Texas Instruments provides a recommended PCB layout in the datasheet, but it's also important to follow general high-frequency PCB design guidelines, such as keeping the audio signal traces short and away from the power supply traces, and using a solid ground plane to reduce noise and EMI.
The gain setting of the LM4860M depends on the specific application and the desired output level. A good starting point is to set the gain to the recommended value in the datasheet, and then adjust it based on the measured output level and desired signal-to-noise ratio. It's also important to consider the input impedance and output impedance of the device when setting the gain.
The maximum power dissipation of the LM4860M is dependent on the ambient temperature and the thermal resistance of the package. According to the datasheet, the maximum power dissipation is 1.4W at an ambient temperature of 25°C. However, it's recommended to derate the power dissipation based on the actual operating temperature and thermal resistance of the system.
To reduce noise and EMI in an LM4860M-based design, it's recommended to use a low-noise power supply, decouple the power supply lines with capacitors, and use a shielded enclosure or a metal can package for the device. Additionally, it's important to follow good PCB design practices, such as keeping the audio signal traces away from the power supply traces and using a solid ground plane.
The recommended input and output coupling capacitor value for the LM4860M depends on the specific application and the desired frequency response. A good starting point is to use a 1uF to 10uF capacitor for the input and output coupling, and then adjust the value based on the measured frequency response and desired roll-off frequency.
LM4860M datasheet
by Texas Instruments
