F501 MOSFET — Specifications & Equivalents

About the F501

The F501 is an N-channel MOSFET with a drain–source voltage (V_DS) rating of 500 V, a continuous drain current (I_D) of 0.03 A and an on-resistance (R_DS(on)) of 750 Ω. It can dissipate up to 0.5 W and is rated to a junction temperature of 150 °C. It is supplied in the SOT23 package.

At a glance

• Type: N-channel MOSFET
• Max drain–source voltage (V_DS): 500 V
• Max continuous drain current (I_D): 0.03 A
• On-resistance (R_DS(on)): 750 Ω
• Power dissipation (P_D): 0.5 W
• Max junction temperature (T_J): 150 °C
• Package: SOT23

Typical applications

With its 500 V drain–source rating the F501 sits in the high-voltage (offline) class of switching MOSFETs, typically found in primary-side switching in offline SMPS (flyback, forward and quasi-resonant), active PFC boost stages, half-bridge and full-bridge inverters, induction heating and electronic ballasts and BLDC and AC motor drives. The rating leaves usable margin above the ~325 V DC bus obtained by rectifying 230 VAC mains, which is why this class dominates offline power supplies.

At 0.03 A it is aimed at small-signal and light-load switching rather than power conversion.

On-resistance of 750 Ω is relatively high, so this part is better suited to low duty-cycle or low-current switching than to continuous high-current conduction.

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 55.8 ns and an output capacitance (C_oss) of 4.53 pF, which together with the gate drive determines switching loss and the practical upper frequency limit.

Choosing a replacement for the F501

A drop-in substitute for the F501 must be the same N-channel type and offer a drain–source rating of at least 500 V, a continuous drain current rating of at least 0.03 A and an on-resistance no higher than 750 Ω if efficiency and heat matter.

Mechanically, check the replacement against the SOT23 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 F501?

The F501 is an N-channel MOSFET (metal-oxide-semiconductor field-effect transistor). It is rated for 500 V drain-source and 0.03 A continuous drain current.

What is the maximum voltage of the F501?

The F501 has a maximum drain-source voltage (Vds) of 500 V. Treat this as an absolute maximum and design with margin, especially when switching inductive loads.

How much current can the F501 handle?

It is rated for 0.03 A of continuous drain current, with power dissipation limited to 0.5 W. Real-world capability depends on your heatsinking and ambient temperature.

What is the on-resistance of the F501?

On-resistance (Rds(on)) is 750 Ω. Multiply by the square of your load current to estimate conduction loss.

What package does the F501 come in?

It is listed in SOT23. Verify the pinout of the specific variant, as one outline can carry different pin assignments.

What can I use to replace the F501?

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.