Dual NPN pre-biased — what the 47k/47k resistor pair buys you
The RN1904FE,LF(CT: That means each transistor is self-biased — you drop the two external resistors per channel from the BOM, and the pair occupies a single SOT-563 footprint. The 250 MHz transition frequency keeps edges clean for level shifting, relay drivers, or small-signal switching up into the low-MHz range.
Package and board-fit — ES6 vs SOT-563
The 100 mW max power limits the continuous current per channel in free air; at 25 °C ambient, each transistor's 100 mA rating is achievable only with moderate duty cycle or adequate copper area on the collector pads. CT is for prototype or low-volume builds.