What this PNP transistor does in the circuit
The Infineon BC 807-16W E6327 is a PNP general-purpose switching transistor in the SC-70 / SOT-323 package. It serves as a low-power switch or amplifier in consumer, industrial, and automotive auxiliary circuits — relay drivers, LED switching, level shifters, and signal conditioning stages where the load current stays under 500 mA and the rail voltage does not exceed 45 V. The 200 MHz transition frequency means it handles moderate-speed switching up into the low-MHz range — fine for PWM dimming at tens of kHz, relay coil flyback control, or buffering logic-level signals. The 250 mW power limit keeps it in the small-signal category; dissipating more than a quarter watt calls for a larger device. The '16' in the base number indicates an hFE grouping of 100 to 250 at 100 mA collector current. The 100 minimum gain at 100 mA and 1 Vce means it saturates reliably driving loads up to its rated 500 mA, with the Vce saturation of 700 mV max at 50 mA base current.
Package and footprint — SC-70 / SOT-323
Housed in the 3-pin SC-70 / SOT-323 package, the BC 807-16W E6327 occupies about 2.1 x 2.0 mm of board area. The PG-SOT323 supplier package designation from Infineon matches the industry-standard SOT-323 footprint. The small SOT-323 body means hand rework is possible but tedious — hot-air rework with fine tweezers is typical. The 150°C junction temperature rating is the die limit, not the board temperature; the 250 mW power derates from 25°C ambient, so at 85°C ambient the usable power drops to about 180 mW.
Obsolete — what that means for procurement
Infineon lists the BC 807-16W E6327 as Obsolete. No last-time-buy window or successor part number is indicated in the available records. Sourcing this part now means going through independent distribution — surplus inventory, NOS (new old stock), or broker channels. Date codes will vary, and the supply is finite. Any buyer filling a BOM line with this MPN should qualify the parts for their application and verify authenticity, as the independent channel carries no factory warranty.
Leakage and off-state behaviour
Collector cutoff current is specified at 100 nA maximum (ICBO). In battery-powered circuits that spend most of their time in sleep, this leakage level is generally acceptable — it contributes about 0.3 mAh per year per transistor. At elevated junction temperatures the leakage rises, but the 150°C rating is the absolute limit, not a continuous operation target.