This super small mono amplifier is able to deliver up to 2.5 Watts into 4-8 ohm impedance speakers. Inside the miniature chip is a class D controller, able to run from 2.0V-5.5VDC. It has built in thermal and over-current protection but we could barely tell it got hot. There's even a volume trim pot so you can adjust the volume on the board down from the default 24dB gain.
The A+ and A- inputs of the amplifier go through 1.0uF capacitors, so they are fully 'differential' - if you don't have differential outputs, simply tie the Audio- pin to ground. The output is "Bridge Tied" - that means the output pins connect directly to the speaker pins, no connection to ground. The output is a high frequency 250KHz square wave PWM that is then 'averaged out' by the speaker coil - the high frequencies are not heard.

Speaker is not included, use any 4 ohm or greater impedance speaker.

1.Output Power: 2.5W at 4ω, 10% THD, 1.5W at 8ω, 10% THD, with 5.5V Supply
2.50dB PSRR at 1KHz
3.Filterless design, with ferrite bead + capacitors on output.
4.Fixed 24dB gain, onboard trim potentiometer for adjusting input volume.
5.Thermal and short-circuit/over-current protection
6.Low current draw: 4mA quiescent and 1uA in shutdown mode.