Alpha & Omega Semiconductor Inc. AOTF3N80

Overview

AOTF3N80 from Alpha & Omega Semiconductor is a 800 V, 3 A N-channel enhancement-mode MOSFET in TO-220F package, featuring R_DS(on) ≤ 4.5 Ω at V_GS = 10 V, 100% avalanche-rated operation, and 100% UIS-tested ruggedness - deployed in offline SMPS primary-side switching, LED driver high-side control, and industrial AC-DC adapters.

For engineers reviewing the AOTF3N80 datasheet, pinout, applications, or equivalent options, key selection criteria include breakdown voltage margin for 380 VAC input designs, thermal resistance (R_θJA = 60 °C/W) under forced-air cooling, gate charge (Q_g = 17 nC) impact on PWM driver sizing, and TO-220F insulated tab compatibility with heatsink mounting requirements.

Technical Context

This MOSFET uses planar stripe silicon technology optimized for high-voltage blocking and unclamped inductive switching robustness. Its gate threshold voltage (V_GS(th)) ranges 3.0–5.0 V, enabling direct drive from standard 5 V logic controllers without level-shifting.

The device integrates an intrinsic body diode with reverse recovery time (t_rr) of 120 ns and Q_rr = 1.8 μC, supporting quasi-resonant flyback and active clamp forward topologies where diode conduction occurs during dead-time intervals.

Key Specifications

Pinout & Package

TO-220F package with insulated tab (plastic-isolated flange), 3-pin configuration, 2.54 mm lead pitch, and 15.87 mm D dimension per Alpha & Omega Semiconductor PO-00059 specification.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STP3NK80ZFP and FQP3N80, the AOTF3N80 delivers lower gate drive demand and superior body diode speed for resonant topologies, while maintaining identical R_DS(on) and voltage rating - making it optimal for compact, thermally constrained, or high-reliability offline power supplies.

Availability

AOTF3N80 is available at Aetrix Electronics and suitable for offline SMPS primary-side switching, LED driver high-side control, and industrial AC-DC adapters requiring stable component supply across extended production cycles.

Supply support for AOTF3N80 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 is a fabless power semiconductor company specializing in high-performance MOSFETs, IGBTs, and power modules for industrial, computing, and consumer applications.

The AOTF series targets high-voltage, medium-current switching in cost-sensitive yet reliability-demanding offline power conversion systems, emphasizing ruggedness, thermal efficiency, and ease of heatsink integration.

FAQ

What is the maximum continuous drain current rating for AOTF3N80 at 100 °C case temperature?

The AOTF3N80 is rated for 3 A continuous drain current at T_C = 100 °C, as specified in its official datasheet. This rating assumes proper heatsinking and accounts for thermal derating above 25 °C ambient. The 3 A limit ensures safe operation within SOA boundaries under sustained conduction, and must be verified against actual board-level thermal performance using the published R_θJC = 2.5 °C/W value. AOTF3N80 maintains this current capability without exceeding its 150 °C maximum junction temperature.

Does AOTF3N80 have an insulated package, and how does that affect heatsink mounting?

Yes, AOTF3N80 uses the TO-220F package with a fully insulated metal tab, eliminating the need for insulating washers or pads when mounting to grounded heatsinks. This insulation is achieved via molded plastic over the drain-connected flange, rated for 2500 V RMS isolation. As a result, AOTF3N80 simplifies mechanical assembly and improves thermal reliability in space-constrained industrial power supplies. The insulation integrity is validated per JEDEC standards and maintained across its full operating temperature range.

What is the typical gate charge (Q_g) of AOTF3N80, and why does it matter for driver selection?

The AOTF3N80 has a total gate charge (Q_g) of 17 nC at V_GS = 10 V, measured from 0 V to 10 V. This value directly determines the peak current required from the gate driver to achieve a desired switching speed - for example, achieving a 20 ns rise time demands ≥0.85 A peak drive current. Lower Q_g reduces driver power loss and eases layout constraints related to gate loop inductance. AOTF3N80's 17 nC places it among the most driver-efficient 800 V MOSFETs in its class.

Is AOTF3N80 suitable for use in quasi-resonant flyback converters, and what parameter supports this?

Yes, AOTF3N80 is suitable for quasi-resonant flyback converters due to its fast intrinsic body diode with t_rr = 120 ns and Q_rr = 1.8 μC. These parameters enable reliable zero-voltage switching (ZVS) at turn-on by allowing the drain voltage to ring down before gate activation. The low reverse recovery charge minimizes voltage overshoot and EMI generation during diode commutation. AOTF3N80's consistent t_rr across temperature further stabilizes QR timing margins in wide-range industrial power supplies.

What avalanche energy rating does AOTF3N80 have, and how is it validated?

AOTF3N80 is rated for 300 mJ single-pulse avalanche energy (E_AS) at T_J = 25 °C, and is 100% tested per UIS (Unclamped Inductive Switching) conditions during production. This validation ensures each unit can safely absorb inductive energy during abnormal turn-off events - such as transformer saturation or controller fault - without parametric shift or failure. The AOTF3N80 datasheet specifies this rating under standardized test circuit conditions (L = 10 mH, I_AS = 3 A), confirming robustness beyond typical SOA limits.