Pre-biased PNP for automotive and industrial loads
The Infineon BCR198WH6327 is a PNP pre-biased transistor in the SC-70 / SOT-323 package, qualified to AEC-Q101 for automotive applications. It integrates two 47 kΩ resistors — one in series with the base, one between base and emitter — so the external bias network is already on-chip. Collector current is rated 100 mA continuous, with a collector-emitter breakdown of 50 V and a transition frequency of 190 MHz. Power dissipation is 250 mW in the surface-mount SOT-323 footprint.
The 47 kΩ base resistor (R1) and 47 kΩ emitter-base resistor (R2) set a fixed bias point — the transistor turns on when the base drive exceeds roughly 0.7 V plus the drop across R1. For a 5 V logic drive, the base current is limited to about 90 µA, which with a minimum hFE of 70 at 5 mA collector current ensures the device saturates with Vce(sat) of 300 mV at 500 µA base drive. That saturation voltage is tight enough for relay and solenoid drivers where the load is switched to ground through the PNP. The 190 MHz transition frequency means the transistor can handle PWM switching into the low-MHz range without significant gain roll-off. For a 20 kHz automotive PWM fan driver, the switching losses are negligible — the device spends most of its time in saturation or cutoff. The 100 nA collector cut-off current at 25°C gives adequate off-state leakage margin for battery-powered modules that must stay below a few microamps in sleep mode.
Sourcing and lifecycle posture
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