This post explains for the Audio Amplifier.
The Part Number is LTK8002D.
The function of this IC is Class-AB Audio Amplifier.
The package : SOP 8 Pin Type
Manufacturer: LTKCHIP TECHNOLOGY
This device is a 3W, mono AB audio power amplifier chip. The working voltage is 2V-5V, and the BTL bridge connection mode can provide 4Ω load with a THD less than 10% and an average output power of 3.0W under a 5V power supply voltage. In shutdown mode, the current typical value is less than 0.5uA. LTK8002D is specially designed to provide high-power, high-fidelity audio output. It only requires a small number of peripheral components and can work under low voltage conditions (2V-5V). LTK8002D does not require coupling capacitors, bootstrap capacitors or buffer networks, so it is very suitable for low-volume, low-power systems. […]
1. Built-in switch popping suppression circuit
2. 10% THD+N, VDD=5V, under 4Ω load, provide Up to 2.9W output power
3. 10% THD+N, VDD=5V, 8Ω load, provide Up to 1.8W output power
4. Shut-off current <0.5uA
5. Package mode: SOP-8
6. Overheat protection
2 page ( Block Diagram )
1. Plug-in speaker
2. Bluetooth speaker
3. Lithium battery amplifier
4. FM player