NPN pre-biased transistor with integrated bias resistors
The Infineon BCR108WH6433 is an NPN pre-biased transistor in a surface-mount SC-70 (SOT-323) package, designed for switching and driver applications where a single transistor with built-in bias resistors simplifies the BOM. The device integrates a 2.2 kOhms base resistor (R1) and a 47 kOhms emitter-base resistor (R2), eliminating two external passives per channel and saving board area in dense designs like relay drivers, LED indicators, or logic-level interface stages.
50 V breakdown, 100 mA collector current, 250 mW dissipation
With a collector-emitter breakdown voltage of 50 V and a maximum continuous collector current of 100 mA, the BCR108WH6433 handles common 12 V and 24 V industrial logic loads, small relays, and optocoupler drive circuits. The 250 mW power dissipation limit in the SC-70 package means the junction temperature stays within bounds for ambient operation up to roughly 85°C with derating — check the thermal impedance in the datasheet for your specific load duty cycle. The 170 MHz transition frequency is high enough for PWM switching up to several megahertz, though the real switching speed will be limited by the base resistor and the external drive impedance.
Low saturation voltage for efficient switching
The BCR108WH6433 saturates to a typical 300 mV at 500 µA base drive and 10 mA collector current, which keeps voltage drop low in saturated-switch applications. This matters when driving a 5 V relay coil or a 3.3 V logic input — the headroom loss is under 0.3 V, leaving the load with nearly the full supply rail.
Lifecycle status and compliance
The part is in the SC-70 (SOT-323) case, with the Infineon designation PG-SOT323-3-1. RoHS compliance is standard for this Infineon series, though the specific compliance statement should be verified in the manufacturer's documentation for your region.