based on the IC PAM8302, this Class D audio amplifier board features differential input, bridge-tied output, and up to 2.5W amplification. compatible with a 4 to 8 ohm speaker. 'bridge-tied output' means the output pins connect directly to the speaker hook-ups without the need to tie into ground. if you are not using a source with differential input, please connect the 'A-' pin to Ground. the amplifier is Class D so this circuit is ideal for your portable projects or those needing a higher degree of efficiency.
powered by 2 - 5.5V supply for greater compatibility. with a 5.5volt supply, output is 2.5W with a 4ohm speaker, and 1.5W with an 8ohm speaker. board features a trim pot for volume adjustment.
datasheet for PAM8302 can be found here.