It is best suited for small and thin devices because the board area and component height can be reduced. The conventional type needs a large capacitor for output coupling capacitor when trying to pass low frequency range. On the otherhand, the output coupling capacitor-less type can achieve rich bass sound without attenuation in the low frequency range. In addition, there is no pop noise at start-up because there is no DC bias at start-up.
The recommended resistor values are shown in the application circuit examples in the datasheet. For BD88200GUL, BD88400GUL, and BD88400FJ, the recommended values are 10kΩ input resistor and 10kΩ feedback resistor. For BU7150NUV, the recommended values are 20kΩ input resistor and 20kΩ feedback resistor.
It is the abbreviation of Bridge Tied Load. It reverses the speaker both terminals to connect by using two amplifier circuits compared with a usual single amplifier. If without output coupling capacitor,it may has an advantage that output electric power quadruples.