Pre-biased NPN in a SOT-23 — what it saves on the board
The BCR533E6327HTSA1 is an Infineon NPN pre-biased transistor that integrates two 10 kOhm resistors — one in series with the base (R1) and one from base to emitter (R2) — so you skip the external bias resistor pair on the board.
330 mW power limit — derating in the SOT-23 footprint
Maximum power dissipation is 330 mW in the PG-SOT23 package — the limiting factor is the copper pad area under the transistor, not the silicon. At 500 mA the Vce(sat) is 300 mV typical at 2.5 mA base drive, so conduction loss stays under 150 mW in saturation. Transition frequency is 100 MHz, adequate for switching up to a few MHz in relay drivers, solenoid coils, and logic-level translators.
Last Buy — plan the LTB quantity now
Infineon lists the BCR533E6327HTSA1 as Last Buy — the final order window is open, and once it closes the part moves to end-of-life with no factory replenishment. For a BOM that needs this pre-biased NPN, the LTB quantity should cover the remaining production run plus a service-spare buffer.