UF302 200V 3A ULTRA FAST DIODE DO-201

If your board needs a fast rectifier that can carry up to 3 A at up to 200 V, and the old part is an axial ultrafast diode in a DO-201 body, this is the part to order. It switches off fast after conducting, so it wastes less power as heat in switching circuits than a slow rectifier would. It fits low to medium power systems where speed matters. It does not fit jobs that need more than 200 V, more than 3 A of average current, or a surface-mount body. Check the checks below before you order, so the voltage, the current, the speed, and the body all match your board.

This is an original, high-quality part.

What it does

A rectifier diode lets current flow one way and blocks it the other way, so it can turn alternating current into direct current and guard a circuit from reverse flow. An ultrafast diode does that job and then switches off very fast when the current flips. This UF302 diode needs only 50 ns at most to recover, so it keeps up with fast switching work in power supplies and similar circuits. A slow rectifier in the same spot would run hot and waste power, because it would keep passing current for too long after the flip.

This is an axial part with two wire leads. One end has a band on the body. That band marks the cathode end. It solders through holes on the board, and it mounts in any position.

Key features

• 200 V reverse voltage limit
• 3 A average forward current
• Ultrafast recovery: 50 ns at most
• Low forward voltage: 1.0 V at most at 3 A
• High surge strength: 150 A short surge limit
• Low reverse leakage: 10 µA at most at 25 °C
• Axial DO-201 body with wire leads for through-hole boards
• Band on the body marks the cathode end

Checks before you order

• Voltage: the peak reverse voltage on your circuit must stay at or below 200 V. The RMS voltage must stay at or below 140 V. If your circuit runs higher, this part is the wrong pick.
• Current: the average current must stay at or below 3 A, rated at 55 °C ambient. If your load is capacitive, cut the current by 20% from that limit, as the part’s own data says. If your circuit needs more, pick a higher current part, not this one.
• Speed: your circuit must need fast recovery. If the old part was a slow rectifier and the circuit never switches fast, a fast part still works, but check the forward voltage and surge limits all the same. If the old part was ultrafast, do not swap in a slow part — it will run hot.
• Package: your board must have through holes for a DO-201 axial body. This part has wire leads, not surface pads. Measure the old part or match it against the holes on your board.
• Polarity: match the band to the band mark on your board print. The band end is the cathode. A diode put in backwards will block the current it should pass.
• Heat: work out the heat from your real current and the 1.0 V drop at 3 A. Keep the leads at the rated length where you can, since the current rating counts on it.

Specifications

All figures below are for the UF302 diode at +25 °C unless noted. No figure here was guessed.

Other names for the same part (good to know)

Shoppers and repair techs call this same part by a few names. UF302 is the part number. UF302 diode is the part number with the word diode. 200V 3A diode is the plain name from its two headline limits. Ultrafast diode DO-201 and ultra fast rectifier diode are the plain names buyers use for its speed and its body. 200V ultrafast diode is the name buyers use when they need the 200 V value with fast recovery. If you see UF302 on an axial DO-201 body, and your circuit needs 200 V at 3 A with fast recovery, this page is the right match.

Frequently Asked Questions

What does ultrafast mean for this diode?

It means the diode stops passing current very fast after the current flips — 50 ns at most for this part. That fast stop keeps switching circuits cool and efficient.

Can I use this diode in place of a slow rectifier?

In most cases yes, if the voltage, current, surge, and body all match, because a fast diode can do a slow diode’s job. But check the forward voltage and the surge limit first. The reverse case is not safe: a slow diode in a fast switching circuit will run hot.

What voltage and current can this part handle?

It handles up to 200 V peak reverse voltage, 140 V RMS, and 3 A of average forward current at 55 °C ambient, with short surges up to 150 A. For a capacitive load, cut the current by 20% from the 3 A limit.

Which way round does this diode go?

The band on the body marks the cathode end. Fit the new diode with its band in the same place as the old diode’s band. If it goes in backwards, it will block the current it should pass.

What should I check before I order?

Check five things: voltage (200 V at most), current (3 A at most, less for capacitive load), speed (fast recovery needed), package (DO-201 axial body with leads), and polarity (match the band).

What is the price of this part?

Check the live price on the website. The price shown on the product page is the current one.

You can view and download the datasheet for this part from the Datasheet button on this page.

Use note kept from the old page: this part was listed before for power supplies, adapters, inverters, chargers and general repair work, in low to medium power systems, with an axial DO-201 body for easy mounting, and that use still stands.