Adafruit Mono 2.5W Class D Audio Amplifier - PAM8302
Delivers up to 2.5 Watts into 4-8 ohm impedance speakers
Very efficient Class-D controller amp
Built in thermal and over-current protection
Fixed 24dB gain, onboard trim potentiometer for adjusting input volume.
Output is "Bridge Tied" meaning the output pins connect directly to the speaker pins, no connection to ground
This super small mono amplifier is surprisingly powerful it delivers 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. Since the amp is a class D, its very efficient (over 90% efficient when driving an 8Ω speaker at over half a Watt) - making it perfect for portable and battery-powered projects. There's even a volume trim pot so you can adjust the volume on the board down from the default 24dB gain. This board is a welcome upgrade to basic "LM386" amps!
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. All the above means that you can't connect the output into another amplifier, it should drive the speakers directly.
Item Specifics Output Power: 2.5W at 4Ω, 10% THD, 1.5W at 8Ω, 10% THD, with 5.5V Supply 50dB PSRR at 1KHz Filterless design, with ferrite bead + capacitors on output. Low current draw: 4mA quiescent and 0.5mA in shutdown (due to pullup resistor on SD pin) Size (without 0.1" header): 15mm x 24mm x 2mm / 0.6" x 0.9" x 0.08" Weight: 1.4g