The audioprocessor TDA7437N is an upgrade of the TDA731X audioprocessor family. Due to a highly linear signal processing, using CMOS-switching techniques instead of standard bipolar multipliers, very low distortion and very low noise are obtained. Several new features like softmute, and zero-crossing mute are implemented.The soft Mute function can be activated in two ways: 1 Via serial bus (Mute byte, bit D0) 2 Directly on pin 28 through an I/O line of the microcontroller