Philips Semiconductors Product specification, BU508AF is a high voltage, high-speed switching npn transistor in a fully isolated SOT199 envelope, primarily for use in horizontal deflection circuits of colour television receivers.
The BU508AF is a high‑voltage, high‑speed switching NPN power transistor offered in a fully isolated SOT199 package. It is primarily intended for horizontal deflection circuits in colour television receivers.
The document lists key parameters such as a 1500 V peak collector‑emitter voltage, 8 A continuous collector current (15 A peak), 34 W total power dissipation at 25 °C, and detailed thermal resistance values. Mechanical data, pin configuration, and safety notes for life‑support applications are also included.
| Collector‑emitter voltage (peak) | 1500 V |
|---|---|
| Collector‑emitter voltage (open base) | 700 V |
| Collector current (DC) | 8 A |
| Collector current (peak) | 15 A |
| Total power dissipation (25 °C) | 34 W |
| Storage temperature range | -65 °C to 150 °C |
| Maximum junction temperature | 150 °C |
| Thermal resistance (junction‑to‑heatsink, no compound) | 3.7 K/W |
| Thermal resistance (junction‑to‑heatsink, with compound) | 2.8 K/W |
| Thermal resistance (junction‑to‑ambient, free air) | 5 K/W |
The BU508AF can withstand a peak collector‑emitter voltage of 1500 V and an open‑base voltage of 700 V.
The device is rated for a continuous collector current of 8 A and a peak collector current of 15 A.
It can dissipate up to 34 W when mounted at a case temperature of 25 °C.
Junction‑to‑heatsink resistance is 3.7 K/W without compound and 2.8 K/W with compound; junction‑to‑ambient resistance is about 5 K/W in free air.