Pre-biased NPN in a small SC-70 package
The Infineon BCR135WE6327BTSA1 is an NPN pre-biased transistor in a surface-mount SC-70 (SOT-323) package. It integrates a 10 kΩ base resistor (R1) and a 47 kΩ emitter-base resistor (R2), so the switching threshold is set without external bias components — a BOM simplification for digital interface and load-switch roles where the base drive comes directly from a logic output or open-collector driver. Rated for a 50 V collector-emitter breakdown and 100 mA continuous collector current, with a transition frequency of 150 MHz, it suits low-to-mid speed switching in industrial control, relay drivers, and signal-level translation up to about 50 V rail.
Obsolete — what that means for sourcing
The BCR135WE6327BTSA1 carries an obsolete product status. Infineon no longer manufactures this exact variant, so the primary channel for procurement is independent distribution — parts are sourced from surplus inventory, overstock, or verified broker networks. For a production BOM that needs a drop-in replacement, the base product number BCR135 covers several package and resistor-configuration variants; the closest functional match within the same family shares the same 10 kΩ / 47 kΩ resistor divider and SC-70 footprint, but the exact suffix should be verified against the original design's electrical and thermal requirements.
250 mW power ceiling in a small footprint
Maximum power dissipation is 250 mW — a typical limit for the SC-70 package without a heatsink. In continuous operation, the collector current and VCE(sat) product must stay within this budget; at 100 mA and 300 mV saturation the dissipation is 30 mW, leaving ample margin, but a load that holds the transistor in the linear region at higher VCE will quickly reach the ceiling.