Vishay General Semiconductor - Diodes Division SMAJ9.0AHM3/I

Overview

SMAJ9.0AHM3/I from Vishay General Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, designed to protect sensitive electronics against voltage transients induced by inductive load switching and lightning surges. It features a 9.0 V stand-off voltage (V_WM), 10.0–11.1 V breakdown voltage (V_BR) at 1 mA, 15.4 V maximum clamping voltage (V_C) at 26.0 A peak pulse current, and 400 W peak pulse power rating with 10/1000 μs waveform.

For engineers reviewing the SMAJ9.0AHM3/I datasheet, SMAJ9.0AHM3/I pinout, SMAJ9.0AHM3/I application, or SMAJ9.0AHM3/I equivalent, this device is selected for robust overvoltage protection on DC power rails and low-voltage signal lines where fast response (<1 ns), low clamping ratio, and AEC-Q101 qualification (via HM3 suffix) are critical design requirements.

Technical Context

This TVS diode operates as a unidirectional avalanche clamp, conducting only in reverse bias above V_BR to limit transient voltages across protected circuit nodes. Its glass-passivated junction ensures stable breakdown characteristics and low leakage (≤5.0 μA at V_WM), while its MSL Level 1 moisture sensitivity rating supports lead-free reflow up to 260 °C peak.

The device delivers 400 W peak pulse power handling at T_A = 25 °C (derated linearly above 25 °C per Fig. 2), with thermal resistance of 120 °C/W (junction-to-ambient) and 30 °C/W (junction-to-lead), enabling reliable operation under repetitive surge conditions when mounted on 5.0 mm × 5.0 mm copper pads per JEDEC standard layout.

Key Specifications

Pinout & Package

Package: SMA (DO-214AC), molded plastic case with matte tin-plated leads, MSL Level 1, RoHS-compliant and halogen-free (HM3 suffix). Cathode indicated by band on body; anode is unmarked end.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ9.0AHM3/I, SMAJ9.0A-M3/5A omits halogen-free certification and automotive qualification, while SMAJ9.0AHE3_A/I retains AEC-Q101 but uses non-halogen-free molding compound-making SMAJ9.0AHM3/I the only option satisfying both halogen-free and automotive-grade requirements simultaneously.

Availability

SMAJ9.0AHM3/I is available at Aetrix Electronics and suitable for automotive electronics, industrial sensor systems, and telecom infrastructure requiring stable component supply with guaranteed halogen-free and AEC-Q101-compliant TVS protection.

Supply support for SMAJ9.0AHM3/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 high-reliability and automotive-qualified components.

The SMAJ series is engineered for robust transient suppression in harsh environments, targeting automotive power distribution, industrial control I/O, and telecom DC feeding applications where consistent clamping performance and long-term stability are mandatory.

FAQ

What is the clamping voltage of the SMAJ9.0AHM3/I under a 10/1000 μs surge?

The SMAJ9.0AHM3/I has a maximum clamping voltage (V_C) of 15.4 V at 26.0 A peak pulse current (I_PPM) with a 10/1000 μs waveform. This value is measured per IEC 61000-4-5 test conditions and defines the highest voltage imposed on protected circuitry during a standardized surge event. The SMAJ9.0AHM3/I maintains this clamping performance across its specified operating temperature range (-55 °C to +150 °C), with minimal derating up to 78 V V_WM.

Is the SMAJ9.0AHM3/I suitable for automotive applications?

Yes, the SMAJ9.0AHM3/I is AEC-Q101 qualified, as confirmed by its HM3 suffix and documentation in Vishay's 88390 datasheet. It meets automotive reliability requirements including temperature cycling, humidity testing, and mechanical shock. The SMAJ9.0AHM3/I is specifically intended for use in engine control units, body control modules, and ADAS sensor interfaces where halogen-free construction and extended temperature operation are mandated.

What does the "HM3" suffix indicate in SMAJ9.0AHM3/I?

The "HM3" suffix in SMAJ9.0AHM3/I denotes halogen-free, RoHS-compliant, and AEC-Q101-qualified construction. "H" stands for AEC-Q101 qualification, "M3" confirms halogen-free molding compound meeting IEC 61249-2-21, and the "/I" indicates packaging in 13-inch tape-and-reel format with 7500 units per reel. This distinguishes it from M3-only (RoHS/halogen-free, no AEC-Q101) and HE3 (RoHS/AEC-Q101, not halogen-free) variants.

How does the SMAJ9.0AHM3/I compare to bidirectional TVS diodes like SMAJ9.0CA?

The SMAJ9.0AHM3/I is unidirectional and intended for DC rail protection where polarity is fixed (e.g., +12 V to ground), whereas SMAJ9.0CA is bidirectional and suited for AC-coupled or floating signal lines. SMAJ9.0AHM3/I exhibits lower leakage (<5.0 μA at 9.0 V) and higher surge current capability (26.0 A vs. ~24 A for SMAJ9.0CA), but cannot suppress positive transients on grounded lines. Its cathode band marking ensures correct orientation during placement.

What is the thermal resistance of the SMAJ9.0AHM3/I, and how does it affect PCB layout?

The SMAJ9.0AHM3/I has a typical junction-to-ambient thermal resistance (R_θJA) of 120 °C/W and junction-to-lead (R_θJL) of 30 °C/W. To maintain safe operation under repetitive surges, PCB layout must use minimum 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal, as specified in the datasheet. Smaller pads increase R_θJA, risking thermal runaway during sustained transient activity-especially above 25 °C ambient.