LM4902 audio power amplifier circuit

As shown in the figure, this is the LM4902 audio power amplifier circuit (MSOP package). After the audio signal is input, it is coupled to the inverting input terminal (pin 4) of the amplifier through Ci and Ri, while the non-inverting input terminal (pin 3) of the amplifier is connected to ground through CB. After power amplification, it is added to the speaker in the form of a bridge output from Vo1 (pin 5) and Vo2 (pin 8). There are two amplifiers inside the LM4902. The gain of the first amplifier is determined by the ratio of the external resistors RF and Ri, and the gain of the second amplifier is fixed to 1 by two internal 10kΩ resistors. When the Shutdown pin (pin 1) is at a logic low level, the amplifier is micro-powered off, and when it is at a logic high level, the amplifier works at full power.