Alpha & Omega Semiconductor Inc. AON6444

Overview

AON6444 from Alpha & Omega Semiconductor is a 30 V, 58 A, 4.2 mΩ (typ.) N-channel MOSFET in a 5x6 mm DFN package, optimized for high-efficiency synchronous buck converters and load switches in DC-DC power stages.

For engineers reviewing the AON6444 datasheet, pinout, applications, or equivalent options, key selection criteria include R_DS(on) at 10 V and 4.5 V gate drive, Q_g of 17 nC, SOA rating at T_C = 25 °C, and compliance with AOS Green (halogen-free) packaging standards.

Technical Context

The AON6444 employs trench-gate MOSFET technology to achieve low conduction loss and fast switching performance. It supports gate drive voltages from 4.5 V to 20 V and features a maximum V_GS rating of ±20 V.

Thermal resistance R_θJC is 1.9 °C/W, enabling high-current operation with minimal junction temperature rise under forced-air cooling. The device is rated for continuous drain current I_D = 58 A at T_C = 25 °C and 39 A at T_C = 100 °C.

Key Specifications

Pinout & Package

Package: 5×6 mm DFN-8 (exposed drain pad), RoHS-compliant and halogen-free per AOS Green Policy (no "L" suffix required - AON6444 is green by default).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar N-channel power MOSFET applications.

Compared with IRF6642 and SiR626DP, the AON6444 delivers superior thermal resistance (1.9 °C/W vs. ≥3.5 °C/W) and tighter gate threshold distribution (1.2–2.2 V), making it preferred for compact, high-reliability DC-DC stages requiring consistent turn-on behavior across temperature.

Availability

AON6444 is available at Aetrix Electronics and suitable for server VRMs, industrial PLC I/O modules, and telecom power supplies requiring stable component supply and halogen-free compliance.

Supply support for AON6444 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

Alpha & Omega Semiconductor (AOS) is a fabless power semiconductor company specializing in high-performance MOSFETs, IGBTs, and power modules for computing, industrial, and automotive markets.

The AON6444 belongs to AOS's NextPower™ SF series, engineered for high-frequency, high-current DC-DC conversion with emphasis on low R_DS(on), fast switching, and robust thermal performance.

FAQ

What is the maximum continuous drain current rating for AON6444 at 100 °C case temperature?

The AON6444 is rated for 39 A continuous drain current at T_C = 100 °C, based on its R_DS(on) temperature coefficient and thermal resistance of 1.9 °C/W. This rating assumes proper PCB copper area and minimal ambient airflow. Derating is required above 100 °C case temperature, and the absolute maximum pulsed current remains 200 A per datasheet SOA limits. The AON6444 maintains safe operation under these conditions when mounted on 2 oz copper with ≥4 cm² exposed drain pad area.

Does AON6444 require a gate resistor for typical 500 kHz buck converter operation?

The AON6444 has a total gate charge of 17 nC and gate resistance of ~1.2 Ω, making it compatible with standard 2 A peak gate drivers without mandatory external gate resistors. However, a 2–5 Ω series resistor is recommended to damp ringing and control di/dt during turn-on/turn-off, especially in high-current (>30 A) or high-dV/dt layouts. The AON6444's low Q_gd (5.2 nC) further reduces sensitivity to gate resistance variation.

Is AON6444 compliant with halogen-free and RoHS requirements?

Yes, the AON6444 is fully compliant with both RoHS Directive 2011/65/EU and halogen-free standards per IEC 61249-2-21, containing <900 ppm bromine and chlorine individually and <1500 ppm total halogens. As confirmed by AOS Green Policy documentation, all AON6444 units manufactured after 2010 are halogen-free by default - no "L" suffix is used, and no non-green variants exist for this DFN-8 part number.

Can AON6444 be used in high-side switching configurations?

The AON6444 is an N-channel MOSFET and requires gate drive voltage exceeding the source potential for high-side operation - typically implemented using a bootstrap or isolated gate driver. Its 20 V maximum V_GS rating and 1.2–2.2 V gate threshold support reliable high-side use when paired with appropriate level-shifting circuitry. The AON6444's low Q_gd and fast t_f (15 ns) also minimize shoot-through risk in half-bridge topologies.

What is the recommended PCB layout practice for the exposed drain pad of AON6444?

The exposed drain pad of the AON6444 must be soldered to a minimum 12 mm × 12 mm thermal pad on the primary layer, connected via ≥6 thermal vias (0.3 mm diameter) to inner and bottom-layer ground planes. Avoid solder mask over the pad. This layout achieves the specified R_θJC = 1.9 °C/W and prevents localized overheating. The AON6444's performance and reliability depend critically on this thermal interface - insufficient copper area increases junction temperature by >20 °C at 40 A.