Principles of CMOS design

• Every input assignment should make the path from the output to exclusively $V_{cc}$ or ground (not both, otherwise you” get a short-circuit!)
• Take for instance this example. When A = 0, then the output is only connected to ground. When A = 1, the output is only connected to $V_{cc}$

Ensuring we don’t get a short circuit

• You can create the top half of the CMOS circuit, then copy and invert that top half onto the bottom half:
  • nMOS becomes pMOS and vice versa
  • series becomes parallel and vice versa
• That means creating one side basically GIVES you the other side!