Pre-biased NPN — one less resistor on the BOM
That internal resistor sets the base drive, so the part switches on when the input voltage exceeds about 2.5 V (typical), and off below that threshold. For a procurement buyer, this means one fewer resistor to source, place, and inspect per switching node. The collector-emitter breakdown is rated at 50 V, and continuous collector current maxes at 70 mA — sized for logic-level loads, relay coils, and small-signal switching up to 150 MHz.
SC-75 package — tiny, but you can still hand-rework it
The BCR 149T E6327 comes in an SC-75 (SOT-416) package, supplier device code PG-SC75-3D. That's a three-lead package about 1.6 mm by 0.8 mm — small enough for dense boards but still large enough to rework with tweezers and a hot-air station if you keep the temperature under 300 °C and preheat the board. No exposed pad, so no thermal-via stitching needed — the 250 mW power limit is the total dissipation, and at 70 mA continuous you'll want to keep the ambient under 85 °C to stay inside that ceiling.