3 A in a SOT-89-3 — thermal and layout notes
The STMicroelectronics 2STF1360 is an NPN bipolar transistor rated for 60 V collector-emitter breakdown and 3 A continuous collector current, housed in a SOT-89-3 surface-mount package. That current rating in this small footprint means the junction-to-ambient thermal path is the limiting factor — the 1.4 W maximum power dissipation assumes the SOT-89-3's collector tab is soldered to a decent copper area. The 130 MHz transition frequency and 500 mV Vce saturation at 150 mA base / 3 A collector make it a solid choice for medium-speed switching, linear regulators, and load switches in 12 V to 48 V industrial or automotive auxiliary rails. The 100 nA collector cutoff keeps leakage negligible at elevated temperatures.
Gain at load — base drive budget
Minimum DC current gain of 160 at 1 A collector and 2 V Vce means you need only about 6 mA base drive to saturate a 1 A load. At the full 3 A rating, the hFE drops — the datasheet's Vce saturation spec at 150 mA base / 3 A collector implies a forced beta of 20, so size the base resistor for worst-case saturation, not the high-current gain curve.