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VLSI Design · Module 3 of 10

CMOS and transistors

How real gates are built from transistors.

📖 Key ideas

  1. Modern chips use CMOS: pairs of NMOS and PMOS transistors.
  2. A CMOS inverter is one PMOS and one NMOS transistor.
  3. CMOS uses very little power when not switching.
  4. Power has dynamic (switching) and static (leakage) parts.
  5. Smaller process nodes (like 7 nm, 3 nm) pack more transistors but raise leakage and design difficulty.
💡 Real-life example: Like two taps on one pipe: when one opens the other closes, so water never runs straight through and wastes nothing.
CMOSComplementary metal-oxide-semiconductor
NMOSTransistor that conducts with a high gate
PMOSTransistor that conducts with a low gate
LeakageCurrent flowing even when idle