Digital DC 5V Amplifier Board Class D 2*3W USB Power Mini PAM8403 Audio Module 

Features:
Can use the computer USB port 5V power supply
or using a mobile phone charger USB port 5V power supply
battery power can also be used
high efficiency:90%
can provide 3W (left channel) +3 W (right channel) output power in the 4¦¸ load and 5V power supply conditions
A class, B class amplifier such efficiency is only about 30%
D class amplifier is highly respected today
D class amplifier efficiency is extremely high, not because of temperature affect the sound quality
but do not add heat sink and take less space
noise canceling circuit was built in the amplifier board
power on / off without pop noise
module has a short-circuit current protection and over-temperature protection

Application:
LCD TVs, monitors,
Laptop
Portable Speakers
Portable DVD players, game consoles
Phone / speakerphone
 
Specifications:
Operating voltage: 2.5V-5.5V
Speaker With:4-8ohms  recommended:4 ohms
Speaker Power :2-8W
Size:21 x 18 x 3.4mm(L x W x H)
Color:As the pics show
Net weight:1g

Package Contents:
1 x Amplifier Board

Note:
Left and right channel output of the "negative" and can not be together,
otherwise it will burn IC, and speaker(load) should be connected before power on.