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 8 load, a stereo headphone amplifier delivering 33mW per channel into a 32 load, a mono earpiece amplifier delivering 43mW into a 32 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.
| LM4857 | |
| Speaker Channels | Stereo |
| Speaker Output Power/Ch (W) | 1.2 |
| Speaker PSRR (dB) | 70 |
| Headphone Output Power/Ch (mW) | 75 |
| Headphone PSRR (dB) | 86 |
| Audio Mode Control | I2C |
| Supply Voltage (Min) (V) | 2.7 |
| Supply Voltage (Max) (V) | 5.5 |
