PNP pre-biased transistor with integrated resistors
The BCR 164F E6327: The Infineon BCR 164F is a PNP pre-biased digital transistor in a SOT-723 surface-mount package. It integrates a 4.7 kΩ base resistor (R1) and a 10 kΩ resistor between base and emitter (R2), eliminating two external passives from the BOM. Rated at 50 V collector-emitter breakdown and 100 mA continuous collector current, it handles low-side switching for relays, solenoids, LEDs, and logic-level interface loads. The 160 MHz transition frequency supports fast switching in DC-DC converters and level shifters up to a few MHz.
Bias resistor selection and switching envelope
The 4.7 kΩ base resistor sets the base current for a given drive voltage, while the 10 kΩ base-emitter resistor ensures a defined off-state. With a minimum DC current gain of 30 at 5 mA collector current and 5 V VCE, the part saturates at 300 mV maximum with 500 µA base drive and 10 mA collector load. The 100 nA collector cutoff current keeps leakage negligible in off-state.
SOT-723 footprint and power handling
Housed in a SOT-723 (PG-TSFP-3) package, the BCR 164F E6327 occupies roughly 1.4 mm² of board area — suitable for dense arrays or miniature modules. Maximum power dissipation is 250 mW, so the thermal budget limits continuous collector current at elevated ambient temperatures. Surface-mount assembly with standard reflow profiles works; the small body demands careful solder-paste volume control to avoid bridging.