The TPA3116D2DADR are digital amplifiers that are stereo-efficient. They can be used as a power stage to drive speakers with up to 100W / two in mono. Three devices share the same footprint which allows one PCB to function across multiple power settings.
SCR stands for Silicon-controlled rectifier. The SCR is a very important member of the thyristor family. It is more popular than another thyristor family members like TRIAC, and DIAC even though that thyristor is used interchangeably with SCR.