Vishay General Semiconductor - Diodes Division SMAJ54CAHM3_A/H

Overview

SMAJ54CAHM3_A/H from Vishay General Semiconductor is a bidirectional transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, designed for robust overvoltage protection of sensitive electronics. It features a 54 V standoff voltage (V_WM), 60.0–66.3 V breakdown range (V_BR), 87.1 V maximum clamping voltage (V_C) at 4.6 A peak pulse current, and 400 W peak pulse power (10/1000 μs waveform). It is widely deployed to protect MOSFETs, ICs, and sensor signal lines in automotive and industrial power supply interfaces.

For engineers reviewing the SMAJ54CAHM3_A/H datasheet, SMAJ54CAHM3_A/H pinout, SMAJ54CAHM3_A/H application, or SMAJ54CAHM3_A/H equivalent, key selection criteria include bidirectional clamping capability, AEC-Q101 qualification status, thermal resistance (R_θJA = 120 °C/W), low leakage (<1.0 μA at V_WM), and halogen-free RoHS-compliant construction.

Technical Context

This device operates as a voltage-clamped shunt protector: during transients exceeding V_WM, it avalanches rapidly to limit voltage across protected circuitry. Its bidirectional symmetry ensures identical clamping behavior in both polarities, eliminating polarity-sensitive layout constraints.

It delivers 400 W peak pulse power handling up to 78 V and derates to 300 W above that threshold, with thermal performance defined by R_θJA = 120 °C/W and R_θJL = 30 °C/W. The junction temperature range spans –55 °C to +150 °C, supporting under-hood automotive environments.

Key Specifications

Pinout & Package

Package: SMA (DO-214AC), molded plastic case with matte tin-plated leads, MSL Level 1 (260 °C reflow peak), UL 94 V-0 rated compound.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ54CAHE3_A/H, the SMAJ54CAHM3_A/H adds halogen-free construction and AEC-Q101 qualification-critical for under-hood use-while SMBJ54CAHM3_A/H trades compactness for higher surge margin and thermal robustness, requiring PCB redesign.

Availability

SMAJ54CAHM3_A/H is available at Aetrix Electronics and suitable for automotive power rail protection, industrial sensor interface hardening, and telecom DC feed safeguarding requiring stable component supply across multi-year production cycles.

Supply support for SMAJ54CAHM3_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 optimization.

The SMAJ series targets high-reliability transient suppression in space-constrained surface-mount designs, especially where automotive qualification, low leakage, and repeatable clamping are mandatory.

FAQ

What is the clamping voltage of SMAJ54CAHM3_A/H at its rated peak pulse current?

The SMAJ54CAHM3_A/H has a maximum clamping voltage (V_C) of 87.1 V at 4.6 A peak pulse current (I_PPM) under the standard 10/1000 μs waveform. This value defines the upper voltage limit imposed on protected circuitry during surge events and is measured per IEC 61000-4-5 test conditions. The SMAJ54CAHM3_A/H maintains this clamping performance across its full operating temperature range.

Is SMAJ54CAHM3_A/H qualified for automotive applications?

Yes, SMAJ54CAHM3_A/H is AEC-Q101 qualified, as confirmed by Vishay's ordering code suffix "HM3" and documentation in the 88390 datasheet. This qualification covers stress tests including temperature cycling, high-temperature reverse bias (HTRB), and ESD, making SMAJ54CAHM3_A/H suitable for engine control units, body electronics, and other automotive subsystems requiring validated reliability.

How does the bidirectional design of SMAJ54CAHM3_A/H affect PCB layout?

The SMAJ54CAHM3_A/H has no polarity marking and identical electrical behavior in both directions, allowing unrestricted orientation during placement. This eliminates the need for silkscreen polarity indicators or orientation-dependent routing, simplifying layout and reducing assembly errors. Engineers can place SMAJ54CAHM3_A/H across any two nodes requiring symmetrical overvoltage protection-such as AC-coupled signal lines or floating DC rails-without concern for anode/cathode alignment.

What is the thermal resistance of SMAJ54CAHM3_A/H, and how does it impact power dissipation?

SMAJ54CAHM3_A/H has a typical junction-to-ambient thermal resistance (R_θJA) of 120 °C/W and junction-to-lead resistance (R_θJL) of 30 °C/W. These values determine steady-state temperature rise under continuous power: at its rated 3.3 W power dissipation (P_D), junction temperature rises ~396 °C above ambient-so SMAJ54CAHM3_A/H is intended only for transient (not continuous) power handling. Layout with 0.2" × 0.2" copper pads per terminal is required to achieve the published R_θJA.

Does SMAJ54CAHM3_A/H meet RoHS and halogen-free requirements?

Yes, SMAJ54CAHM3_A/H carries the HM3 suffix, indicating it is both RoHS-compliant and halogen-free per JEDEC J-STD-201 Class 2 whisker resistance standards. This meets stringent environmental mandates for automotive and industrial end equipment, including EU ELV and China RoHS II. The molding compound is UL 94 V-0 rated, and terminals are matte tin-plated per J-STD-002 solderability requirements.