Vishay General Semiconductor - Diodes Division SMAJ6.5AHM3_A/H

Overview

SMAJ6.5AHM3_A/H 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 6.5 V stand-off voltage (VWM), 7.22–7.98 V breakdown voltage (VBR) at 10 mA, 400 W peak pulse power (10/1000 μs), 35.7 A peak pulse current (IPPM), and clamps to ≤11.2 V at rated surge.

For engineers reviewing the SMAJ6.5AHM3_A/H datasheet, SMAJ6.5AHM3_A/H pinout, SMAJ6.5AHM3_A/H application, or SMAJ6.5AHM3_A/H equivalent, key selection criteria include clamping voltage under 11.2 V at 35.7 A, unidirectional polarity with cathode band marking, AEC-Q101 qualification status, halogen-free RoHS compliance (HM3 suffix), and compatibility with automated SMT placement on 0.2" × 0.2" copper pads.

Technical Context

This TVS diode operates as a clamping device in parallel with protected circuitry, entering avalanche conduction when reverse voltage exceeds its breakdown threshold. Its low incremental surge resistance and fast response time (<1 ns) enable effective suppression of transient energy before downstream components are stressed.

The SMAJ6.5AHM3_A/H is rated for 150 °C maximum junction temperature, exhibits a +0.061 %/°C temperature coefficient of VBR, and delivers 400 W peak pulse power only up to 78 V - above that, derated to 300 W per specification note (1).

Key Specifications

Pinout & Package

Package: SMA (DO-214AC), molded plastic case with matte tin-plated leads; polarity indicated by cathode band on unidirectional devices; meets UL 94 V-0 flammability rating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ6.5AHM3_A/H, the HE3 variant trades halogen-free compliance for lower cost in non-regulated environments, while the -M3/61 offers identical specs in a different tape-and-reel format-neither is pin-compatible in the sense of mechanical interchangeability beyond shared DO-214AC footprint.

Availability

SMAJ6.5AHM3_A/H is available at Aetrix Electronics and suitable for automotive ECUs, industrial sensor nodes, consumer USB power management, and telecom data line protection requiring stable component supply across multi-year production cycles.

Supply support for SMAJ6.5AHM3_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, automotive qualification, and high-volume manufacturability.

The SMAJ series is engineered specifically for board-level transient suppression in harsh environments, targeting applications where fast clamping, high surge robustness, and AEC-Q101 validation are mandatory.

FAQ

What is the clamping voltage of the SMAJ6.5AHM3_A/H under full-rated surge conditions?

The SMAJ6.5AHM3_A/H clamps to a maximum of 11.2 V when subjected to its rated 35.7 A peak pulse current (IPPM) using the standard 10/1000 μs waveform. This value is measured at T_A = 25 °C on 0.2" × 0.2" copper pads and defines the upper voltage limit imposed on protected circuitry during transient events. The SMAJ6.5AHM3_A/H maintains this clamping performance across its qualified operating temperature range.

Is the SMAJ6.5AHM3_A/H suitable for automotive applications?

Yes, the SMAJ6.5AHM3_A/H is AEC-Q101 qualified (as indicated by the HM3 suffix), making it suitable for automotive applications including body electronics, infotainment power rails, and sensor interface protection. Its 150 °C maximum junction temperature, halogen-free construction, and MSL Level 1 reflow compatibility meet stringent automotive manufacturing and reliability requirements. The SMAJ6.5AHM3_A/H is explicitly listed in Vishay's AEC-Q101 qualified devices table.

What does the "HM3" suffix signify in SMAJ6.5AHM3_A/H?

The "HM3" suffix in SMAJ6.5AHM3_A/H denotes halogen-free, RoHS-compliant construction with AEC-Q101 qualification. It distinguishes this variant from E3 (RoHS only) and HE3 (RoHS + AEC-Q101, but not halogen-free). The HM3 grade satisfies environmental mandates such as the EU Automotive ELV Directive and supports green supply chain initiatives. The SMAJ6.5AHM3_A/H is fully traceable to Vishay's certified halogen-free material specifications.

How does the SMAJ6.5AHM3_A/H compare to bidirectional TVS diodes like SMAJ6.5CA?

The SMAJ6.5AHM3_A/H is unidirectional and intended for DC-biased lines where polarity is fixed (e.g., VBUS, 12 V supply), offering lower leakage and higher surge capability in one direction. In contrast, SMAJ6.5CA is bidirectional and suited for AC or floating signal lines (e.g., RS-485, audio). The SMAJ6.5AHM3_A/H has a cathode band marking; SMAJ6.5CA has no polarity marking. Their breakdown and clamping voltages differ slightly due to structural asymmetry.

What is the thermal resistance of the SMAJ6.5AHM3_A/H, and how does it affect power dissipation?

The SMAJ6.5AHM3_A/H has a typical junction-to-ambient thermal resistance (R_θJA) of 120 °C/W and junction-to-lead (R_θJL) of 30 °C/W. At 25 °C ambient, its steady-state power dissipation (P_D) is rated at 3.3 W; however, this derates linearly above 25 °C. For example, at 85 °C ambient, usable P_D drops to ~1.9 W. The SMAJ6.5AHM3_A/H relies on PCB copper area for heat spreading - performance assumes minimum recommended pad layout per datasheet figure.