NPN pre-biased transistor with integrated bias resistors
The Infineon BCR108E6433HTMA1 is an NPN pre-biased transistor in a SOT-23-3 package, integrating a 2.2 kΩ base resistor and a 47 kΩ emitter-base resistor. It switches loads up to 100 mA collector current at a 50 V collector-emitter breakdown voltage, with a 170 MHz transition frequency. The built-in bias network eliminates two external resistors per channel, saving board area and reducing pick-and-place cost in high-volume digital switching, relay drivers, and logic-level interface circuits.
New designs should evaluate a pin-compatible pre-biased NPN transistor in the same SOT-23-3 footprint to avoid a future last-time-buy event.
The 100 mA maximum collector current and 200 mW power dissipation limit this part to low-current switching — think driving a small relay coil, an LED string, or a logic-level buffer. The 300 mV saturation voltage at 500 µA base current and 10 mA collector current keeps conduction losses low in lightly loaded circuits. The 100 nA collector cutoff leakage suits battery-powered or high-impedance nodes where off-state current matters.
SOT-23-3 — rework-friendly footprint
The SOT-23-3 package is one of the easiest small-signal packages to rework by hand. With a hot-air station at 300°C and a fine tip, you can lift the part without lifting the pad, provided the board has adequate copper relief. The PG-SOT23 supplier device package is electrically identical to the standard SOT-23-3 footprint.