Pre-biased NPN in a small SOT-323 — what the scorch mark tells you
The BCR148WH6327 is an Infineon NPN pre-biased transistor in a three-lead SC-70 (SOT-323) package. The integrated bias network — 47 kΩ base resistor and 47 kΩ base-emitter resistor — eliminates two external passives per switching node, which matters when you are squeezing a board into a tight corner or reworking a cramped assembly. Rated for 50 V collector-emitter breakdown and 100 mA continuous collector current, with a 250 mW power ceiling. Transition frequency sits at 100 MHz, so it handles low-speed switching and level-shifting cleanly.
Package and mounting
Vce saturation is 300 mV at 500 µA base drive and 10 mA collector load — that is the drop you will see across the transistor when it is fully on. DC current gain minimum is 70 at 5 mA collector current and 5 V Vce. Collector cutoff leakage is 100 nA maximum, which is tight enough that a pulled-up input will not false-trigger in a high-impedance node.
BCR148WH6327 carries an active product status. For a repair bench or a production BOM line that needs a known-good pre-biased NPN, this part is still in the channel without obsolescence pressure.