50 V pre-biased dual NPN — the BOM-saver for digital output stages
The Rohm IMH9AT110 packs two NPN transistors with integrated bias resistors into a single SC-74 (SOT-457) surface-mount package. Each transistor has a 10 kΩ series base resistor (R1) and a 47 kΩ base-emitter resistor (R2), so you drop two external resistors per channel from the BOM. The 50 V collector-emitter breakdown and 100 mA continuous collector current cover 24 V industrial logic, 12 V automotive relay pre-drivers, and 5 V level-shifting loads. Transition frequency of 250 MHz keeps switching clean for PWM up to several MHz.
300 mW total power — watch the derating in a tight layout
The 300 mW total power dissipation is shared between the two transistors. In a dense SMT6 layout with limited copper, derating applies above 25 °C. For continuous 5 mA per channel at 50 V Vce, the junction stays well within budget; pushing both channels to 100 mA simultaneously at high Vce will exceed the package ceiling. The SC-74 footprint is small, so thermal coupling between the two dies is close — treat the 300 mW as a hard package limit, not per-transistor.
The RoHS3 compliance covers current EU and global regulatory requirements.