Pre-biased NPN — the resistor divider is the part
The Toshiba RN1406,LF is an NPN pre-biased transistor in a S-Mini (SC-59 / SOT-23-3) surface-mount package. What makes it a 'digital transistor' is the monolithic bias network: a 4.7 kOhms base resistor (R1) and a 47 kOhms base-emitter resistor (R2) are integrated on the die. This eliminates two external passives from the BOM and shrinks the footprint to a single three-pin device.
50 V, 100 mA — where this sits in the switching lineup
Collector-emitter breakdown is rated at 50 V, continuous collector current at 100 mA, and saturation voltage is 300 mV at 250 µA base drive into 5 mA collector load. At 200 mW max power dissipation in the S-Mini package, derating is the main constraint above 85 °C ambient — the junction-to-ambient thermal path through the small SC-59 body limits continuous current in warm enclosures.