DC Switching Regulate 3A
Here is circuit switching regulator 5V 5A for digital circuit. Use IC LM2678-5.0 is High Efficiency 5V 5A Step-Down Voltage Regulator This is good power supply, small size and do not hot.
It is best a fixed regulator IC that high quality than 78xx series IC. It full 1A current output and not heat. Learn it more!