20N03 MOSFET — Specifications & Equivalents

About the 20N03

The 20N03 is a MOSFET with a drain–source voltage (V_DS) rating of 30 V and a continuous drain current (I_D) of 20 A. It can dissipate up to 40 W and is rated to a junction temperature of 150 °C. It is supplied in the TO-252 package.

At a glance

• Type: MOSFET
• Max drain–source voltage (V_DS): 30 V
• Max continuous drain current (I_D): 20 A
• Power dissipation (P_D): 40 W
• Max junction temperature (T_J): 150 °C
• Package: TO-252

Typical applications

With its 30 V drain–source rating the 20N03 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

Keep gate–source voltage within the ±20 V maximum; exceeding it punctures the gate oxide and destroys the device permanently.

Choosing a replacement for the 20N03

A drop-in substitute for the 20N03 should match its polarity and offer a drain–source rating of at least 30 V and a continuous drain current rating of at least 20 A.

Mechanically, check the replacement against the TO-252 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 20N03?

The 20N03 is a MOSFET (metal-oxide-semiconductor field-effect transistor). It is rated for 30 V drain-source and 20 A continuous drain current.

What is the maximum voltage of the 20N03?

The 20N03 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 20N03 handle?

It is rated for 20 A of continuous drain current, with power dissipation limited to 40 W. Real-world capability depends on your heatsinking and ambient temperature.

What package does the 20N03 come in?

It is listed in TO-252. Verify the pinout of the specific variant, as one outline can carry different pin assignments.

What can I use to replace the 20N03?

This page lists 17 candidate equivalents matched on electrical ratings and package. Any replacement should meet or exceed the original voltage, current and dissipation figures and use a compatible drive level.