Dual NPN pre-biased — what it saves on the board
The Toshiba RN1602(TE85L,F) packs two NPN transistors with integrated 10 kΩ base and emitter-base resistors into a single SC-74 (SOT-457) package. That means one component replaces two discrete transistors plus four resistors — cuts placement cost and board area on high-count I/O banks, relay drivers, or LED matrix columns where each channel needs a simple switch. Each transistor handles up to 100 mA collector current and 50 V Vce breakdown, with a transition frequency of 250 MHz — fast enough for 1–2 MHz switching in solenoid or small-motor drive. The 300 mW total power ceiling (both transistors) means derating is real in a dense layout; keep the ambient under 85 °C if both channels run near 50 mA continuous.
300 mW — the derating number that matters
The 300 mW max power is the sum of both transistors in the SM6 package. At 100 mA Ic and 300 mV Vce(sat) the per-channel dissipation is 30 mW, so you've got headroom — but if one transistor saturates at higher current or the board runs hot, the junction temperature climbs fast. The SOT-457 footprint has no thermal pad; the heat goes through the leads. On a 2-layer board with minimal copper, 200 mW continuous per package is a safer design target.
