What this dual pre-biased transistor is for
The RN4906FE,LXHF(CT is an automotive-grade dual transistor from the AEC-Q101 series, integrating one NPN and one PNP pre-biased transistor in a single SOT-563 package. The built-in base resistor (R1) of 4.7 kΩ and emitter-base resistor (R2) of 47 kΩ eliminate two external resistors per channel, saving board space and reducing component count in switching and interface circuits. It is specified for surface-mount assembly and rated for a maximum power dissipation of 100 mW.
Key electrical ratings that decide the fit
The collector-emitter breakdown voltage is 50 V maximum, and the continuous collector current rating is 100 mA — suitable for driving low-power loads like relay coils, LED indicators, or logic-level interface transistors in 12 V automotive systems. The 300 mV Vce(sat) at 250 µA base current and 5 mA collector current keeps conduction losses low in saturated switching. DC current gain (hFE) is a minimum of 80 at 10 mA collector current and 5 V Vce, giving enough drive margin for typical microcontroller GPIO outputs. Off-state leakage is limited to 500 nA maximum.
Package and mounting for automotive PCBs
It is a surface-mount device intended for reflow soldering on standard FR-4 or automotive-grade PCB laminates. The compact 1.6 mm × 1.6 mm footprint suits space-constrained modules like engine control units, body controllers, or sensor interface boards where every square millimeter counts.