Pre-biased PNP — what the integrated resistors mean
The Infineon BCR166E6327HTSA1 is a PNP pre-biased transistor — often called a digital transistor — that integrates the bias resistor network directly into the package. The base resistor (R1) is 4.7 kOhms and the emitter-base resistor (R2) is 47 kOhms, which sets a fixed input threshold and eliminates two external resistors from the BOM. This is a surface-mount device in the TO-236-3 / SC-59 / SOT-23-3 footprint, supplied as PG-SOT23.
50 V, 100 mA — where it fits
Collector-emitter breakdown is rated at 50 V, with a maximum collector current of 100 mA. Saturation voltage is 300 mV at 500 µA base current and 10 mA collector current, so conduction losses stay low in the on-state. DC current gain (hFE) is a minimum of 70 at 5 mA collector current and 5 V VCE.
160 MHz transition frequency — switching speed
With a transition frequency of 160 MHz, this transistor handles PWM switching well into the hundreds of kilohertz, making it suitable for switched loads in power management or signal conditioning paths. The 100 nA maximum collector cutoff current (ICBO) keeps leakage negligible at room temperature.
Last Buy — sourcing this part
The BCR166E6327HTSA1 carries a Last Buy lifecycle status. That means Infineon has scheduled this part for discontinuation, and the final window for placing orders through the factory channel is closing. The base product number is BCR166, so check for any remaining factory inventory or distributor stock before committing a long-run build.