Two PNP pre-biased transistors in one SOT-563
The ROHM EMB51T2R packs two PNP pre-biased transistors into a single SOT-563 package, each with integrated 22kΩ base and emitter-base resistors. This is a space-saving building block for base-current-limited switching in low-power signal paths — think level shifters, logic inverters, or load switches where you want to drop the external bias resistor pair. The 50V collector-emitter breakdown gives headroom for 24V or 48V industrial rails, though the 150mW total power limit and 30mA max collector current keep it in the signal-level domain, not power switching.
22kΩ bias network — what it sets
Both R1 and R2 are 22kΩ, so the base is biased through a voltage divider that turns the transistor on when the input exceeds roughly half the supply. The 250MHz transition frequency means it handles a few MHz of switching without issue. Saturation voltage is 150mV at 500µA base and 5mA collector — useful for driving a logic input or a small LED without wasting rail headroom.
Active, ROHS3, and ready to quote
No last-time-buy or obsolescence concern here — it is a current-production part.