PNP pre-biased with integrated resistors — one part replaces three
The Infineon BCR555E6433 is a PNP pre-biased digital transistor in a SOT-23-3 package, with a 2.2 kΩ base resistor (R1) and a 10 kΩ emitter-base resistor (R2) built into the same die. This integration eliminates two external resistors per transistor, cutting placement cost and board area in dense automotive I/O, relay-driver, or solenoid-driver stages. Rated for 500 mA continuous collector current and 50 V collector-emitter breakdown, it handles the typical load currents of automotive auxiliary loads — small relays, LEDs, logic-level solenoids — without an external driver transistor.
Automotive-grade qualification and switching performance
The BCR555E6433 carries AEC-Q101 qualification, placing it in the automotive-grade bin for under-hood and cabin electronics where temperature cycling and reliability screening are mandatory. Transition frequency of 150 MHz ensures clean switching well into the hundreds of kilohertz, with a typical DC current gain of 70 at 50 mA, 5 V. Saturation voltage is 300 mV at 2.5 mA base, 50 mA collector — low enough to keep dissipation under the 330 mW power limit in the SOT-23 footprint.