The 4.1W rating into 4Ω is the maximum continuous output power per channel at the specified load and supply voltage.
Depop, differential inputs, shutdown — why they matter
The depop circuit eliminates the audible pop when the amplifier turns on or off, which is critical for battery-powered devices where the amp cycles with the audio stream. Differential inputs reject ground-loop noise picked up on long input traces — useful when the audio source is a separate codec or Bluetooth module on the same board. The shutdown pin pulls the quiescent current to near zero, extending standby life in portable gear.
WLP package — plan the assembly process
The 16-WLP package is a bare-die-scale package with solder bumps directly on the die.