IRF543 MOSFET — Specifications & Equivalents
Manufacturer: Commonly produced by International Rectifier (now Infineon)
About the IRF543
The IRF543 is an N-channel MOSFET with a drain–source voltage (VDS) rating of 80 V, a continuous drain current (ID) of 25 A and an on-resistance (RDS(on)) of 0.1 Ω. It can dissipate up to 125 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 (VDS): 80 V
- Max continuous drain current (ID): 25 A
- On-resistance (RDS(on)): 0.1 Ω
- Power dissipation (PD): 125 W
- Max junction temperature (TJ): 150 °C
- Package: TO220
- Manufacturer: Commonly produced by International Rectifier (now Infineon)
Typical applications
With its 80 V drain–source rating the IRF543 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.
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 a rise time of 60 ns and an output capacitance (Coss) of 800 pF, which together with the gate drive determines switching loss and the practical upper frequency limit.
Choosing a replacement for the IRF543
A drop-in substitute for the IRF543 must be the same N-channel type and offer a drain–source rating of at least 80 V, a continuous drain current rating of at least 25 A and an on-resistance no higher than 0.1 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 IRF543?
The IRF543 is an N-channel MOSFET (metal-oxide-semiconductor field-effect transistor). It is rated for 80 V drain-source and 25 A continuous drain current.
What is the maximum voltage of the IRF543?
The IRF543 has a maximum drain-source voltage (Vds) of 80 V. Treat this as an absolute maximum and design with margin, especially when switching inductive loads.
How much current can the IRF543 handle?
It is rated for 25 A of continuous drain current, with power dissipation limited to 125 W. Real-world capability depends on your heatsinking and ambient temperature.
What is the on-resistance of the IRF543?
On-resistance (Rds(on)) is 0.1 Ω. Multiply by the square of your load current to estimate conduction loss.
What package does the IRF543 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 IRF543?
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.
Key Specifications
| Type | MOSFET |
|---|---|
| Channel Type | N -Channel |
| Drain-Source Voltage (Vds) | 80 V |
| Gate-Source Voltage (Vgs) | 20 V |
| Drain Current (Id) | 25 A |
| Drain-Source On-Resistance (Rds) | 0.1 |
| Rise Time (tr) | 60 |
| Output Capacitance (Coss) | 800 |
| Junction Temperature (Tj) | 150 °C |
| Package | TO220 |
| Power Dissipation (Pd) | 125 W |
Equivalent & Replacement Parts
No verified equivalents are listed for IRF543 yet.