The LM4857 is an integrated audio sub-system designed for
stereo cell phone applications. Operating on a 3.3V supply, it
combines a stereo speaker amplifier delivering 495mW per
channel into an 8Ω load, a stereo headphone amplifier delivering
33mW per channel into a 32Ω load, a mono earpiece
amplifier delivering 43mW into a 32Ω load, and a line output
for an external powered handsfree speaker. It integrates the
audio amplifiers, volume control, mixer, power management
control, and National 3D enhancement all into a single package.
In addition, the LM4857 routes and mixes the stereo
and mono inputs into 16 distinct output modes. The LM4857
is controlled through an I2C compatible interface. Other features
include an ultra-low current shutdown mode and thermal
shutdown protection.