IRF644A MOSFET — Specifications & Equivalents
Manufacturer: Commonly produced by International Rectifier (now Infineon)
About the IRF644A
The IRF644A is an N-channel MOSFET with a drain–source voltage (VDS) rating of 250 V, a continuous drain current (ID) of 14 A and an on-resistance (RDS(on)) of 0.28 Ω. It can dissipate up to 139 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): 250 V
- Max continuous drain current (ID): 14 A
- On-resistance (RDS(on)): 0.28 Ω
- Power dissipation (PD): 139 W
- Max junction temperature (TJ): 150 °C
- Package: TO220
- Manufacturer: Commonly produced by International Rectifier (now Infineon)
Typical applications
With its 250 V drain–source rating the IRF644A 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 ±30 V maximum; exceeding it punctures the gate oxide and destroys the device permanently.
Switching behaviour is characterised by a rise time of 17 ns and an output capacitance (Coss) of 180 pF, which together with the gate drive determines switching loss and the practical upper frequency limit.
Choosing a replacement for the IRF644A
A drop-in substitute for the IRF644A must be the same N-channel type and offer a drain–source rating of at least 250 V, a continuous drain current rating of at least 14 A and an on-resistance no higher than 0.28 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 IRF644A?
The IRF644A is an N-channel MOSFET (metal-oxide-semiconductor field-effect transistor). It is rated for 250 V drain-source and 14 A continuous drain current.
What is the maximum voltage of the IRF644A?
The IRF644A has a maximum drain-source voltage (Vds) of 250 V. Treat this as an absolute maximum and design with margin, especially when switching inductive loads.
How much current can the IRF644A handle?
It is rated for 14 A of continuous drain current, with power dissipation limited to 139 W. Real-world capability depends on your heatsinking and ambient temperature.
What is the on-resistance of the IRF644A?
On-resistance (Rds(on)) is 0.28 Ω. Multiply by the square of your load current to estimate conduction loss.
What package does the IRF644A 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 IRF644A?
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) | 250 V |
| Gate-Source Voltage (Vgs) | 30 V |
| Drain Current (Id) | 14 A |
| Drain-Source On-Resistance (Rds) | 0.28 |
| Rise Time (tr) | 17 nS |
| Output Capacitance (Coss) | 180 pF |
| Junction Temperature (Tj) | 150 °C |
| Package | TO220 |
| Power Dissipation (Pd) | 139 W |
Equivalent & Replacement Parts
No verified equivalents are listed for IRF644A yet.