Package and mounting
The BCR116E6433HTMA1 is an Infineon NPN pre-biased transistor in a PG-SOT23 package, carrying a Last Buy lifecycle status. That means the manufacturer has scheduled end-of-production; remaining stock is finite and being drawn down. If you're repairing a board that uses this part, the scorch mark tells you which transistor failed — but the real question is whether you can get a genuine replacement before the channel dries up.
What the bias resistors do for your circuit
The integrated bias network — a 4.7 kΩ base resistor (R1) and a 47 kΩ emitter-base resistor (R2) — saves two external passives and shrinks the footprint to a single SOT-23. The R1/R2 ratio sets the turn-on threshold: with a 5 V logic drive, the base current is limited by R1, while R2 provides a bleed path to keep the transistor off when the drive is low. This is the same internal divider used across the BCR116 family, so if you're cross-referencing a replacement, those resistor values are the first thing to match.
Ratings that decide the fit
Collector-emitter breakdown is 50 V, and continuous collector current is rated 100 mA — comfortable for low-side switching of relays, LEDs, or small solenoids in 12 V or 24 V industrial logic. The 150 MHz transition frequency means it handles PWM into the low-MHz range without noticeable storage-time lag. Saturation voltage is 300 mV at 500 µA base drive and 10 mA collector current, which keeps dissipation low in saturated switching. Maximum power dissipation is 200 mW in the SOT-23 package — derate if ambient exceeds 25 °C or if the board has poor airflow.