electronics and suitable for automotive power distribution, industrial sensor interfaces, telecom DC inputs, and consumer power adapter outputs requiring stable component supply and long-term lifecycle support.

Supply support for SMCJ33AHE3_A/I 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 performance.

The SMCJ series is engineered for high-energy transient suppression in harsh environments, targeting automotive, industrial, and telecom systems where robustness against ISO 7637-2, IEC 61000-4-5, and lightning surges is essential.

FAQ

What is the clamping voltage of SMCJ33AHE3_A/I at its rated peak pulse current?

The SMCJ33AHE3_A/I has a maximum clamping voltage (V_C) of 53.3 V at its rated peak pulse current (I_PPM) of 28.1 A under the standard 10/1000 μs waveform. This value is measured per ANSI/IEEE C62.35 and defines the upper voltage limit imposed on protected circuitry during a full-power surge event. The SMCJ33AHE3_A/I maintains this clamping performance across its qualified temperature range and after repeated surge exposures per AEC-Q101 stress testing.

Is SMCJ33AHE3_A/I suitable for automotive applications?

Yes, SMCJ33AHE3_A/I is AEC-Q101 qualified and explicitly designated for automotive use with the "HE3" suffix. It meets stress test requirements for temperature cycling, high-temperature operating life, and mechanical shock. Its 1500 W surge rating, –55 °C to +150 °C operating range, and MSL Level 1 reflow compatibility make SMCJ33AHE3_A/I appropriate for engine control units, body electronics, and ADAS power domains where load dump and jump-start transients occur.

How does the SMCJ33AHE3_A/I differ from the bidirectional SMCJ33CAHE3_A/I?

The SMCJ33AHE3_A/I is unidirectional and clamps only when voltage exceeds 33 V in reverse bias, with the cathode marked by a band. The SMCJ33CAHE3_A/I is bidirectional, providing symmetrical clamping for both polarities-ideal for AC or floating signals. Both share identical V_WM (33 V), V_BR, PPPM (1500 W), and package, but SMCJ33AHE3_A/I offers lower capacitance and is optimized for DC rail protection where polarity is fixed.

What is the thermal resistance of SMCJ33AHE3_A/I, and how does it affect PCB layout?

The SMCJ33AHE3_A/I has a typical junction-to-ambient thermal resistance (R_θJA) of 75 °C/W and junction-to-lead (R_θJL) of 15 °C/W. To maintain safe junction temperatures under sustained power dissipation, PCB layout must use minimum 8.0 mm × 8.0 mm copper pads per terminal as specified in the Vishay datasheet. Reducing pad size or omitting thermal vias increases R_θJA, risking thermal runaway during repetitive surges or elevated ambient conditions.

Does SMCJ33AHE3_A/I require derating at elevated ambient temperatures?

Yes, SMCJ33AHE3_A/I must be derated above 25 °C ambient per Figure 2 in the Vishay datasheet. At 85 °C ambient, its peak pulse power drops to approximately 75 % of 1500 W (1125 W), and at 125 °C, it falls to ~45 % (675 W). This derating applies to both single-pulse and repetitive surge conditions. Designers must verify worst-case thermal environment and apply appropriate safety margins-especially in under-hood automotive or enclosed industrial enclosures.