BFR84 MOSFET — Specifications & Equivalents

About the BFR84

The BFR84 is an N-channel MOSFET with a drain–source voltage (V_DS) rating of 25 V, a continuous drain current (I_D) of 0.05 A and an on-resistance (R_DS(on)) of 100 Ω. It can dissipate up to 0.3 W and is rated to a junction temperature of 150 °C. It is supplied in the TO72 package.

At a glance

• Type: N-channel MOSFET
• Max drain–source voltage (V_DS): 25 V
• Max continuous drain current (I_D): 0.05 A
• On-resistance (R_DS(on)): 100 Ω
• Power dissipation (P_D): 0.3 W
• Max junction temperature (T_J): 150 °C
• Package: TO72
• Manufacturer: Multi-source (Pro Electron registered part number)

Typical applications

With its 25 V drain–source rating the BFR84 sits in the very-low-voltage class of switching MOSFETs, typically found in battery protection and power-path switching, point-of-load converters and logic-level load switching in portable devices.

At 0.05 A it is aimed at small-signal and light-load switching rather than power conversion.

On-resistance of 100 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 ±6 V maximum; exceeding it punctures the gate oxide and destroys the device permanently.

Switching behaviour is characterised by an output capacitance (C_oss) of 5.5 pF, which together with the gate drive determines switching loss and the practical upper frequency limit.

Choosing a replacement for the BFR84

A drop-in substitute for the BFR84 must be the same N-channel type and offer a drain–source rating of at least 25 V, a continuous drain current rating of at least 0.05 A and an on-resistance no higher than 100 Ω if efficiency and heat matter.

Mechanically, check the replacement against the TO72 footprint and confirm the pin order — parts sharing a package outline do not always share a pinout.

Because BFR84 is a Pro Electron-registered part number rather than one vendor's proprietary series, it is produced by several manufacturers. Datasheet figures vary slightly between them, so check the datasheet of the brand you actually buy — this also makes like-for-like sourcing easier.

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 BFR84?

The BFR84 is an N-channel MOSFET (metal-oxide-semiconductor field-effect transistor). It is rated for 25 V drain-source and 0.05 A continuous drain current.

What is the maximum voltage of the BFR84?

The BFR84 has a maximum drain-source voltage (Vds) of 25 V. Treat this as an absolute maximum and design with margin, especially when switching inductive loads.

How much current can the BFR84 handle?

It is rated for 0.05 A of continuous drain current, with power dissipation limited to 0.3 W. Real-world capability depends on your heatsinking and ambient temperature.

What is the on-resistance of the BFR84?

On-resistance (Rds(on)) is 100 Ω. Multiply by the square of your load current to estimate conduction loss.

What package does the BFR84 come in?

It is listed in TO72. Verify the pinout of the specific variant, as one outline can carry different pin assignments.

What can I use to replace the BFR84?

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.