The STMicroelectronics STF724 is a 30 V, 3 A NPN bipolar junction transistor in a surface-mount SOT-89-3 package (TO-243AA). It is a general-purpose power switching transistor rated for a maximum power dissipation of 1.4 W. Typical applications include low-to-moderate current switching loads such as relay and solenoid drivers, DC-DC converter output stages, and linear regulators where the 100 MHz transition frequency provides adequate switching speed for circuits operating up to a few megahertz.
The 30 V collector-emitter breakdown voltage and 3 A continuous collector current define the operating envelope. The saturation voltage of 1.1 V at 150 mA base drive and 3 A collector current means conduction losses of about 3.3 W at full rated current — well above the 1.4 W package limit, so continuous operation at 3 A requires derating or pulsed duty. The 100 MHz fT confirms this is a switching transistor, not an RF amplifier; it handles PWM frequencies in the tens to low hundreds of kilohertz comfortably.
There is no franchised factory pipeline for this part.
The STF724 is supplied in a SOT-89-3 package (JEDEC TO-243AA), a surface-mount power package with a large collector tab on the back side for heat sinking.