UF640 MOSFET — Specifications & Equivalents
About the UF640
The UF640 is an N-channel MOSFET with a drain–source voltage (VDS) rating of 200 V, a continuous drain current (ID) of 18 A and an on-resistance (RDS(on)) of 0.14 Ω. It can dissipate up to 139 W and is rated to a junction temperature of 150 °C. It is available in TO-263, TO-220, SOT-223, TO-252 and TO-220F packages, so confirm the pinout of the exact variant you order.
At a glance
- Type: N-channel MOSFET
- Max drain–source voltage (VDS): 200 V
- Max continuous drain current (ID): 18 A
- On-resistance (RDS(on)): 0.14 Ω
- Power dissipation (PD): 139 W
- Max junction temperature (TJ): 150 °C
- Package: TO-263, TO-220, SOT-223, TO-252, TO-220F
Typical applications
With its 200 V drain–source rating the UF640 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.
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 a rise time of 58 ns and an output capacitance (Coss) of 240 pF, which together with the gate drive determines switching loss and the practical upper frequency limit.
Choosing a replacement for the UF640
A drop-in substitute for the UF640 must be the same N-channel type and offer a drain–source rating of at least 200 V, a continuous drain current rating of at least 18 A and an on-resistance no higher than 0.14 Ω if efficiency and heat matter.
Mechanically, check the replacement against the TO-263, TO-220, SOT-223, TO-252 and TO-220F 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 UF640?
The UF640 is an N-channel MOSFET (metal-oxide-semiconductor field-effect transistor). It is rated for 200 V drain-source and 18 A continuous drain current.
What is the maximum voltage of the UF640?
The UF640 has a maximum drain-source voltage (Vds) of 200 V. Treat this as an absolute maximum and design with margin, especially when switching inductive loads.
How much current can the UF640 handle?
It is rated for 18 A of continuous drain current, with power dissipation limited to 139 W. Real-world capability depends on your heatsinking and ambient temperature.
What is the on-resistance of the UF640?
On-resistance (Rds(on)) is 0.14 Ω. Multiply by the square of your load current to estimate conduction loss.
What package does the UF640 come in?
It is listed in TO-263, TO-220, SOT-223, TO-252 and TO-220F. Verify the pinout of the specific variant, as one outline can carry different pin assignments.
What can I use to replace the UF640?
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) | 200 V |
| Gate-Source Voltage (Vgs) | 20 V |
| Drain Current (Id) | 18 A |
| Drain-Source On-Resistance (Rds) | 0.14 |
| Rise Time (tr) | 58 nS |
| Output Capacitance (Coss) | 240 pF |
| Junction Temperature (Tj) | 150 °C |
| Package | TO-263 TO-220 SOT-223 TO-252 TO-220F |
| Power Dissipation (Pd) | 139 W |
Equivalent & Replacement Parts
No verified equivalents are listed for UF640 yet.