MMBFJ305 MOSFET — Specifications & Equivalents

About the MMBFJ305

The MMBFJ305 is a MOSFET with a drain–source voltage (V_DS) rating of 30 V and a continuous drain current (I_D) of 0.008 A. It can dissipate up to 0.225 W and is rated to a junction temperature of 150 °C. It is supplied in the SOT-23 package.

At a glance

• Type: MOSFET
• Max drain–source voltage (V_DS): 30 V
• Max continuous drain current (I_D): 0.008 A
• Power dissipation (P_D): 0.225 W
• Max junction temperature (T_J): 150 °C
• Package: SOT-23

Typical applications

With its 30 V drain–source rating the MMBFJ305 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.

At 0.008 A it is aimed at small-signal and light-load switching rather than power conversion.

Choosing a replacement for the MMBFJ305

A drop-in substitute for the MMBFJ305 should match its polarity and offer a drain–source rating of at least 30 V and a continuous drain current rating of at least 0.008 A.

Mechanically, check the replacement against the SOT-23 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 MMBFJ305?

The MMBFJ305 is a MOSFET (metal-oxide-semiconductor field-effect transistor). It is rated for 30 V drain-source and 0.008 A continuous drain current.

What is the maximum voltage of the MMBFJ305?

The MMBFJ305 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 MMBFJ305 handle?

It is rated for 0.008 A of continuous drain current, with power dissipation limited to 0.225 W. Real-world capability depends on your heatsinking and ambient temperature.

What package does the MMBFJ305 come in?

It is listed in SOT-23. Verify the pinout of the specific variant, as one outline can carry different pin assignments.

What can I use to replace the MMBFJ305?

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.