Alpha & Omega Semiconductor Inc. AOD9N50

Overview

AOD9N50 from Alpha & Omega Semiconductor is a 500 V, 9 A N-channel enhancement-mode MOSFET in TO-252 (DPAK) package, featuring R_DS(on) ≤ 0.86 Ω at V_GS = 10 V, 100% UIS-tested avalanche robustness, and optimized for offline AC-DC power supplies operating up to 150 °C junction temperature.

For engineers reviewing the AOD9N50 datasheet, pinout, applications, or equivalent options, key selection criteria include its guaranteed unclamped inductive switching capability (E_AS = 433 mJ), low gate charge (Q_g = 19.5 nC typ), and thermal performance with R_θJC = 0.7 °C/W - critical for high-reliability flyback and PFC stages.

Technical Context

The AOD9N50 employs Alpha & Omega's proprietary high-voltage trench MOSFET process, delivering low R_DS(on) (0.71–0.86 Ω), low input/output capacitances (C_iss = 962 pF typ, C_oss = 98 pF typ), and tightly controlled gate threshold (V_GS(th) = 3.3–4.5 V). Its 600 V BVDSS rating at 150 °C ensures margin in 400 V DC bus applications.

Designed for hard-switched topologies, it supports fast switching (t_r = 44 ns, t_f = 35 ns) with low reverse recovery charge (Q_rr = 3.5 mC typ) and body diode softness (trr = 332 ns typ), reducing EMI and voltage overshoot in discontinuous conduction mode (DCM) flyback converters.

Key Specifications

Pinout & Package

Package: TO-252 (DPAK), surface-mount, exposed drain pad for thermal and electrical connection. Standard pin assignment: Pin 1 = Gate, Pin 2 = Drain (tab), Pin 3 = Source.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STP9NK50ZFP and IPP60R190C7, the AOD9N50 delivers optimal balance of surface-mount integration, proven avalanche ruggedness, and gate-drive efficiency for mid-power offline converters - avoiding both over-engineering and reliability compromises.

Availability

AOD9N50 is available at Aetrix Electronics and suitable for AC-DC flyback converters, PFC boost stages, and isolated forward power supplies requiring stable component supply, long-term lifecycle support, and traceable sourcing for industrial and consumer OEM programs.

Supply support for AOD9N50 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 ICs for power conversion and management.

The AOD9N50 belongs to AOS's high-voltage trench MOSFET product line, engineered specifically for rugged, cost-effective switching in offline AC-DC power supplies and industrial motor drives.

FAQ

What is the maximum junction temperature rating for the AOD9N50?

The AOD9N50 has a maximum junction temperature (T_J) rating of 150 °C, validated across all absolute maximum ratings and thermal characteristics. This rating is used to define its power de-rating curve (Figure 12), avalanche energy limits, and safe operating area boundaries. Operation beyond 150 °C risks permanent parametric shift or catastrophic failure. The AOD9N50 must be thermally designed to maintain T_J ≤ 150 °C under worst-case ambient and load conditions.

Does the AOD9N50 support logic-level gate drive?

The AOD9N50 is not a logic-level MOSFET; its gate threshold voltage (V_GS(th)) ranges from 3.3 V to 4.5 V, and full enhancement requires V_GS ≥ 10 V for R_DS(on) ≤ 0.86 Ω. While it may partially turn on at 5 V, conduction losses become excessive and unpredictable. For reliable operation, the AOD9N50 must be driven with a minimum 10 V gate-source voltage - compatible with standard PWM controllers such as UC3842, TL494, or dedicated gate drivers like UCC27531.

Is the AOD9N50 pin-compatible with the AOI9N50?

Yes, the AOD9N50 and AOI9N50 share identical electrical specifications and pinout, but differ only in package: AOD9N50 uses TO-252 (DPAK), while AOI9N50 uses TO-251 (IPAK). Both have Gate–Drain–Source pin order in top view and identical thermal and switching parameters. Layouts designed for AOD9N50 can accommodate AOI9N50 with minor footprint adjustment for lead pitch, but mechanical mounting differs due to TO-251's single leadform versus TO-252's gull-wing leads.

What does "100 % UIS Tested" mean for the AOD9N50?

"100 % UIS Tested" means every AOD9N50 unit undergoes individual unclamped inductive switching stress testing at production level, verifying its ability to withstand single-pulse avalanche energy up to 433 mJ at T_J = 25 °C. This ensures consistent ruggedness against inductive kickback in transformer-based topologies - unlike statistical sampling or qualification-only testing. The AOD9N50's UIS rating directly supports reliable operation in flyback and forward converters without external clamping components.

Can the AOD9N50 be used in synchronous rectification applications?

No, the AOD9N50 is not recommended for synchronous rectification. It is an N-channel high-voltage MOSFET optimized for primary-side switching, with body diode reverse recovery time (t_rr = 332 ns typ) and Q_rr (3.5 mC) unsuitable for secondary-side rectification where fast, soft recovery is mandatory. Synchronous rectifiers require low V_F, ultra-low Q_rr, and often P-channel or logic-level N-channel devices. The AOD9N50's design intent, characterization, and qualification focus exclusively on high-side/hard-switched primary roles.