Vishay General Semiconductor - Diodes Division SMAJ15AHM3_A/H

Overview

SMAJ15AHM3_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 15 V stand-off voltage (VWM), 16.7–18.5 V breakdown voltage (VBR) at 1 mA, 24.4 V maximum clamping voltage (VC) at 16.4 A peak pulse current (IPPM), and 400 W peak pulse power (10/1000 μs waveform), commonly deployed to protect MOSFETs and ICs in automotive power supplies.

For engineers reviewing the SMAJ15AHM3_A/H datasheet, SMAJ15AHM3_A/H pinout, SMAJ15AHM3_A/H application, or SMAJ15AHM3_A/H equivalent, key selection criteria include clamping voltage margin relative to protected device VDS/VDD ratings, thermal resistance (RθJA = 120 °C/W), AEC-Q101 qualification status, unidirectional polarity marking, and compatibility with automated SMT placement on 0.2" × 0.2" copper pads.

Technical Context

This TVS diode operates as a shunt-type overvoltage protection device, conducting when reverse voltage exceeds its breakdown threshold to divert surge energy away from downstream components. Its glass-passivated junction ensures stable leakage (<1.0 μA at VWM) and fast response time (<1.0 ps), while the SMA package supports high-density PCB layouts and meets MSL level 1 reflow requirements (peak 260 °C).

The device is rated for non-repetitive 8.3 ms half-sine surge currents up to 40 A (IFSM), with derated peak pulse power above 78 V (300 W). Its temperature coefficient of VBR is +0.088 %/°C, enabling predictable voltage drift across the -55 °C to +150 °C operating junction range.

Key Specifications

Pinout & Package

Package: SMA (DO-214AC), surface-mount, halogen-free, RoHS-compliant, MSL Level 1, matte tin-plated leads solderable per J-STD-002.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ15AHM3_A/H, SMAJ15AHE3_A/H omits halogen-free certification and uses conventional plating, while SMAJ15A-QH retains identical performance but changes reel packaging format-both require no schematic or layout revision but differ in compliance scope and supply chain configuration.

Availability

SMAJ15AHM3_A/H is available at Aetrix Electronics and suitable for automotive power rail protection, industrial sensor interface hardening, and telecom DC input surge suppression requiring stable component supply, halogen-free compliance, and AEC-Q101 qualification.

Supply support for SMAJ15AHM3_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 automotive-grade validation.

The SMAJ series is engineered specifically for robust transient suppression in harsh environments-targeting automotive, industrial, and telecom systems where repeatable clamping performance and long-term stability under thermal stress are critical.

FAQ

What is the clamping voltage of SMAJ15AHM3_A/H at its rated peak pulse current?

The SMAJ15AHM3_A/H has a maximum clamping voltage (VC) of 24.4 V at its rated peak pulse current (IPPM) of 16.4 A, measured using the standard 10/1000 μs double-exponential waveform. This value defines the upper voltage limit imposed on protected circuitry during a surge event and is confirmed in the Vishay datasheet Document Number 88390, page 2. The SMAJ15AHM3_A/H maintains this clamping performance across its full operating temperature range.

Is SMAJ15AHM3_A/H qualified for automotive applications?

Yes, SMAJ15AHM3_A/H is AEC-Q101 qualified, as indicated by the "HM3" suffix and confirmed in the Vishay ordering information table (page 3 of Document Number 88390). This qualification covers stress tests including temperature cycling, high-temperature operating life, and unbiased highly accelerated stress testing. The SMAJ15AHM3_A/H is approved for use in engine control units, body electronics, and ADAS power domains where automotive-grade reliability is mandatory.

What does the "HM3" suffix signify in SMAJ15AHM3_A/H?

The "HM3" suffix in SMAJ15AHM3_A/H denotes halogen-free, RoHS-compliant construction with matte tin-plated leads meeting J-STD-002 solderability standards, plus AEC-Q101 qualification. Per Vishay's ordering guide (Document Number 88390, page 3), "HM3" distinguishes it from "HE3" (RoHS-compliant, AEC-Q101, but not halogen-free) and "E3/M3" (commercial grade only). The "_A/H" indicates revision A in 7-inch tape-and-reel packaging (H-code).

How does SMAJ15AHM3_A/H compare to SMAJ15A in terms of thermal performance?

SMAJ15AHM3_A/H shares identical thermal characteristics with the base SMAJ15A: typical junction-to-ambient thermal resistance (RθJA) is 120 °C/W on 0.2" × 0.2" copper pads, and junction-to-lead (RθJL) is 30 °C/W. These values are unaffected by the HM3 qualification or halogen-free materials. The SMAJ15AHM3_A/H therefore exhibits the same steady-state self-heating behavior and surge derating curves as documented in Figure 2 of the Vishay datasheet (Document Number 88390).

Can SMAJ15AHM3_A/H be used in bidirectional configurations?

No, SMAJ15AHM3_A/H is a unidirectional TVS diode, as confirmed by its part number ending in "A" (not "CA") and explicit designation in the Vishay datasheet Table on page 2. It conducts only in reverse bias and requires correct cathode orientation toward the protected line. For bidirectional protection, engineers must select an SMAJ15CA variant-SMAJ15AHM3_A/H lacks symmetrical breakdown and will not suppress positive-going transients on grounded lines.