Vishay General Semiconductor - Diodes Division SMAJ48AHM3_A/H

Overview

SMAJ48AHM3_A/H from Vishay General Semiconductor is a unidirectional transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, designed for robust overvoltage protection of DC power rails and signal lines. It features a 48 V stand-off voltage (V_WM), 53.3–58.9 V breakdown voltage (V_BR) at 1 mA, 77.4 V maximum clamping voltage (V_C) at 5.2 A peak pulse current, and 400 W peak pulse power rating with 10/1000 μs waveform - deployed in automotive ECUs, industrial sensor interfaces, and 48 V telecom power supplies.

For engineers reviewing the SMAJ48AHM3_A/H datasheet, SMAJ48AHM3_A/H pinout, SMAJ48AHM3_A/H application, or SMAJ48AHM3_A/H equivalent, this part delivers AEC-Q101 qualified surge immunity, halogen-free RoHS compliance, and verified clamping performance under repetitive transients - critical when selecting TVS devices for ISO 7637-2/IEC 61000-4-5 compliant designs.

Technical Context

This unidirectional TVS diode operates as a voltage-clamped shunt protector: it remains high-impedance below 48 V (V_WM) and rapidly avalanches above ~53.3 V to limit transient energy. Its glass-passivated junction ensures stable breakdown and low leakage (<1 μA at V_WM), while the SMA package supports automated SMT placement and meets MSL Level 1 (260 °C reflow).

It sustains 40 A non-repetitive forward surge current (I_FSM, 8.3 ms half-sine) and exhibits 0.103 %/°C temperature coefficient of V_BR, enabling predictable clamping across -55 °C to +150 °C operating range. Thermal resistance is 120 °C/W (junction-to-ambient) on standard 0.2" × 0.2" copper pads.

Key Specifications

Pinout & Package

Package: SMA (DO-214AC), molded plastic case with matte tin-plated leads, UL 94 V-0 rated, MSL Level 1 compliant. Cathode identified by black band on body; anode is unmarked end.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ48AHM3_A/H, SMAJ48AHE3_A/H offers identical protection performance without automotive qualification or halogen-free materials, while SMBJ48A-M3/5A provides higher surge capacity in a physically larger package - enabling trade-offs between board space, certification needs, and transient energy handling.

Availability

SMAJ48AHM3_A/H is available at Aetrix Electronics and suitable for automotive electronics, industrial sensor interfaces, and 48 V telecom power supplies requiring stable component supply, long-term lifecycle support, and AEC-Q101 assurance.

Supply support for SMAJ48AHM3_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 validation.

The SMAJ series is engineered for high-reliability transient suppression in harsh environments - targeting automotive, industrial, and telecom applications where precise clamping, thermal stability, and qualification compliance are mandatory.

FAQ

What is the clamping voltage of SMAJ48AHM3_A/H at its rated peak pulse current?

The SMAJ48AHM3_A/H has a maximum clamping voltage (V_C) of 77.4 V at 5.2 A peak pulse current (I_PPM) under the standard 10/1000 μs waveform. This value is measured per JEDEC standards and guarantees that protected circuits will not experience voltages exceeding 77.4 V during a 400 W transient event - a key parameter for validating downstream IC survivability in 48 V systems.

Is SMAJ48AHM3_A/H qualified for automotive applications?

Yes, SMAJ48AHM3_A/H is AEC-Q101 qualified, as confirmed by Vishay's ordering code suffix "HM3" (halogen-free, RoHS-compliant, AEC-Q101). This qualification covers stress tests including high-temperature operating life, temperature cycling, and ESD - making SMAJ48AHM3_A/H suitable for under-hood and chassis-mounted automotive modules such as body control units and ADAS power supplies.

What does the "HM3" suffix in SMAJ48AHM3_A/H indicate?

The "HM3" suffix in SMAJ48AHM3_A/H denotes halogen-free, RoHS-compliant construction with AEC-Q101 qualification. It distinguishes this variant from commercial-grade versions (e.g., "E3") and confirms compliance with automotive material requirements, including JESD201 Class 2 whisker resistance and UL 94 V-0 flammability rating - essential for safety-critical vehicle subsystems.

How does SMAJ48AHM3_A/H compare to bidirectional TVS diodes like SMAJ48CA?

SMAJ48AHM3_A/H is unidirectional and intended for DC line protection with polarity-sensitive placement (cathode to line), whereas SMAJ48CA is bidirectional and symmetrical for AC or floating signal lines. SMAJ48AHM3_A/H offers tighter leakage (<1 μA at 48 V) and slightly lower V_C than its bidirectional counterpart, but cannot protect AC waveforms - selection depends strictly on circuit topology and signal polarity.

What is the thermal resistance of SMAJ48AHM3_A/H, and how does it affect layout?

SMAJ48AHM3_A/H has a typical junction-to-ambient thermal resistance (R_θJA) of 120 °C/W when mounted on 0.2" × 0.2" copper pads per terminal. To maintain safe operation at full 400 W surge duty, designers must ensure adequate copper area and avoid excessive trace length - especially critical in automotive applications where ambient temperatures exceed 105 °C and sustained power dissipation must stay below 3.3 W.