BSN254 MOSFET — Specifications & Equivalents
About the BSN254
The BSN254 is an N-channel MOSFET with a drain–source voltage (VDS) rating of 250 V, a continuous drain current (ID) of 0.3 A and an on-resistance (RDS(on)) of 5 Ω. It can dissipate up to 1 W and is rated to a junction temperature of 150 °C. It is supplied in the TO92 package.
At a glance
- Type: N-channel MOSFET
- Max drain–source voltage (VDS): 250 V
- Max continuous drain current (ID): 0.3 A
- On-resistance (RDS(on)): 5 Ω
- Power dissipation (PD): 1 W
- Max junction temperature (TJ): 150 °C
- Package: TO92
Typical applications
With its 250 V drain–source rating the BSN254 sits in the medium-high-voltage class of switching MOSFETs, typically found in telecom and industrial DC rails, boost and flyback converters, LED and backlight drivers and power-factor-correction stages. Common where the bus sits well above 100 V but below rectified mains.
At 0.3 A it is aimed at small-signal and light-load switching rather than power conversion.
On-resistance of 5 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 an output capacitance (Coss) of 20 pF, which together with the gate drive determines switching loss and the practical upper frequency limit.
Choosing a replacement for the BSN254
A drop-in substitute for the BSN254 must be the same N-channel type and offer a drain–source rating of at least 250 V, a continuous drain current rating of at least 0.3 A and an on-resistance no higher than 5 Ω if efficiency and heat matter.
Mechanically, check the replacement against the TO92 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 BSN254?
The BSN254 is an N-channel MOSFET (metal-oxide-semiconductor field-effect transistor). It is rated for 250 V drain-source and 0.3 A continuous drain current.
What is the maximum voltage of the BSN254?
The BSN254 has a maximum drain-source voltage (Vds) of 250 V. Treat this as an absolute maximum and design with margin, especially when switching inductive loads.
How much current can the BSN254 handle?
It is rated for 0.3 A of continuous drain current, with power dissipation limited to 1 W. Real-world capability depends on your heatsinking and ambient temperature.
What is the on-resistance of the BSN254?
On-resistance (Rds(on)) is 5 Ω. Multiply by the square of your load current to estimate conduction loss.
What package does the BSN254 come in?
It is listed in TO92. Verify the pinout of the specific variant, as one outline can carry different pin assignments.
What can I use to replace the BSN254?
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.
Key Specifications
| Type | MOSFET |
|---|---|
| Channel Type | N -Channel |
| Drain-Source Voltage (Vds) | 250 V |
| Gate-Source Voltage (Vgs) | 20 V |
| Drain Current (Id) | 0.3 A |
| Drain-Source On-Resistance (Rds) | 5 |
| Output Capacitance (Coss) | 20 pF |
| Junction Temperature (Tj) | 150 °C |
| Package | TO92 |
| Power Dissipation (Pd) | 1 W |
Equivalent & Replacement Parts
No verified equivalents are listed for BSN254 yet.