FC4B21320L MOSFET — Specifications & Equivalents
About the FC4B21320L
The FC4B21320L is an N-channel MOSFET with a drain–source voltage (VDS) rating of 12 V, a continuous drain current (ID) of 2.5 A and an on-resistance (RDS(on)) of 0.048 Ω. It can dissipate up to 0.34 W and is rated to a junction temperature of 150 °C. It is supplied in the XLGA004 package.
At a glance
- Type: N-channel MOSFET
- Max drain–source voltage (VDS): 12 V
- Max continuous drain current (ID): 2.5 A
- On-resistance (RDS(on)): 0.048 Ω
- Power dissipation (PD): 0.34 W
- Max junction temperature (TJ): 150 °C
- Package: XLGA004
Typical applications
With its 12 V drain–source rating the FC4B21320L 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.
The low 0.048 Ω on-resistance keeps conduction loss down, which suits synchronous rectification and continuous high-current paths.
Gate drive and switching notes
Keep gate–source voltage within the ±8 V maximum; exceeding it punctures the gate oxide and destroys the device permanently.
Switching behaviour is characterised by a rise time of 150 ns and an output capacitance (Coss) of 50 pF, which together with the gate drive determines switching loss and the practical upper frequency limit.
Choosing a replacement for the FC4B21320L
A drop-in substitute for the FC4B21320L must be the same N-channel type and offer a drain–source rating of at least 12 V, a continuous drain current rating of at least 2.5 A and an on-resistance no higher than 0.048 Ω if efficiency and heat matter.
Mechanically, check the replacement against the XLGA004 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 FC4B21320L?
The FC4B21320L is an N-channel MOSFET (metal-oxide-semiconductor field-effect transistor). It is rated for 12 V drain-source and 2.5 A continuous drain current.
What is the maximum voltage of the FC4B21320L?
The FC4B21320L has a maximum drain-source voltage (Vds) of 12 V. Treat this as an absolute maximum and design with margin, especially when switching inductive loads.
How much current can the FC4B21320L handle?
It is rated for 2.5 A of continuous drain current, with power dissipation limited to 0.34 W. Real-world capability depends on your heatsinking and ambient temperature.
What is the on-resistance of the FC4B21320L?
On-resistance (Rds(on)) is 0.048 Ω. Multiply by the square of your load current to estimate conduction loss.
What package does the FC4B21320L come in?
It is listed in XLGA004. Verify the pinout of the specific variant, as one outline can carry different pin assignments.
What can I use to replace the FC4B21320L?
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) | 12 V |
| Gate-Source Voltage (Vgs) | 8 V |
| Drain Current (Id) | 2.5 A |
| Drain-Source On-Resistance (Rds) | 0.048 |
| Rise Time (tr) | 150 nS |
| Output Capacitance (Coss) | 50 pF |
| Junction Temperature (Tj) | 150 °C |
| Package | XLGA004 |
| Power Dissipation (Pd) | 0.34 W |
Equivalent & Replacement Parts
No verified equivalents are listed for FC4B21320L yet.