45 V / 500 mA general-purpose NPN — what it covers
The BC 817-16 E6433 is an NPN silicon transistor in a SOT-23-3 surface-mount package, rated for 45 V collector-emitter breakdown and 500 mA continuous collector current. With a DC current gain (hFE) of 100 minimum at 100 mA / 1 V, it handles low-side switching and linear amplification duties where you need moderate current and voltage headroom — relay drivers, solenoid kick, LED banks, or signal preamp stages. The 170 MHz transition frequency keeps it useful for audio-band and low-speed switching up to a few megahertz.
Obsolete — sourcing via the spot channel
This part carries an obsolete lifecycle status, meaning Infineon has ended regular production. Sourcing is through independent distribution — we locate available inventories from surplus, overstock, and end-of-life stockpiles. No successor order code is listed by the manufacturer; for a drop-in alternative in the same SOT-23 footprint, the BC817-25 (higher gain grade) is a common cross-shop candidate but has no official cross-reference to this code.
Package and thermal — SOT-23 fits tight boards
Housed in a TO-236-3 / SC-59 / SOT-23-3 case, the PG-SOT23 supplier package takes minimal board area — about 2.9 x 1.3 mm footprint. Maximum power dissipation is 330 mW, so thermal derating matters above 25 °C ambient; the junction temperature limit is 150 °C. For continuous loads near 500 mA, check the SOA curve and ensure adequate copper on the collector pad for heat spreading.
Vce(sat) and cutoff — switching efficiency
Saturation voltage is 700 mV maximum at 50 mA base / 500 mA collector — typical for a general-purpose NPN in this current class. Collector cutoff current is 100 nA maximum (ICBO), which is low enough for battery-powered circuits where off-state leakage matters. The 100 nA spec is at 25 °C junction; expect a decade increase per 25 °C rise above that.