BU508AFI

The BU508AFI from STMicroelectronics is a high voltage fast-switching NPN power transistor designed for demanding applications such as horizontal deflection in color televisions. This transistor features a VCEO (IB=0) of 700 V and a VCES (VBE=0) of 1500 V, with a continuous collector current rating of 8 A and a peak current of 15 A. It offers a power dissipation of 50 W at a case temperature of 25°C, with a maximum junction temperature of 150°C. The storage temperature range extends from -65°C to 150°C, and the thermal resistance junction-to-case is 2.5°C/W.

The BU508AFI is housed in an ISOWATT-218-3 fully insulated package, providing an isolation voltage of 2500 V RMS from leads to heatsink, simplifying mounting and ensuring safety. The transistor is through-hole mounted with three leads. Key electrical characteristics include a collector-emitter saturation voltage of 1 V at 4.5 A and 2 A base current, a base-emitter saturation voltage of 1.3 V, a typical storage time of 7 µs, and a fall time of 550 ns under inductive load conditions. The transition frequency is 7 MHz. This part is manufactured using ST's Multiepitaxial Mesa technology with a Hollow Emitter structure for enhanced switching performance.