Obsolete — plan your BOM around independent supply
The BCR129SE6327HTSA1: For builds that already carry this dual NPN pre-biased transistor on the BOM, the only viable procurement path is the independent distribution market — surplus inventory, overstock, or last-time-buy leftovers.
Two NPNs with integrated base resistors in a SOT-363
The BCR129SE6327HTSA1 packs two NPN transistors, each with a 10kΩ base resistor built in, into a single PG-SOT363-PO package. That pre-biased arrangement cuts external component count — no separate resistor needed per transistor — which matters when you are squeezing a switching function into a tight layout. Each transistor handles up to 50V collector-emitter breakdown and 100mA continuous collector current, with a transition frequency of 150MHz. The 250mW power ceiling covers both transistors combined, so keep the total dissipation in mind when driving both channels simultaneously.
Where it fits — low-current digital switching
This dual transistor is a fit for board-level switching where you need to invert or buffer logic signals, drive a small relay coil, or level-shift a few milliamps. The integrated base resistor means the base drive is set by the 10kΩ value — the transistor turns on when the input exceeds roughly 0.7V plus the drop across that resistor. Surface-mount assembly in the SOT-363 footprint keeps the placement cost low.