The LM4937 is an integrated audio sub-system designed for mono voice, stereo music cell phones connecting to base band processors with mono differential analog voice paths. Operating on a 3.3V supply, it combines a mono speaker amplifier delivering 520mW into an 8 load, a stereo headphone amplifier delivering 36mW per channel into a 32 load, and a mono earpiece amplifier delivering 55mW into a 32 load. It integrates the audio amplifiers, volume control, mixer, and power management control all into a single package. In addition, the LM4937 routes and mixes the single-ended stereo and differential mono inputs into multiple distinct output modes. The LM4937 features an I2S serial interface for full range audio and an I2C or SPI compatible interface for control. The full range music path features an SNR of 85dB with an 18-bit 48kHz input.