BD679ASTU

The BD679ASTU is an NPN Darlington transistor manufactured by On Semiconductor (onsemi). It is designed for medium-power switching and amplification applications, offering a collector-emitter breakdown voltage of 80V, a continuous collector current of 4A, and a maximum power dissipation of 40W. The device features a high DC current gain (hFE) of 750 minimum at 2A collector current and 3V collector-emitter voltage, enabling efficient current amplification with low base drive requirements. The collector-emitter saturation voltage is 2.8V maximum at 2A collector current and 40mA base current.

This transistor is housed in a through-hole package compatible with TO-225AA and TO-126-3 outlines, with the supplier device package specified as TO-126-3. It can operate at a junction temperature up to 150°C. The NPN Darlington configuration integrates two transistors to achieve high current gain, making it suitable for driving loads such as relays, solenoids, and small motors. The through-hole mounting facilitates easy manual assembly and prototyping.

While the part is listed as RoHS3 compliant and REACH unaffected, these compliance claims are currently unverified. Designers should verify compliance status through official documentation before use in regulated applications.