Class D mono amplifier in a 2.24×2.16 mm footprint
The TPA2100P1YZHT: The switching topology means the output stage runs in saturation, so efficiency stays high across the load range — useful when the amplifier shares a board with a battery or a 3.3V regulated rail and you want to minimise heat in a tiny package. The 16-DSBGA package measures 2.24×2.16 mm, which is about the size of a grain of rice. That footprint saves board space but demands a well-planned PCB layout: the BGA pads are under the part, so all routing exits through vias under the die or along the edges. The supply bypass caps need to sit as close as the layout allows — the datasheet's recommended decoupling layout is the starting point, not a suggestion.
The 2.5V to 5.5V supply covers single-cell Li-ion (3.0-4.2V nominal), two-cell alkaline, or a regulated 3.3V/5V rail. No external DC-DC converter is needed if the system already runs on one of those rails. Differential inputs let the amplifier reject common-mode noise picked up on long input traces — useful when the audio source is a codec or Bluetooth module on the other side of the board. The shutdown pin pulls the quiescent current to near zero, so the amplifier does not drain the battery when idle.
Because it is active and single-sourced from Texas Instruments, the supply chain is straightforward — no last-time-buy planning needed.