The BYW81P-200 is a standard fast-recovery rectifier diode rated for 200 V reverse voltage and 15 A average rectified current, with a reverse recovery time of 40 ns. It comes in a through-hole TO-220AC package, which is a common, easily hand-solderable footprint for power supplies, motor drives, and snubber circuits. The 40 ns trr makes it suitable for switching frequencies where a standard recovery diode would cause excessive losses or ringing, such as in 50-60 Hz rectification with a capacitive load or in flyback and forward converter output stages.
The BYW81P-200 is listed as obsolete, meaning the manufacturer no longer produces it. Availability is intermittent and pricing is quoted per lot at the time of request. A design review to qualify a modern fast-recovery diode with similar ratings (200 V, 15 A, 40 ns trr or better, in TO-220AC) is the recommended path for new production.
40 ns reverse recovery — the switching-speed edge
The 40 ns reverse recovery time is the headline switching parameter. It means the diode clears stored charge quickly when the voltage reverses, reducing turn-off losses and electromagnetic interference. For a 15 A part, this is a fast-recovery class, not an ultrafast or soft-recovery type. It works well in continuous-conduction-mode boost converters and as a freewheeling diode in low-to-medium frequency PWM motor drives where the switching frequency stays under a few tens of kilohertz. The 1.15 V forward voltage drop at 25 A is a typical figure for this speed class — expect slightly higher conduction loss than a slower 60 Hz rectifier, but the switching loss trade-off is worth it.
Package and mounting — through-hole simplicity
The TO-220AC package is a through-hole, single-ended power package with a metal tab for heatsinking. It is straightforward to hand-solder or wave-solder. The tab is electrically connected to the cathode (output), so the heatsink must be electrically isolated or the system must tolerate that connection. Reverse leakage is specified at 20 µA maximum at the rated 200 V, which is typical for a fast-recovery diode of this voltage class.