Dual NPN with integrated bias resistors
The RN1708,LF is a dual NPN pre-biased transistor from Toshiba, packing two matched transistor cells with built-in bias resistors in a single SOT-353 package. The base resistor (R1) is 22 kΩ and the base-emitter resistor (R2) is 47 kΩ, which sets the turn-on threshold and eliminates the need for external bias components in low-current switching and driver stages.
Ratings that matter for the BOM
Collector current is rated 100 mA maximum, with a collector-emitter breakdown voltage of 50 V — this covers typical 5 V and 12 V logic-level loads with margin. Maximum power dissipation is 200 mW, so the part is suited for signal-level switching, not continuous high-current drive. Transition frequency is 250 MHz, which is plenty for low-speed multiplexing, I/O expansion, or relay driver applications up to a few megahertz.
Package and footprint for layout
Housed in a 5-pin SOT-353 (SC-70-5) with the supplier device package designation USV. Surface-mount mounting is standard.