This post explains for the Digital Audio Amplifier.
The Part Number is NS4358.
The function of this IC is 2.1-channel Surround Sound Digital Audio Amplifier.
The package is TQFN4×4-28, SOP-28.
Preview images :
NS4358 is an ultra low EMI, no filter, 5W + 3W × 2 high efficiency 2.1 channel + 3D surround stereo Class D audio Power amplifier. The NS4358 utilizes advanced technology to significantly reduce EMI interference over a full bandwidth range, minimizing damage to other components influences. Its output without the need for filter PWM modulation structure and feedback resistor built-in way to reduce the external components, the 2.1 channel function, 3D ring The surround sound function and bandpass filter are integrated on a single chip with minimal external components, the largest savings in PCB area and system cost.
NS4358 built-in overcurrent protection, overheating protection and undervoltage protection, effectively protect the chip in the abnormal working conditions are not damaged. and the use of spread spectrum technology to fully optimize the new circuit design, up to 90% more efficient for low voltage, high power output audio system.[…]