CMOS inverter

Gradually increasing the size of a CMOS inverter in each cascaded stage ensures proper signal amplification and voltage levels throughout the circuit. Increasing the size of the inverters improves the overall voltage gain, enabling larger output voltage swings and enhancing noise immunity.

This gradual size increase helps maintain signal integrity, minimize signal degradation, and boost the overall performance of the cascaded CMOS inverter circuit.

Why We Use Cascaded Buffers Instead of Just Wider Transistors

When you need to drive a heavy load quickly, a single inverter isn’t enough—so we use a buffer designed for higher speed. A CMOS gate can drive more current if we increase the transistor’s channel width. Doubling the width lets us charge a capacitor twice as fast.

But here’s the issue: doubling the channel width also doubles the gate’s input capacitance. That means the previous stage will need more time to drive it, slowing everything down. So, we must balance input capacitance and driving strength.

To solve this, we cascade multiple inverters, each with increasing channel width. The first inverter handles the input with low capacitance, and the last provides strong drive to the load.