Pre-biased NPN in a tiny SC-70
The Infineon BCR129WH6327 is an NPN pre-biased transistor that integrates a 10 kΩ base resistor (R1) into the same SC-70 SOT-323 package. This eliminates one external resistor per switching node, which simplifies the BOM and shrinks the layout for high-density boards. It is rated for collector currents up to 100 mA and a collector-emitter breakdown voltage of 50 V, making it a fit for 24 V industrial logic and 48 V telecom control signals. The 150 MHz transition frequency keeps switching edges clean for low-speed PWM and relay drivers up to a few hundred kilohertz.
Saturation and drive margin
VCE(sat) is specified at 300 mV maximum with a base current of 500 µA and collector current of 10 mA. The minimum DC current gain of 120 at 5 mA, 5 V ensures consistent switching behaviour across production lots. Collector cutoff current is 100 nA maximum, which keeps leakage negligible in battery-powered or high-impedance circuits.
Package and power handling
Housed in a PG-SOT323-3-1 package (SC-70 equivalent), this is a three-lead surface-mount device. Maximum power dissipation is 250 mW, so it suits low-power switching and signal conditioning rather than continuous high-current loads. The small footprint makes it a candidate for space-constrained designs like sensor modules, I/O blocks, and portable equipment.