IRFZ45 MOSFET — Specifications & Equivalents

About the IRFZ45

The IRFZ45 is an N-channel MOSFET with a drain–source voltage (V_DS) rating of 60 V, a continuous drain current (I_D) of 50 A and an on-resistance (R_DS(on)) of 0.035 Ω. It can dissipate up to 150 W and is rated to a junction temperature of 150 °C. It is supplied in the TO220 package.

At a glance

• Type: N-channel MOSFET
• Max drain–source voltage (V_DS): 60 V
• Max continuous drain current (I_D): 50 A
• On-resistance (R_DS(on)): 0.035 Ω
• Power dissipation (P_D): 150 W
• Max junction temperature (T_J): 150 °C
• Package: TO220
• Manufacturer: Commonly produced by International Rectifier (now Infineon)

Typical applications

With its 60 V drain–source rating the IRFZ45 sits in the mid-range class of switching MOSFETs, typically found in 24 V and 48 V industrial and battery systems, motor drives and H-bridges and load and hot-swap switching.

The 50 A current rating puts it in high-current territory, where conduction loss (I² × R_DS(on)) and thermal design usually matter more than switching loss. Budget for adequate copper area and a heatsink.

The low 0.035 Ω on-resistance keeps conduction loss down, which suits synchronous rectification and continuous high-current paths.

Choosing a replacement for the IRFZ45

A drop-in substitute for the IRFZ45 must be the same N-channel type and offer a drain–source rating of at least 60 V, a continuous drain current rating of at least 50 A and an on-resistance no higher than 0.035 Ω if efficiency and heat matter.

Mechanically, check the replacement against the TO220 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 IRFZ45?

The IRFZ45 is an N-channel MOSFET (metal-oxide-semiconductor field-effect transistor). It is rated for 60 V drain-source and 50 A continuous drain current.

What is the maximum voltage of the IRFZ45?

The IRFZ45 has a maximum drain-source voltage (Vds) of 60 V. Treat this as an absolute maximum and design with margin, especially when switching inductive loads.

How much current can the IRFZ45 handle?

It is rated for 50 A of continuous drain current, with power dissipation limited to 150 W. Real-world capability depends on your heatsinking and ambient temperature.

What is the on-resistance of the IRFZ45?

On-resistance (Rds(on)) is 0.035 Ω. Multiply by the square of your load current to estimate conduction loss.

What package does the IRFZ45 come in?

It is listed in TO220. Verify the pinout of the specific variant, as one outline can carry different pin assignments.

What can I use to replace the IRFZ45?

No verified equivalents are listed yet. Choose a part of the same polarity that meets or exceeds every rating above and shares a compatible package and pinout.