Pre-biased NPN in a tiny SOT-883 package
The BCR 149L3 E6327: NPN pre-biased transistor with a 47 kOhm base resistor (R1) integrated on die. Rated for 50 V collector-emitter breakdown and 70 mA collector current, transition frequency 150 MHz.
The 50 V Vce breakdown gives enough headroom for 3.3 V, 5 V, and 12 V rails without derating concerns. The 70 mA Ic limit covers small-signal switching — driving a relay coil, an LED string, or a logic-level load — but not a power stage. The 47 kOhm base resistor sets the base current for a given drive voltage; at 3.3 V logic drive, base current is roughly (3.3 V - 0.7 V) / 47 kOhm ≈ 55 µA, which with a minimum hFE of 120 at 5 mA yields adequate saturation for loads up to about 6 mA. For higher collector currents, the 300 mV Vce saturation at 10 mA (with 500 µA base drive) confirms the device saturates cleanly.
Package and footprint
SOT-883 (PG-TSLP-3-4) 3-pin leadless package. Surface-mount assembly with standard reflow profiles; 250 mW max power dissipation.