AO3401 MOSFET — Specifications & Equivalents

About the AO3401

The AO3401 is a P-channel MOSFET with a drain–source voltage (V_DS) rating of 30 V, a continuous drain current (I_D) of 4.2 A and an on-resistance (R_DS(on)) of 0.064 Ω. It can dissipate up to 1.4 W and is rated to a junction temperature of 150 °C. It is supplied in the SOT23 package.

At a glance

• Type: P-channel MOSFET
• Max drain–source voltage (V_DS): 30 V
• Max continuous drain current (I_D): 4.2 A
• On-resistance (R_DS(on)): 0.064 Ω
• Gate threshold (V_GS(th)): 1.3 V
• Power dissipation (P_D): 1.4 W
• Max junction temperature (T_J): 150 °C
• Package: SOT23
• Manufacturer: Commonly produced by Alpha & Omega Semiconductor

Typical applications

With its 30 V drain–source rating the AO3401 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.

Gate drive and switching notes

A gate threshold (V_GS(th)) of 1.3 V means the AO3401 can usually be driven from 3.3 V or 5 V logic, though full enhancement still needs the gate taken clearly above the threshold.

Keep gate–source voltage within the ±12 V maximum; exceeding it punctures the gate oxide and destroys the device permanently.

Total gate charge (Q_g) of 9.4 nC sets the drive current required: average gate current is roughly Q_g × switching frequency, so faster switching needs a stronger driver.

Switching behaviour is characterised by a rise time of 3.2 ns and an output capacitance (C_oss) of 115 pF, which together with the gate drive determines switching loss and the practical upper frequency limit.

Choosing a replacement for the AO3401

A drop-in substitute for the AO3401 must be the same P-channel type and offer a drain–source rating of at least 30 V, a continuous drain current rating of at least 4.2 A, an on-resistance no higher than 0.064 Ω if efficiency and heat matter and a comparable gate threshold, so your existing gate drive still fully enhances the device.

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 AO3401?

The AO3401 is a P-channel MOSFET (metal-oxide-semiconductor field-effect transistor). It is rated for 30 V drain-source and 4.2 A continuous drain current.

What is the maximum voltage of the AO3401?

The AO3401 has a maximum drain-source voltage (Vds) of 30 V. Treat this as an absolute maximum and design with margin, especially when switching inductive loads.

How much current can the AO3401 handle?

It is rated for 4.2 A of continuous drain current, with power dissipation limited to 1.4 W. Real-world capability depends on your heatsinking and ambient temperature.

What is the on-resistance of the AO3401?

On-resistance (Rds(on)) is 0.064 Ω. Multiply by the square of your load current to estimate conduction loss.

Is the AO3401 logic-level compatible?

Its gate threshold is 1.3 V, so it can generally be switched from 3.3 V or 5 V logic. Drive the gate well above the threshold for full enhancement.

What package does the AO3401 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 AO3401?

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.