What this pre-biased NPN does on your board
The Infineon BCR148E6327HTSA1 is an NPN pre-biased transistor — a switching transistor with two 47 kΩ resistors integrated into the SOT-23 package. The base resistor (R1) and the base-emitter resistor (R2) are both 47 kΩ, eliminating the need for external bias components. This saves board space and reduces BOM count in low-current switching applications where the transistor is driven directly from a logic output or microcontroller GPIO.
Collector current is rated 100 mA maximum, and collector-emitter breakdown voltage is 50 V — suitable for driving relays, small solenoids, indicator LEDs, or level-shifting logic signals in 5 V and 12 V systems. The 100 MHz transition frequency is adequate for switching up to low-MHz PWM rates. Saturation voltage is 300 mV at 500 µA base drive and 10 mA collector current, which keeps conduction losses low in the on-state. The built-in 47 kΩ resistors set a fixed base current when driven from a known voltage. At 5 V logic, base current is roughly (5 V - 0.7 V) / 47 kΩ ≈ 91 µA, which with a minimum DC current gain of 70 at 5 mA gives ample drive for loads up to about 6 mA. For higher collector currents up to 100 mA, the base drive from the same resistor limits the available gain margin — the part is best suited for loads where the collector current stays under 30-50 mA in practice.
Last-buy status — what it means for procurement
The BCR148E6327HTSA1 carries a Last Buy lifecycle status. Infineon has scheduled this part for discontinuation, meaning the final production window is closing. Buyers should secure remaining inventory through independent distribution channels.