STMicroelectronics, 2-Channel, 28-Pin SOIC TDA7439DS13TR

The TDA7439DS is a volume, tone (bass, mid-range and treble) and balance (left/right) processor for quality audio applications in car-radio and Hi-Fi systems. Selectable input gain is provided. All the functions are controlled by serial bus.
The AC signal setting is obtained by resistor networks and switches combined with operational amplifiers.
The TDA7439DS employs BIPOLAR/CMOS technology to provide low distortion, low noise and DC stepping.

All functions are programmable via serial bus.
Input multiplexerfour stereo inputs selectable input gain for optimal adaptation to different sources
Treble, mid-range and bass control in 2-dB steps
Single stereo output
Two speaker attenuators:two independent speaker controls in 1-dB steps for balance facility independent mute function
Volume control in 1-dB steps