Based on your load requirement (5A), a switching buck converter rated for at least 5A and an input voltage of 20V is needed. One commonly used option is the LM2678-12 from Texas Instruments. This regulator is designed to output a fixed 12V at up to 5A, with an input voltage range that more than covers your 20V supply.
Key considerations:
Input/Output Requirements:
Input: 20V
Output: 12V, 5A rated
Design Guidelines:
Follow the datasheet recommendations regarding component selection (such as the appropriate inductor, input/output capacitors, and catch diode) to ensure stable operation and proper transient response.
Pay attention to PCB layout rules for high-current switching regulators, including proper trace widths and thermal management.
If you'd like further guidance on how to integrate this component into your schematic or need help with selecting the supporting passive components, let me know!