LM386 had been used for long time as an audio amplifier IC for low power applications. The schematic herein shows the LM386 internal circuit schematic.
can be seen in three flavors, there are LM386-1, LM386-2 and LM386-3.
Each of device provides 0.3W, 0.5W and 0.7W respectively.
See the LM386 datasheet here.