FDB15N50 MOSFET — Specifications & Equivalents
Manufacturer: Commonly produced by Fairchild (now onsemi)
About the FDB15N50
The FDB15N50 is an N-channel MOSFET with a drain–source voltage (VDS) rating of 500 V, a continuous drain current (ID) of 15 A and an on-resistance (RDS(on)) of 0.38 Ω. It can dissipate up to 300 W and is rated to a junction temperature of 175 °C. It is available in TO263 and D2PAK packages, so confirm the pinout of the exact variant you order.
At a glance
- Type: N-channel MOSFET
- Max drain–source voltage (VDS): 500 V
- Max continuous drain current (ID): 15 A
- On-resistance (RDS(on)): 0.38 Ω
- Power dissipation (PD): 300 W
- Max junction temperature (TJ): 175 °C
- Package: TO263, D2PAK
- Manufacturer: Commonly produced by Fairchild (now onsemi)
Typical applications
With its 500 V drain–source rating the FDB15N50 sits in the high-voltage (offline) class of switching MOSFETs, typically found in primary-side switching in offline SMPS (flyback, forward and quasi-resonant), active PFC boost stages, half-bridge and full-bridge inverters, induction heating and electronic ballasts and BLDC and AC motor drives. The rating leaves usable margin above the ~325 V DC bus obtained by rectifying 230 VAC mains, which is why this class dominates offline power supplies.
Gate drive and switching notes
Keep gate–source voltage within the ±30 V maximum; exceeding it punctures the gate oxide and destroys the device permanently.
Choosing a replacement for the FDB15N50
A drop-in substitute for the FDB15N50 must be the same N-channel type and offer a drain–source rating of at least 500 V, a continuous drain current rating of at least 15 A and an on-resistance no higher than 0.38 Ω if efficiency and heat matter.
Mechanically, check the replacement against the TO263 and D2PAK 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 FDB15N50?
The FDB15N50 is an N-channel MOSFET (metal-oxide-semiconductor field-effect transistor). It is rated for 500 V drain-source and 15 A continuous drain current.
What is the maximum voltage of the FDB15N50?
The FDB15N50 has a maximum drain-source voltage (Vds) of 500 V. Treat this as an absolute maximum and design with margin, especially when switching inductive loads.
How much current can the FDB15N50 handle?
It is rated for 15 A of continuous drain current, with power dissipation limited to 300 W. Real-world capability depends on your heatsinking and ambient temperature.
What is the on-resistance of the FDB15N50?
On-resistance (Rds(on)) is 0.38 Ω. Multiply by the square of your load current to estimate conduction loss.
What package does the FDB15N50 come in?
It is listed in TO263 and D2PAK. Verify the pinout of the specific variant, as one outline can carry different pin assignments.
What can I use to replace the FDB15N50?
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) | 500 V |
| Gate-Source Voltage (Vgs) | 30 V |
| Drain Current (Id) | 15 A |
| Drain-Source On-Resistance (Rds) | 0.38 |
| Junction Temperature (Tj) | 175 °C |
| Package | TO263 D2PAK |
| Power Dissipation (Pd) | 300 W |
Equivalent & Replacement Parts
No verified equivalents are listed for FDB15N50 yet.