IRFY9240 MOSFET — Specifications & Equivalents

About the IRFY9240

The IRFY9240 is a MOSFET with a drain–source voltage (V_DS) rating of 200 V and a continuous drain current (I_D) of 9.4 A. It can dissipate up to 100 W and is rated to a junction temperature of 150 °C. It is supplied in the TO257AA package.

At a glance

• Type: MOSFET
• Max drain–source voltage (V_DS): 200 V
• Max continuous drain current (I_D): 9.4 A
• Power dissipation (P_D): 100 W
• Max junction temperature (T_J): 150 °C
• Package: TO257AA
• Manufacturer: Commonly produced by International Rectifier (now Infineon)

Typical applications

With its 200 V drain–source rating the IRFY9240 sits in the medium-high-voltage class of switching MOSFETs, typically found in telecom and industrial DC rails, boost and flyback converters, LED and backlight drivers and power-factor-correction stages. Common where the bus sits well above 100 V but below rectified mains.

Gate drive and switching notes

Keep gate–source voltage within the ±20 V maximum; exceeding it punctures the gate oxide and destroys the device permanently.

Switching behaviour is characterised by an output capacitance (C_oss) of 570 pF, which together with the gate drive determines switching loss and the practical upper frequency limit.

Choosing a replacement for the IRFY9240

A drop-in substitute for the IRFY9240 should match its polarity and offer a drain–source rating of at least 200 V and a continuous drain current rating of at least 9.4 A.

Mechanically, check the replacement against the TO257AA footprint and confirm the pin order — parts sharing a package outline do not always share a pinout.

Where the application switches inductive loads or runs near the voltage limit, keep extra headroom rather than choosing a part that only just meets the original numbers.

Frequently asked questions

What is the IRFY9240?

The IRFY9240 is a MOSFET (metal-oxide-semiconductor field-effect transistor). It is rated for 200 V drain-source and 9.4 A continuous drain current.

What is the maximum voltage of the IRFY9240?

The IRFY9240 has a maximum drain-source voltage (Vds) of 200 V. Treat this as an absolute maximum and design with margin, especially when switching inductive loads.

How much current can the IRFY9240 handle?

It is rated for 9.4 A of continuous drain current, with power dissipation limited to 100 W. Real-world capability depends on your heatsinking and ambient temperature.

What package does the IRFY9240 come in?

It is listed in TO257AA. Verify the pinout of the specific variant, as one outline can carry different pin assignments.

What can I use to replace the IRFY9240?

This page lists 17 candidate equivalents matched on electrical ratings and package. Any replacement should meet or exceed the original voltage, current and dissipation figures and use a compatible drive level.