What this pre-biased NPN does on the board
It handles up to 100 mA collector current with a 50 V breakdown, and the 150 MHz transition frequency covers most low-speed switching and level-shifting jobs in industrial or consumer gear. The SC-70 (SOT-323) package is small enough for tight layouts but still hand-solderable if you have steady tweezers and a fine tip — no hot-air station required for a field swap.
It is not yet obsolete, but the window to secure production quantities is closing. If this transistor is on your active BOM, now is the time to qualify a second source or stock up for the remaining production run.
Key ratings for the bench and the board
The built-in 4.7 kOhm base resistor sets the bias point — no external resistor needed for typical on/off switching at logic levels. Vce saturation is 300 mV maximum at 500 µA base current and 10 mA collector current, which keeps power dissipation low in saturated switching. The 250 mW power limit and 100 nA collector cutoff current define the thermal and off-state leakage boundaries for your design.