IRF3805S MOSFET — Specifications & Equivalents
Manufacturer: Commonly produced by International Rectifier (now Infineon)
About the IRF3805S
The IRF3805S is an N-channel MOSFET with a drain–source voltage (VDS) rating of 55 V, a continuous drain current (ID) of 210 A and an on-resistance (RDS(on)) of 0.0033 Ω. It can dissipate up to 300 W and is rated to a junction temperature of 175 °C. It is supplied in the TO263 package.
At a glance
- Type: N-channel MOSFET
- Max drain–source voltage (VDS): 55 V
- Max continuous drain current (ID): 210 A
- On-resistance (RDS(on)): 0.0033 Ω
- Power dissipation (PD): 300 W
- Max junction temperature (TJ): 175 °C
- Package: TO263
- Manufacturer: Commonly produced by International Rectifier (now Infineon)
Typical applications
With its 55 V drain–source rating the IRF3805S sits in the low-voltage class of switching MOSFETs, typically found in 12 V and 24 V automotive and industrial rails, synchronous buck converters, load switching and reverse-polarity protection and H-bridges for small motors.
The 210 A current rating puts it in high-current territory, where conduction loss (I² × RDS(on)) and thermal design usually matter more than switching loss. Budget for adequate copper area and a heatsink.
The low 0.0033 Ω on-resistance keeps conduction loss down, which suits synchronous rectification and continuous high-current paths.
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 20 ns and an output capacitance (Coss) of 1260 pF, which together with the gate drive determines switching loss and the practical upper frequency limit.
Choosing a replacement for the IRF3805S
A drop-in substitute for the IRF3805S must be the same N-channel type and offer a drain–source rating of at least 55 V, a continuous drain current rating of at least 210 A and an on-resistance no higher than 0.0033 Ω if efficiency and heat matter.
Mechanically, check the replacement against the TO263 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 IRF3805S?
The IRF3805S is an N-channel MOSFET (metal-oxide-semiconductor field-effect transistor). It is rated for 55 V drain-source and 210 A continuous drain current.
What is the maximum voltage of the IRF3805S?
The IRF3805S has a maximum drain-source voltage (Vds) of 55 V. Treat this as an absolute maximum and design with margin, especially when switching inductive loads.
How much current can the IRF3805S handle?
It is rated for 210 A of continuous drain current, with power dissipation limited to 300 W. Real-world capability depends on your heatsinking and ambient temperature.
What is the on-resistance of the IRF3805S?
On-resistance (Rds(on)) is 0.0033 Ω. Multiply by the square of your load current to estimate conduction loss.
What package does the IRF3805S come in?
It is listed in TO263. Verify the pinout of the specific variant, as one outline can carry different pin assignments.
What can I use to replace the IRF3805S?
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) | 55 V |
| Gate-Source Voltage (Vgs) | 20 V |
| Drain Current (Id) | 210 A |
| Drain-Source On-Resistance (Rds) | 0.0033 |
| Rise Time (tr) | 20 nS |
| Output Capacitance (Coss) | 1260 pF |
| Junction Temperature (Tj) | 175 °C |
| Package | TO263 |
| Power Dissipation (Pd) | 300 W |
Equivalent & Replacement Parts
No verified equivalents are listed for IRF3805S yet.