Vishay General Semiconductor - Diodes Division SMAJ90AHM3_A/H

Overview

SMAJ90AHM3_A/H from Vishay General Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, designed for clamping voltage transients on power and signal lines. It features a 90 V standoff voltage (V_WM), 100–111 V breakdown range (V_BR at 1 mA), 146 V maximum clamping voltage (V_C) at 2.1 A peak pulse current, and 400 W peak pulse power rating (10/1000 μs waveform). It is used to protect MOSFETs, ICs, and sensor interfaces in automotive and industrial power supplies.

For engineers reviewing the SMAJ90AHM3_A/H datasheet, SMAJ90AHM3_A/H pinout, SMAJ90AHM3_A/H application, or SMAJ90AHM3_A/H equivalent, key selection criteria include its AEC-Q101 qualification, halogen-free RoHS-compliant construction (HM3 suffix), low thermal resistance (R_θJL = 30 °C/W), and 150 °C max junction temperature - critical for under-hood automotive electronics and high-reliability industrial control systems.

Technical Context

This unidirectional TVS diode operates as a voltage-clamping protection device that enters avalanche conduction when reverse voltage exceeds its breakdown threshold. Its glass-passivated junction ensures stable leakage performance and fast response time (<1 ps), while the SMA package supports automated SMT placement and meets MSL level 1 (260 °C reflow peak).

The device delivers 400 W peak pulse power up to 78 V and derates to 300 W above 78 V per JEDEC standards. With 1.0 μA max reverse leakage at 90 V and 146 V clamping voltage at 2.1 A, it provides precise overvoltage limiting for 12 V/24 V/48 V DC bus lines without interfering with normal operation.

Key Specifications

Pinout & Package

Package: SMA (DO-214AC), surface-mount, single-ended unidirectional configuration with cathode band marking. Dimensions: 4.50 mm × 2.79 mm × 2.29 mm (L × W × H); terminals are matte tin-plated, solderable per J-STD-002 and JESD 22-B102.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ90AHM3_A/H, SMAJ90AHE3_A/H offers identical protection performance with relaxed material compliance, while SMCJ90A-H trades compact size for significantly higher surge capacity - enabling tiered design strategies based on threat level and layout constraints.

Availability

SMAJ90AHM3_A/H is available at Aetrix Electronics and suitable for automotive electronic control units, industrial programmable logic controllers, and telecom power supply designs requiring stable component supply, long-term lifecycle support, and AEC-Q101-qualified surge protection.

Supply support for SMAJ90AHM3_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, and protection devices with emphasis on reliability, efficiency, and application-specific validation.

The SMAJ series is engineered for robust transient suppression in harsh environments, targeting automotive, industrial, and telecom applications where consistent clamping performance and AEC-Q101 compliance are mandatory.

FAQ

What is the maximum clamping voltage of the SMAJ90AHM3_A/H under standard surge conditions?

The SMAJ90AHM3_A/H has a maximum clamping voltage (V_C) of 146 V at 2.1 A peak pulse current (I_PPM) using the 10/1000 μs waveform. This value is measured per JEDEC standards and defines the upper voltage limit imposed on protected circuitry during transient events. The SMAJ90AHM3_A/H maintains this clamping performance across its full operating temperature range and after repeated surge exposures, making it suitable for mission-critical automotive and industrial applications.

Is SMAJ90AHM3_A/H qualified for automotive use?

Yes, SMAJ90AHM3_A/H is AEC-Q101 qualified, as confirmed by Vishay's ordering code suffix "HM3" and documentation in datasheet 88390. This qualification covers stress tests including high-temperature operating life, temperature cycling, and surge immunity - validating its suitability for under-hood and chassis-mounted automotive electronics. The SMAJ90AHM3_A/H is explicitly designated for automotive applications in Vishay's official ordering information and mechanical data tables.

How does the HM3 suffix differ from E3 or HE3 in the SMAJ90A family?

The HM3 suffix on SMAJ90AHM3_A/H indicates halogen-free, RoHS-compliant, and AEC-Q101-qualified construction. In contrast, E3 denotes RoHS-compliant only (commercial grade), and HE3 adds AEC-Q101 qualification but retains brominated flame retardants. The HM3 variant satisfies strict environmental mandates from global OEMs, especially in Europe and China, without sacrificing electrical or thermal performance - all three share identical V_WM, V_BR, and V_C specifications.

What is the thermal resistance from junction to lead (R_θJL) for SMAJ90AHM3_A/H?

The SMAJ90AHM3_A/H has a typical junction-to-lead thermal resistance (R_θJL) of 30 °C/W, as specified in the Thermal Characteristics table of Vishay's datasheet 88390. This low value enables efficient heat transfer from the silicon die to the PCB copper pads via the leads, supporting reliable operation at full power dissipation without external heatsinking. The R_θJL value is validated under standard mounting conditions (0.2" × 0.2" copper pads per terminal) and is critical for thermal design in enclosed automotive modules.

Can SMAJ90AHM3_A/H be used in bidirectional signal line protection?

No, SMAJ90AHM3_A/H is a unidirectional TVS diode, indicated by the "A" (not "CA") suffix and presence of a cathode band. It conducts only in reverse bias and blocks forward current beyond ~3.5 V. For bidirectional protection - such as on RS-485, CAN, or USB data lines - a bidirectional variant like SMAJ90CAHM3_A/H must be used. Using SMAJ90AHM3_A/H on AC-coupled or symmetrical signal paths would result in unintended forward conduction and potential circuit malfunction.