The BC 817-40W E6327: The BC 817-40W is listed as obsolete by the manufacturer. That means Infineon has ended production — no last-time-buy window remains open through the franchised channel.
The 45 V collector-emitter breakdown voltage (Vceo) is the hard rail limit. The 500 mA maximum collector current sets the load-driving ceiling. The DC current gain (hFE) is the selection parameter that defines the 40-grade bin: a minimum of 250 at 100 mA collector current and 1 V Vce. That high beta means you get good saturation with modest base drive — useful in microcontroller-driven switches where the GPIO can only source a few milliamps. The 170 MHz transition frequency (ft) is adequate for switching up to a few megahertz; for higher-speed pulse applications you would step to a dedicated RF transistor. Maximum power dissipation is 250 mW. In a SOT-323 package that limits continuous collector current to roughly 100–150 mA before junction temperature becomes the constraint — the 500 mA Ic rating is a pulse or low-duty-cycle figure. The 150 °C maximum junction temperature (Tj) is typical for silicon, but the small package means thermal resistance is high; layout with adequate copper pour on the collector pad helps.
Package and footprint fit
The BC 817-40W E6327 comes in an SC-70 (SOT-323) surface-mount package, supplier device package PG-SOT323. That is a three-lead package with a 1.3 mm pitch — compact enough for dense boards but still hand-solderable with care. The collector is the center pin, which is the usual SOT-23 / SOT-323 pinout.