Alpha & Omega Semiconductor Inc. AOTF3N100

Overview

AOTF3N100 from Alpha & Omega Semiconductor is a 100 V, 3 A N-channel enhancement-mode MOSFET in TO-220F package, featuring R_DS(on) ≤ 1.4 Ω at V_GS = 10 V, 100% avalanche-rated operation, and 150 °C maximum junction temperature - used in offline AC-DC auxiliary power supplies for gate driving and bias generation.

For engineers reviewing the AOTF3N100 datasheet, pinout, applications, or equivalent options, key selection criteria include its 100 V blocking rating, low gate charge (Q_g = 7.5 nC), enhanced thermal performance via insulated TO-220F package, and suitability for high-reliability industrial SMPS designs requiring creepage/clearance compliance.

Technical Context

This MOSFET employs planar trench-gate technology to achieve stable R_DS(on) over temperature and robust unclamped inductive switching (UIS) capability up to 100 mJ at T_J = 25 °C. Its insulated TO-220F package provides 2.54 mm creepage distance between drain tab and leads, enabling reinforced insulation in Class II systems.

The device operates with threshold voltage V_GS(th) of 2.0–4.0 V, supports standard logic-level gate drive (10 V), and exhibits typical input capacitance C_iss = 380 pF at V_DS = 25 V - optimized for flyback and buck converter primary-side switching below 100 kHz.

Key Specifications

Pinout & Package

TO-220F package with insulated metal tab (drain-connected), vertical lead frame, and 3-pin configuration. Drain tab electrically isolated from pins by molded compound; creepage ≥ 2.54 mm between tab and source/ground pins.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage MOSFET applications.

Compared with STP3NK100Z and IXTP3N100D2, the AOTF3N100 delivers superior conduction efficiency, higher UIS energy margin, and built-in isolation - making it optimal for space-constrained, safety-critical auxiliary supplies where thermal and reliability margins are tight.

Availability

AOTF3N100 is available at Aetrix Electronics and suitable for industrial AC-DC adapters, smart meter power supplies, and LED driver auxiliary rails requiring stable component supply across multi-year production cycles.

Supply support for AOTF3N100 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-efficiency MOSFETs, IGBTs, and power modules for power conversion and motor control.

The AOTF3N100 belongs to AOS's insulated high-voltage MOSFET product line, engineered specifically for safety-critical auxiliary power stages in offline converters where creepage, UIS robustness, and thermal reliability are non-negotiable.

FAQ

What is the maximum continuous drain current rating for the AOTF3N100?

The AOTF3N100 is rated for 3 A continuous drain current at case temperature T_C = 25 °C. Derating is required above this temperature per the SOA curve; at T_C = 100 °C, the usable I_D drops to approximately 1.8 A. This rating assumes proper PCB copper area and minimal thermal resistance to ambient. The AOTF3N100 must be mounted with appropriate torque on the heatsink to maintain thermal performance.

Does the AOTF3N100 have an insulated package, and what does that mean for PCB layout?

Yes, the AOTF3N100 uses a TO-220F package with an electrically insulated drain tab. This means the metal tab - though internally connected to the drain - is coated with insulating material providing ≥2.54 mm creepage to pins. As a result, no external insulating washer or silicone pad is needed between the tab and heatsink, simplifying mechanical assembly and improving long-term thermal interface reliability in the AOTF3N100.

What is the gate threshold voltage range for the AOTF3N100, and how does it affect drive circuit design?

The AOTF3N100 has a gate threshold voltage V_GS(th) range of 2.0 V to 4.0 V, measured at I_D = 250 µA. This wide range necessitates gate drive voltages ≥10 V to ensure full enhancement across process variation and temperature. Drive circuits must avoid marginal 5 V logic-level operation, as partial turn-on increases conduction loss and thermal stress. The AOTF3N100 performs reliably with standard 12 V gate drivers.

Is the AOTF3N100 suitable for use in flyback converters operating in discontinuous conduction mode (DCM)?

Yes, the AOTF3N100 is widely deployed in DCM flyback converters for auxiliary power supplies. Its 100 mJ UIS rating handles transformer leakage energy safely, and its 7.5 nC gate charge minimizes switching losses at typical 65–100 kHz frequencies. The AOTF3N100's low R_DS(on) also reduces conduction loss during the extended on-time typical of DCM operation.

How does the AOTF3N100 compare to standard TO-220 MOSFETs in terms of thermal performance?

The AOTF3N100's TO-220F package maintains thermal resistance R_θJC ≈ 3.5 °C/W - comparable to standard TO-220 - but adds electrical insulation without compromising thermal path integrity. Unlike insulated packages using thermal pads or adhesives, the AOTF3N100's molded insulation avoids thermal interface degradation over time or under thermal cycling, preserving long-term junction temperature stability in the AOTF3N100.