Automotive-grade dual pre-biased NPN — what it replaces on the BOM
The Infineon BCR523UE6327 is a dual NPN pre-biased transistor qualified to AEC-Q101, meaning each of its two transistor cells integrates a 1kΩ base resistor (R1) and a 10kΩ emitter-base resistor (R2). This integration removes two external resistors per transistor — four resistors total — from the bill of materials, shrinking the footprint to a single SOT-23-6 Thin package (also listed as TSOT-23-6, supplier package PG-SC74-6-1).
Each NPN handles a continuous collector current (Ic) up to 500 mA with a collector-emitter breakdown voltage of 50 V — enough for 12 V and 24 V automotive loads with margin for load-dump transients. The 330 mW total power budget (both transistors combined) is the package-level thermal ceiling; derating applies above 25 °C ambient, as with any SOT-23-6 device. Vce saturation is specified at 300 mV maximum at a forced Ib of 2.5 mA and Ic of 50 mA, which is typical for a pre-biased part at moderate drive. The minimum DC current gain (hFE) of 70 at 5 mA, 5 V gives predictable on-state behaviour for low-side switched loads.
Switching speed and cutoff
Transition frequency (fT) is 100 MHz, so this part is comfortable switching PWM signals in the tens to low hundreds of kilohertz — suitable for dimming LEDs or driving small solenoids at audible frequencies and above. Collector cutoff current is a maximum 100 nA (ICBO), which matters for battery-powered modules where off-state leakage must stay negligible.