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. LM386 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. Source - http://www.hqew.net/circuit-diagram/LM386-Audio-Amp-IC-Internal-Circuit-Schematic_5831.html